School Science Lessons
36.1 Astrology and the zodiac, models and demonstrations, space science
2012-05-05c SPw
Please send comments to: J.Elfick@uq.edu.au
Table of contents
36.44.0 Models and demonstrations
36.49 Angle of the Sun's rays on the Earth
36.40 Astrology and the zodiac
36.101.1 Atomic absorption spectroscopy
36.50 Calendars, the Star of Bethlehem and birth of Jesus
36.113 Inservice training - The Sun and the Earth, Equipment
36.48 Lengths of day and night
36.113.3 Measurements using the Earth
36.49.1 Moving models of the solar system, orrery
15.3.0.2 Rotational and translational kinetic energy of the Earth
36.47 Seasons
36.45 Solar eclipse simulation
37.34 Solar ultraviolet radiation
36.101 Spectroscope for materials analysis, shoe box spectroscope
36.51.0 Space science
36.113.5 Transit of Venus
History
36.51.0 Space science
36.52 Action-reaction engines
36.51 Action-reaction on roller skates
36.55 Angle, degree, arc minute, arc second, radian
3.32.1 Composition of the atmosphere and greenhouse gases
36.3.01 Composition of the Earth's crust, abundance of elements
36.3.02 Composition of the Sun, abundance of elements
36.108.03 Gravitational field of the Earth, g, gravitational constant, G
36.109 Gravitational potential energy
36.107 Kepler's laws of planetary motion
36.14.2 Light year, parsec
36.110 Mass, inertial mass and gravitational mass
37.44 Navigation data used by a ship at sea
36.108.01 Newton's universal law of gravitation, gravitational constant, G
27.4.2 Radiation pressure, "light pressure"
36.108.04 Satellite in stable orbit, geostationary orbit
27.1.70 Scattering, Rayleigh scattering, Mie scattering, blue sky and red sun
37.34 Solar ultraviolet radiation
36.53 Thrust experiments
36.108.02 Weight of an object and g
36.54 Weightlessness, reference systems
36.14.0 Stars and planets
36.16 Albedo
36.74 Aldebaran, Alpha Tauri
36.72 Alpha Centauri (Rigil Kentaurus)
6.3.3.2 Angle, degree, arc minute, arc second, radian
36.21 Apparent daily rotation of the sky, the axis of rotation of the Earth
36.75 Arcturus, arctic, the Great bear
3.3.2.0 Astronomical unit
36.17 Azimuth, altitude, zenith and horizon, the horizontal system of co-ordinates
36.76 Constellarium
36.76.1 Constellarium, Umbrella constellarium
36.112 Constellations, List of constellations
36.4.1 Declination calculation
36.14.1 Diurnal aberration of a star
36.22 Ecliptic
36.23 Ecliptic, Obliquity of the ecliptic, precession and nutation
3.8.0 Ellipse
36.8.1 Equation of time
36.20 Equatorial system of co-ordinates
36.26a Falling stars, shooting stars, meteors
36.14 Find the main constellations
36.18 Find constellations from north of the equator, Northern hemisphere
36.19 Find constellations from south of the equator, Southern hemisphere
36.12.2 Great circles
36.11 Greenwich Mean Time, GMT, UTC
36.112 List of constellations
36.14.2 Light year, parsec
36.12.03 Lunar month, synodic month
36.15 Magnitude
36.10 Make a range finder
36.11 Make a model Earth
36.12.04 Meridians, celestial meridian, standard meridian
36.26 Morning Star and Evening Star, Venus
36.13 North, Find due north
26.12.05 Period of rotation
36.92 Photograph constellations
36.93 Photograph satellites
36.39 Photograph star trails
36.91 Photograph star trails in colour
36.27 Planet movements in a jar
36.24 Pluto, Is Pluto a planet?
36.108.04 Satellite in stable orbit, geostationary orbit
36.106 Satellite launcher
36.77 Seasonal shift of the sky
36.12.3 Ship's watches
36.12.02 Sidereal time
36.25 Solar system model
36.78.1 Star calendar
36.78.2 Star clock
6.20 Southern Cross constellation (Primary)
36.7.0 Sunrise and sunset
36.76 Supernova
36.73 The universe
36.78 Time and date using the stars
36.12.1 Tropical year
36.94 "Twinkle, twinkle little star"
36.4.0 Sundials
36.70.5 Build a sundial
36.4.0 Demonstration sundials
36.6.0 Find north by the length of a shadow during the day
36.5.0 Flowerpot sundial
36.6.1 Length of a sundial shadow during the year
36.8.0 Make a sundial
36.70.6 Pocket sundial
4.42 Sundials (Primary)
36.69 Sundial for the home
36.68 Sundial for the Southern hemisphere
36.70.1 Universal globe sundial
36.3.01 Composition of the Earth's crust, abundance of elements
Elements can combine to form natural compounds called minerals. For example,  oxygen and silicon
combine to form silica SiO2 that occurs as the common mineral quartz. Many different versions exist of
tables to show the most abundant elements in the Earth's crust.
Element % Mass Element % Mass
Oxygen 46.71 Carbon 0.094
Silicon 27.69 Manganese 0.09
Aluminium 8.07
 Barium 0.05
Iron 35.05
 Sulfur 0.052
Calcium 3.65
 Chlorine 0.045
Sodium 2.75 Nitrogen 0.03
Potassium 2.58
 Chromium 0.035
Magnesium 2.08
 Fluorine 0.029
Titanium 0.62 Zirconium 0.025
Hydrogen gas
 0.14 Nickel 0.019
Phosphorus 0.13 all other elements 0.061
36.3.02 Composition of the Sun, abundance of elements
Element % Mass
Hydrogen, H
 54.0
Helium, He
 44.7
Oxygen, O2
 0.8
Carbon, C
 0.4
Silicon, Si
 0.05
36.4.0 Demonstration sundials
See diagram 36.68: Shadow stick sundial, Circular plate sundial
1. Make a shadow stick sundial. Demonstrate a simple sundial by placing an upright stick in the ground
so that it is not in the shade. At hourly intervals, mark the position of the shadow from the top of the stick
on the ground.
2. Make a simple dial from a circular metal or plastic plate divided into 24 equal arcs. Push a steel knitting
needle through the centre of the plate so that the plane of the plate is at right angles to the needle. Fix the
plate so that the gnomon, (i.e. the needle), points towards the celestial pole. If the noon position of the
shadow of the gnomon falls on the XII marking, the shadow will then fall on the other markings,  close to
correct time. Mark the plate on both sides because the shadow of the  gnomon will move from one side
to the other as the Sun's declination changes.
36.5.0 Flowerpot sundial
Use a stick fixed through the hole in a flowerpot. Mark the position of the shadow on
the flowerpot rim each hour.
36.6.0 Find north by the length of a shadow during the day
See diagram 36.6: Brisbane shadow height measurements 2009-07-27
Brisbane city, 2009-07-27, Latitude: -27o28', Longitude: 153o1, Height: 0.0 m
Time zone : + 10 hours.
Time Azimuth Difference Altitude
9.00 46o59' . 27o04'
10.00 33o51' 13o08' 35o43'
11.00 17o17' 16o34' 41o30'
12.00 358o13' 19o.04' 43o19'
13.00 339o25' 18o48' 40o43'
14.00 323o27' 15o58' 34o21'
15.00 310o53' 12o34' 25o17'
Use a large sheet of paper and a 50 cm stick fixed vertically on the paper. Select an open space
exposed to the Sun. Select an open space exposed to the sun. Mark the position of the base of the stick.
Every 15 minutes mark the position of the end of the stick's shadow and write the time of observation
next to the mark. Use a soft pencil to  draw a curve linking the positions of the ends of the shadows.
Mark where the shadow was at minimum length. Record the date. Draw the position of true north.
36.6.1 Lengths of a sundial shadow during the year, analemma
See diagram 36.6.1: Length of a sundial shadow during the year
See diagram 36.6.2: Analemma curve
The apparent path of the sun in the sky during the year is called the analemma. The path can be shown by
direct photographs of the sun each day or by recording the position of the shadow of a vertical rod or
gnomon at the same time each day, e.g. at noon. The analemma curve is the figure of eight formed by
plotting the position of the sun at the same place and at the same time during the year. The variation along
the long axis of the 8 is caused by the Earth's axial inclination. It is highest at the summer solstice and
lowest at the winter solstice. Variation across the short axis is caused by the eccentricity of the Earth's
orbit.
36.8.0 Make a sundial
See diagram 36.69: Sundial for the Northern hemisphere
Make the base with a flat rectangular piece of wood. The gnomon ABC is a thin triangular piece of metal.
Angle ABC = latitude and angle ACB = 90o. Use a spirit level to test that the base is horizontal. The
central line must lie along the north-south line, i.e. the meridian. Fix the gnomon vertically so that the
hypotenuse points towards the pole star, (north star, lodestar), in the Northern hemisphere and the
celestial south pole in the Southern hemisphere. For approximate results, make the hour markings by
noting the position of the shadow of the gnomon at hourly intervals, using a watch set to local mean time.
Get more accurate results by making the markings 15 April, 15 June, 1 September or 24 December,
when there is no difference between watch time and dial time. The markings are symmetrical about the
central line XY so do not calculate other angles. If the base of the dial is made vertical, then the angle
between the gnomon and the base must equal 90o minus the latitude.
36.40 Astrology and the zodiac
[Greek zōion, animal, (Most of the zodiac signs are animals.)]
1. The ecliptic is divided into 12 equal sections of 30o, each containing a constellation, a sign of the zodiac.
On or near 21 March each year the Sun moves into 0o of Aries, first point of Aries, which defines the
start of the tropical year of 365.242 194 mean solar days. The timetable for the Sun passing through the
12 signs of the zodiac as follows, may vary plus or minus 1 day depending on leap years:
Constellation Period
Aries (Ram) 21 March – 20 April
Taurus (Bull) 21 April – 20 May
Gemini (Twins) 21 May – 21 June
Cancer (Crab) 22 June – 23 July
Leo (Lion) 24 July – 23 August
Virgo (Virgin) 24 August – 23 September
Libra (Scales, balance) 24 September – 23 October
Scorpius (Scorpion) 24 October – 22 November
Sagittarius (Archer) 23 November – 22 December
Capricorn (Goat) 23 December – 20 January
Aquarius (Water carrier) 21 January – 19 February
Pisces (Fish) 20 February – 20 March
2. The zodiac is the circular band of stars seen along the same path as the Earth's orbit around the Sun.
It is a belt on the celestial sphere 8o on either side of the ecliptic, forming a background to the motion of
the Sun, Moon and planets. In twelve groups, these stars make up the twelve signs of the zodiac, each
30o long. They are named after the constellations identified during the time of the ancient Greek
astronomers. Astrologers believe that the positions of heavenly bodies when you were born influence what
you are so they match zodiac signs with human characteristics.
The ascendant is a point on the ecliptic, i.e. degree of the zodiac rising above the eastern horizon just as
a particular event occurs, especially the birth of a child. This point changes as the Earth rotates on its axis.
The "house of the ascendant" is defined as 5 degrees of the zodiac above down to 25 degrees of the
zodiac below the point. Any planet "within the house" is called "lord of the ascendant" and is supposed to
influence the life of the child. So a person gaining in influence or prosperity is said to be "in the ascendant".
3. Some traits associated with signs of the zodiac:
Aquarius: erratic, detached, honest (The "age of Aquarius" is supposed to be a time of freedom, including
sexual freedom, and general brotherhood.)
Aries: aggressive, courageous, self-motivating, impulsive, dynamic, selfish, irascible.
Aries was the first constellation of the zodiac but the vernal equinox, the point at which the Sun crosses
the celestial equator from south to north, also called the spring equinox and the first point of Aries, is now
moved into the area of Pisces because of  precession causing the movement westwards by one seventh
of a second of arc daily.
Cancer: persistent, possessive, moody, cautious
Capricorn: resent interference, patient, careful, fatalistic
Leo: leadership ability, generous, egotistical, patronizing
Libra: fair minded, diplomatic, urbane, indecisive, during 24 September to 23 October the day and night
periods are about equal, i.e. have equal "weight", so are "balanced"
Pisces: creative, changeable, emotional, intuitive
Sagittarius: friendly, optimistic, enthusiastic, restless
Scorpio: subtle, determined, possessive, compulsive
Taurus: determined, practical, unemotional, inflexible
Virgo: modest, diligent, reliable, fussy
4. List which of the traits in the list describe yourself and a friend. Then ask the friend
to make a similar list. Note how many traits in the list were according to the
astrological prediction.
36.44 Phases of the Moon and lunar eclipses
See diagram 36.95: The Moon in the sky
1. Fix an electric torch to shine full on a white ball as a Moon. Hold an Earth ball in position to view the
white ball Moon from different directions and see crescent quarter phases, gibbous, and full Moons.
Rotate the Earth globe to show how the times of rising and setting of the Moon are closely related to the
phase. For example, the first quarter Moon rises about noon, is highest in the sky at sunset, and sets
about midnight. By sighting across the position on the globe corresponding to your own geographic
locality, simulate the relationship of the Moon to the horizon for Moon rise and Moon set positions
2. Place the white ball Moon in the shadow cast by the Earth globe to simulate a partial or total lunar
eclipse. Place the Moon between the electric torch and the globe so that its shadow is cast on the Earth.
Show that an eclipse of the Sun is not visible over as great an area of the Earth as an eclipse of the Moon,
which is seen from the entire half of the Earth that is towards the Moon.
36.45 Solar eclipse simulation
See diagram 36.96: Simulated solar eclipses
Represent the Sun with an opal electric bulb shining through a circular hole 5 cm in diameter in a piece of
blackened cardboard. Draw the corona in red crayon around this hole. The Moon is a wooden ball, 2.5
cm diameter, mounted on a knitting needle. View the eclipse through any of several large pin holes in a
screen on the front of the apparatus. The corona becomes visible only at the position of total eclipse.
Adjust the Moon's position with a wire bicycle spoke attached to the front of the apparatus.
36.46 Eclipse does not occur at every new and full Moon
See diagram 36.97: Eclipse of the Sun and the Moon
A eclipse of the Sun B eclipse of the Moon C no eclipse The Moon's orbit is inclined enough to cause the
Moon usually to pass above or below the Earth's shadow or the region between the Earth and the Sun.
36.47 Seasons
See diagram 36.98: The cause of seasons
The Sun travels about eight days longer in the Northern Hemisphere than in the Southern Hemisphere.
Use a hollow rubber ball to represent the Earth. Push a 15 cm length of wire or a knitting needle through
the ball to represent the Earth's axis. Draw a circle about 40 cm in diameter on a piece of cardboard to
represent the Earth's orbit. Hang an electric lamp about 15 cm above the centre of the cardboard to
represent the Sun. Place the ball representing the Earth successively at the four positions shown in the
diagram with the axis slanted about 23.5o. Observe how much of the ball that is always illuminated.
Observe where the direct rays of the Sun strike. Observe which hemisphere receives the slanting rays of
the Sun. Repeat the experiment with the needle perpendicular to the table top in each of the four positions
and observe what would happen if the axis of the Earth were not inclined.
36.48 Lengths of day and night
See diagram 36.99: Differences in the length of day and night
Days and nights are of equal length only at the equator. Draw a large circle to represent the Earth's orbit.
Draw two lines perpendicular to each other through the centre. Where they cut the circle, label the
intersections in counter clockwise order: 20 March, 21 June, 23 September, 21 December. These are
positions of the Earth in relation to the Sun on these dates. Draw a small circle for the Earth at the 21 June
position. The north pole will be off centre about radius of the circle, towards the Sun. For any other date
or orbital position, which can be located by using a protractor, the Earth circle and pole will have the
same orientation. The Arctic circle, tropic of Cancer, and equator can be drawn in. Then a line through
the centre of the Earth circle and perpendicular to the Earth-Sun line will be the boundary between
daylight and darkness. From such a diagram, estimate the duration of sunlight at different latitudes for any
date, e.g. on 1 August at the Arctic circle the Sun would be estimated as up for about 18 hours, but up
only 6 hours on 1 November.
36.49 Angle of the Sun's rays on the Earth
If the rays from the sun are assumed to be parallel, then the heating effect of the Sun on the Earth can be
seen to be greatest at the equatorial region not because the equator is closest to the earth but because the
Earth curves less in the equatorial  region. Also, the rays of the Sun have less atmosphere to pass through
in the equatorial region.
Show the effect of the angle of the Sun's rays on the amount of heat and light received  by the Earth. Bend
a piece of cardboard and make a square tube 2 cm × 2 cm × 32  cm. Use a piece of very stiff cardboard
and cut from this a strip 23 cm long and 2 cm wide. Paste this to one side of the tube with 15 cm
xtending. Rest the end of the stiff  cardboard on the table and incline the tube at an angle of about 25o.
Hold a flashlight or lighted candle at the upper end of the tube and mark off the area on the table covered
by the light through the tube. Repeat the experiment with the tube at an angle of about 15o. Repeat again
with the tube vertical. Compare the size of the three spots and find the area of each. Show the analogy
between this investigation and the way in which the Sun's rays impinge on the Earth's surface. Note
whether the amount of heat and light received per unit area from the Sun is greater when the rays are
slanting or direct.
36.49.1 Moving models of the solar system, orrery
In 1700 the Earl of Orrery in Ireland ordered the construction of a model of the universe made of wood
and brass. By turning a handle the model planets could correctly turn about the sun in their respective
orbits. The orrery became a popular toy and is still used in school science laboratories to demonstrate the
relative movements of the planets.
Commercial "Rotating space gallery. An interactive 3D model of the solar system."
36.50 Calendars, the Star of Bethlehem and birth of Jesus
1. An almanac is a yearly prediction of the position of celestial bodies. The ancient  Egyptians used a
calendar based on the solar year. The ancient Babylonians, Hebrews  and Muslims used a calendar based
on a lunar year of 12 months, 11 days shorter than the solar year so an extra month was added every
third year. The Roman calendar had 10 months until in 46 B.C. Julius Caesar ordered a revised calendar,
Julian calendar, of 12 months with an extra day, leap day, added every fourth year of  365 days. The
number of days in the months became the same as now. In AD 321,  Emperor Constantine ordered the
seven day week with Sunday as the first day.
In AD 1582, Pope Gregory XIII, ordered the change from the Old Style or Julian  Calendar with a solar
year of 365.25 days, longer than the tropical year by about 11 minutes, to a New Style or Gregorian
Calendar with a solar year of 365.242 546  days. This produces an error of 3 days every 400 years, so
3 out of 4 centennial years  are not leap years. The leap day is not inserted in century years not divisible
by 400,  i.e. 1700, 1800 and 1900, but year 2000 was a leap year. In a leap year, feast days  after
February occur two days of the week later than the previous year, instead of the  usual one after the
previous year, so the festival days "leap" a day. The Gregorian calendar was not adopted in Great Britain
until January, 1752. The Jewish Calendar dates from the Creation fixed at 3761 B.C. The Mohammedan
Calendar dates from 16 July 622, the date of the Hegira. The 29th February is called an intercalary day.
In England, the new style quarter days are Lady Day 25 march, Midsummer day 24  June, Michaelmas
Day 11 october, "Old Christmas Day 6 January. Midsummer is the weekly period around the summer
solstice 21 June. The term millennium (1 000 years)  comes from St. John's gospel of the Bible and refers
to the period of a thousand years when Christ will return to earth and live with His saints and finally take
them to heaven.
2. In AD 325 the Council of Nicaea determined that Day be celebrated always on the 25th December, an
immovable feast, but Easter day remained a movable feast. Easter Day is now determined in the United
Kingdom by the Calendar (New Style) Act of  1750, as the first Sunday after the full Moon that happens
upon or next after the twenty-first day of March, and if the full Moon happens upon a Sunday, Easter Day
is the Sunday after. So Easter Sunday can be from 22 March to 25 April. Most  countries use the
Gregorian Calendar and the date of Easter used in the United Kingdom. However, Eastern Orthodox
Churches may still use the Old Style Calendar and have a different date for Easter Sunday. Their Xmas
Day is 7 January. Yule (Norse: jól) was a pagan festival for the winter solstice but nowadays Yule refers
to Christmas festivities.
3. The 21st century started in 2001 because the first century started in AD 1. The year before it was
1 B.C., so there was no "year 0". B.C. stands for "before Christ" so the years are numbered backwards.
AD stands for the Italian "anno domini", in the year of the Lord. In AD 525 Dionysius Exiguus decided on
the start of the present calendar so that Jesus Christ was born on December AD 1. Jesus Christ may have
been born as early as 4 B.C.
4. However, if Jesus was born Sunday, 1 March, 7 B.C., this was the year of the triple conjunction of the
same two planets when in 27 May, 5 October and 1 December, Jupiter moved close to Saturn in the
constellation Pisces. The conjunctions were first calculated by the astronomer Johannes Kepler in 1603.
The first conjunction may have started the magi on their journey to Israel. The second conjunction may
have guided them. The third conjunction in December may have pointed to the birth of  Jesus. However,
there was also a conjunction of Venus and Jupiter in Leo in June 2 B.C. In AD 314 Emperor Constantine
the Great changed the date of the birth of Jesus from 1 March to 25 December to be the same date as a
pagan Sun festival. The star seen in the east to guide the wise men is only mentioned in the Gospel
according to St. Matthew.
36.51 Action-reaction on roller skates
Put on a pair of roller skates and throw a large ball over the head to another student. Note the direction in
which the other student moves. Repeat the experiment with both students on roller skates.
36.52 Action-reaction engines
See diagram 36.103: Balloon boat and rocket
1. Make a balloon-powered boat. Cut away one side of a cardboard box and make a hole in the bottom
near the edge. Insert a tube into the hole and attach the balloon to it. Inflate the balloon and place the
boat in water. Note the direction the boat moves as air leaves the balloon. Repeat the experiment with
the open end of the tube under surface water.
2. Make a balloon-powered rocket. Attach a drinking straw to the side of a long balloon with adhesive
tape. Pass a wire through the drinking straw, attach each end of the wire to fence posts and tighten the
wire. Inflate the balloon then release it. The balloon travels along the wire.
36.53 Thrust experiments
See diagram 36.104: Measure thrust from a balloon with a beam balance
1. Turn on the tap and feel the thrust produced when water passes through a garden hose. Turn the tap
on more. As the amount of water passing through the hose increases, the hose begins moving in the
opposite direction to the moving water. Attach a rotary lawn sprinkler to the hose. Gradually turn on
more water and note how the speed of the lawn sprinkler increases as the amount of water increases.
2. Measure thrust with a balance. Put 50 g masses on one pan. Firmly hold an inflated balloon over the
other pan. Allow the air to escape against the pan. Note how many gm weight of thrust the escaping air
exerts on the pan.
3. Large rockets may produce 300 000 to 1 000 000 kg weight of thrust. If a rocket weighs 5 000 kg,
the Earth's gravity is pulling down on this rocket with a force of 5 000 kg weight. Before the rocket can
rise, it must overcome that pull towards the centre of the Earth so the rocket's thrust must exceed 5 000
kg weight.
36.54 Weightlessness, reference systems
See diagram 36.105: Weightless toy soldier
1. Use string to attach a toy soldier to two arms of a framework. Take the apparatus to a high building
and drop it out of the window. While falling, the toy soldier remains in the same position relative to the
framework. The toy soldier is not supported by either the string or the frame, but is in a weightless
condition with regard to the surroundings, e.g. the reference system being used. To study the motion of
an object we need a reference system, e.g. something relative to which it is possible to describe the
location of the object at any time. For many experiments we choose a reference system fixed to the Earth,
e.g. study a falling object. In such a reference system the Earth is at rest.
2. The weight of an object also depends on its location. Measured in a reference system fixed to the Earth,
the weight of an object is the same as the Earth's gravitational force acting on it. This force decreases as
the object moves away from the Earth and will eventually become negligible. The weight of the object is
changing under the above circumstances. The content of matter of the object does not change, unless
approaching that of light. An astronaut whose mass on the surface of the Earth is 90 kg still has the same
mass of 90 kg on the surface of the Moon but 90 kg weight on the Earth's surface is only about 15 kg
weight on the Moon's surface. Using SI units, the mass is m kg but the weight is mg Newton. Since g at
the Moon is about one sixth of g at the Earth, the weight of an astronaut on the Moon will be one sixth of
the weight on the Earth.
3. A spaceship in orbit is still within the Earth's gravitational field. Its weight is exactly the force required
to keep the spaceship in orbit. However, in a reference system attached to the spaceship, everything
inside is weightless.
36.55 Angle, degree, arc minute, arc second, radian
Angle is the measurement of the inclination of one line to another. An angle is usually measured in degrees,
such that 360 degrees (360o) = 1 revolution. The degree is divided into arc minutes, arcmin, such that
1' = 1 / 60 of a degree, and arc seconds, arcsec, such that 1' = 1 / 3600 of a degree. Arc minutes and
arc seconds are used in astronomy to measure the diameter or separation of astronomical objects. Also,
an angle can be measured in radians, an angle at the centre of a circle subtended by an arc equal to the
radius of that circle, such that 2π radians = 1 revolution. The "second" refers to the second division of time
into sixtieths after dividing the hour into minutes.
36.68 Sundial for the Southern hemisphere
See diagram 36.68
Place an upright metre stick in the ground so that it is not likely to be shaded from the sun. Mark the
position of the top of the metre stick on the ground at hourly intervals.
36.69 Sundial for the home
See diagram 36.69: Sundial for the Northern hemisphere
Make the base with a flat rectangular piece of wood, metal or polystyrene. The gnomon ABC consists of
a thin triangular piece of metal or plastic and such that angle ABC = latitude of the place at which the dial
is being set up and angle ACB = 90o. Use a spirit level to test that the base is horizontal. The central line
must lie along the north south line, i.e. the meridian. Erect the gnomon vertically so that the hypotenuse
points towards the Pole Star in the Northern hemisphere and the celestial south pole in the Southern
hemisphere. For approximate results, make the hour markings by noting the position of the shadow of the
gnomon at hourly intervals, using a watch set to local mean time. You can obtain more accurate results if
the markings are made on 15 April, 15 June, 1 September or 24 December, when there is no difference
between watch time and dial time. Errors of up to 16 minutes are possible if you make markings on other
dates. For accurate hour markings, find the angles the markings make with BC using the following the
formulae: tan IOC = tan 15osin lat., tan IIBC = tan 30osin lat, tan IIIBC = tan 45osin lat., tan IVBC =
tan 60o sin lat, tan VBC = tan 75osin lat., tan VIBC = tan 90o sin lat. Since the markings are symmetrical
about the central line XY you do not need to calculate other angles. If the base of the dial is erected
vertically then the angle between the gnomon and the base must equal 90o minus latitude of that place.
36.70.1 Universal globe sundial
See diagram 36.70A: Universal globe sundial
With a globe of the Earth you can make a sundial that shows the season of the year, the regions of dawn
and dusk, and the hour of the day wherever the sun is shining. The globe is rigidly oriented as an exact
model of the Earth in space, with its polar axis parallel to the Earth's axis, and with your own town "on
top of the world".
First turn the globe until its axis lies in your local meridian, in the true north and south plane. Find this by
observing the shadow of a vertical object at local noon, or by observing the Pole Star on a clear night, or
by consulting a magnetic compass, if you know the local variation of the compass, the magnetic deviation.
Turn the globe on its axis until the circle of longitude through your home lies in the meridian. Tilt the axis
around an east west horizontal line until your home town stands at the very top of the world. Now your
meridian circle connecting the poles of your globe lies vertically in the north south plane. A line drawn from
the centre of the globe to your local zenith will pass directly through your home spot on the map.
Lock the globe in this position and let the rotation of the Earth do the rest. Be patient and do not turn the
globe at a rate greater than that of the turning of the Earth. However, it will take a year for the sun to tell
you all it can before it begins to repeat its story.
When you look at the globe fixed in this proper orientation you can see half of it lighted by the sun and
half of it in shadow. These are the actual halves of the Earth in light or darkness at that moment. An hour
later, the circle separating light from shadow has turned westward and its intersection with the equator
having moved 15o to the west. On the side of the circle west of you, the sun is rising, on the side east of
you, the sun is setting.
You can count the hours along the equator between your home meridian and the sunset line and estimate
how many hours of sunlight remain that day. Look to the west of you and see how soon the sun will rise
there. As you watch the globe day after day, you will become aware of the slow turning of the circle
northward or southward, depending upon the time of year.
36.70.5 Build a sundial
See diagram 36.70.5: Horizontal sundial
The gnomon is the part of the sundial that produces the shadow. The top edge of the gnomon must slant
upward away from the base, or horizontal, at an angle equal to the latitude of the observer and towards
the South for an observer in the Southern hemisphere. The gnomon must be aligned along the N-S
meridian. The hour lines are marked on the other part of the sundial, called the time plane. The
configuration of the gnomon and the time plane identifies the type of sundial that has been constructed.
In the diagram, the shaded area represents a sundial. The top edge of the gnomon is parallel to the Earth's
 axis and the angle, gamma, between the top edge of the gnomon and the horizontal is equal to the latitude
of the observation site. A horizontal sundial has the hour lines are marked on a time plane horizontal to the
Earth's surface. You can use the data in Table 3 to construct your horizontal sundial. The table contains
hour angles for some cities and towns in Queensland, Australia, calculated by using spherical trigonometry.
Note how the hour angles vary with latitude.
Table 3: Hour angles for the horizontal sundial
Time a.m. Time p.m. B R M T C T L M
11 hours or 13 hours 07.0 06.1 05.5 5.0 07.5 07.1 06.1 05.4
10 hours or 14 hours 17.8 12.9 11.7 10.8 09.5 13.0 12.9 11.5
09 hours or 15 hours 27.6 21.7 19.8 18.2 16.2 27.9 21.7 19.4
08 hours or 16 hours 38.4 37.5 31.9 29.7 26.7 38.8 37.5 31.4
07 hours or 17 hours 59.7 56.0 53.3 50.8 47.3 60.0 56.0 52.7
B = Brisbane, R = Rockhampton, M = Mackay, C = Cairns, T = Toowoomba, L = Longreach, M = Mt. Isa
On a square sheet of cardboard draw a line perpendicular to one edge to represent the 12h 00 m hour
line. Use a protractor to draw lines spreading out from the 12h 00 m hour line at the angles in the table if
you are in one of the places in Table 3. If you live in Queensland outside these places, find out the latitude
of your place and estimate the hour angles, e.g. the hour angle corresponding to 11 AM and 1 PM for
Maryborough would be somewhere between 7.0o (Brisbane) and 6.1o (Rockhampton). Label the hour
lines as in the diagram. Use another piece of cardboard to cut out the gnomon with one angle equal to the
latitude of your location. Attach the gnomon to your sundial base along the 12h 00 m hour line with the
angle equal to your latitude pointing North. The angle shown in Figure 3 is the latitude of  Brisbane. Align
the gnomon along the N - S meridian.
36.70.6 Pocket sundial
Cut a wire coat hanger in half and set the angle to the latitude of your location. Attach the coat hanger to
a cardboard base marked with the hour lines and align the gnomon north south. Use the sundial to
investigate the altitude of the sun and the passage of time during the day. Maintain daily records of the
progress of sunrise and sunset to the North and South.
36.70.7 Parallel rays of the sun
BE CAREFUL! DO NOT LOOK AT THE SUN THROUGH THE TUBE AS DIRECT SUN RAYS
CAN DESTROY THE RETINA OF YOUR EYE.
1. To show that the sun's rays are parallel as they fall on the Earth, on a bright morning, point a piece of
pipe or a cardboard tube at the sun so that it casts a small, ring-shaped shadow. If at the same moment a
person 120o east of you, one third of the way round the world, performs the same experiment, that person
points the tube westward at the afternoon sun. Yet that tube and yours approximately parallel. If you
point the tube at the sun in the afternoon, and someone far to the west simultaneously does the same in the
morning, that tube will approximately parallel to your tube. So when your globes are properly set up,
people all over the world who are in sunlight will see them illuminated in just the same way.
2. You can tell from the global sundial how many hours of sunlight any latitude receives on any particular
day. Count the number of 15o longitudinal divisions that lie within the lighted circle at the desired latitude.
Thus, at 40o north latitude in summer the circle may cover 225o of longitude along the 40th parallel,
representing 15 divisions or 15 hours of sunlight. However, in winter the circle may cover only 135o,
representing nine divisions or nine hours. As soon as the lighted circle passes beyond either pole, that pole
has 24 hours of sunlight a day, and the opposite pole is in darkness.
36.76 Constellarium
1. A constellarium is a simple device used in teaching the shapes of various constellations. Use a
cardboard or wooden box and remove one end. Draw the shapes of various constellations on pieces of
dark-coloured cardboard large enough to cover the end of the box. Punch holes on the diagrams where
the stars are located in the constellations. Place an electric lamp inside the box. When the lamp is turned
on and various cards are placed over the end of the box, the constellations may be seen clearly.
2. Another way is to obtain several tin cans into which an electric lamp may be fitted. Holes are punched
in the bottoms of the cans to represent the stars in various constellations. When the lamp is placed inside
a can and switched on, the light shows through the openings and the shape of the constellations may be
observed. The tin cans may be painted to prevent rusting and kept from year to year.
36.76.1 Umbrella constellarium
See diagram 36.76Bd: Northern hemisphere, Southern hemisphere
Since an umbrella has the shape of the inside of a sphere, it can be made into a constellarium that will
illustrate portions of the heavens and how they move. You will need an old umbrella that is large enough
for this purpose.
Northern hemisphere
Using chalk, mark the North Star, or Polaris, next to the centre on the inside of the umbrella. Consult a
star map, and mark the star positions for various constellations with crosses. When you have filled in all
the polar constellations, you can paste white stars made from gummed labels over the crosses, or you may
paint the stars in with white paint. Later you can draw dotted lines with white paint or chalk to join the
stars in a given constellation. If the handle of the umbrella is rotated in a counter clockwise direction, you
will see how the various stars trace a circular path about the Pole Star.
Southern hemisphere
South of the equator, the umbrella should be pointed towards the southern celestial pole and we will
therefore have to turn it clockwise. As in the Northern hemisphere, the stars will rise in the east and set in
the west. In the diagram above you can see some of the more prominent stars and constellations marked
on the umbrella.
36.77 Seasonal shift of the sky
As the Earth travels in its orbit around the sun the constellations seem to move across the sky. The
materials required for observing the shift are a star chart and a plumb line. Make only one set of
observations and record the time. At least one month later, repeat the same observations in the same way,
at as nearly the same time of night as possible. Compare the two observations made at the same time of
night and note what change do you see in one month. Calculate how much change would occur in one
year, if the same rate continues. Answer the same questions for the Big Dipper and North Star, if you are
north of the equator or for the Southern Cross if you are south of the equator.
36.78 Time and date using the stars
Because the stars appear to rotate one full revolution in 24 hours, they can be useful in telling time, at least
during those hours of darkness when the stars are visible to us. Because the stars also make one full
revolution in a year, they can be used to tell us the time of the year. And so we have not only a star clock,
but also a star calendar.
36.78.1 Star calendar
See diagram 36.78BN: Northern hemisphere
See diagram 36.78BS: Southern hemisphere
The dates round the edge of the star chart for the Northern hemisphere show when the corresponding
part of the heavens is due north at midnight. For the Southern hemisphere the dates show the part which
is due south at midnight. Knowing this you can easily rotate the star map so that it corresponds to what
you see in the sky. If you are north of the equator and you have to rotate the map 15o clockwise from the
midnight position, the time is 1 a.m., if you have to rotate it 30o counter clockwise, the time is 10 p.m.
South of the equator it is the other way round since you are facing south. If you have to turn the map 15o
clockwise from the midnight position it means that the time is 11 p.m. The times determined this way are
sun times and they may differ from your local standard time.
36.78.2 Star clock
Separate sets of diagrams are given below for the northern and Southern hemispheres, one clock for each
month. The nine o'clock positions of the star clock's hand are marked of f at the middle of some months.
Can you fill in the nine o'clock positions for May, August and November? Try to fill in midnight positions
for June, September and December. In the Southern hemisphere, locate roughly the southern celestial
pole.
36.91 Star trails in colour
The stars are as colourful as land subjects, but this is not generally known because dark adapted eyes
have low sensitivity to colour. High speed colour film and a camera with at least an f 3.5 lens will record
the red star Betelgeuse in the constellation Orion, the yellow star Capella in the constellation Auriga, and
the gold star Albireo in the constellation Cygnus. The constellation Cassiopeia contains two blue, one
white, one golden, and one green star. A good camera that can make time exposures, a rigid tripod, and
fast film are all you need. The simple star charts in this book will help you to identify the constellations.
Your local public library may have books on amateur astronomy which contain similar charts. Dial
indicators that show all the constellations overhead when the dial is set for the month, day, and hour, are
also obtainable in some countries.
The Earth rotates 15o per hour, or 10 every 4 minutes. To us on the Earth, it is easier to appreciate this
movement by assuming that the stars move. Furthermore, the stars appear to rotate around your celestial
pole. Each star near the pole traces a tight circle in its movement, and as the distance from the pole
increases, the radius of curvature increases until the stars above the equator appear to travel in straight
lines. A star is a true point source of light and no movement of the camera can be tolerated unless you
want pigtails for star images. All trouble can be avoided if you mount your camera on a rigid tripod, cover
the lens with a cardboard, use a long cable release to open the shutter on time or bulb, wait 3 seconds or
so for the camera to stop moving, and then remove the cardboard from in front of the lens. At the end of
the exposure, again cover the lens with a cardboard before closing the shutter. Commercial processing
laboratories will probably not recognize star images for what they are and, unless you instruct them
otherwise, will return your negatives unprinted.
36.92 Photograph constellations
See diagram 36.92: Old 35 mm slide used for teaching about constellations
1. Photographs of constellations add an aesthetic purpose to photographing star trails. The results make
beautiful prints and slides in both black and white and colour, and they prove to be a very effective
teaching medium. There are many techniques for photographing constellations, but a favourite is as follows:
select a particular constellation, set up the camera, and expose for 30 minutes with high speed black and
white film, 400 ASA and a lens opening of f 11, then cover the lens for 2 minutes, open it to f 4, and
throw it slightly out of focus, finally, uncover the lens for 3 more minutes. A diffusion screen over the lens
for the final exposure works just as well as throwing the lens slightly out of focus. The resulting picture
shows a constellation that appears to be plunging through space with a tail following each star.
2. Underexposed and discarded 35 mm film slides can be perforated with a pinpoint in the form of
various constellations. The slides can be projected on to a screen or used in a viewer, and students can
try to identify the constellations. The slides can also be dropped into a slot made in a mailing tube and
held up to the light.
36.93 Photograph satellites
Satellites are a joy to photograph. Use the same camera technique as for star trails, see above. Kodak
Tri-X Pan film is an excellent choice. Use Kodak HC-110 developer, diluted 1: 15 at 24oC for 4
minutes. The main problem is to know ahead of time where to aim your camera. There are several
sources for this information. Many newspapers publish daily the times, the degrees above the western or
eastern horizon, and the direction of travel for all visible satellites. Also, local astronomical observatories
and amateur astronomical clubs may be able to furnish the required data for you. Satellite photography is
particularly rewarding when the satellite path crosses a well known constellation, or if you are extremely
lucky, perhaps two satellites will cross within your photograph. It is this unknown factor that continues to
attract the amateur, as well as the professional, astronomical photographer.
36.94 "Twinkle, twinkle little star"
Twinkling star (stellar scintillation, astronomical scintillation) is cause by refraction of light from stars as the
light is refracted when moving though different layers in the atmosphere with differing densities. Star close
to the horizon twinkle more because the light from them has passed through more atmosphere. Planets
appear bigger than stars so any twinkling effect is not usually noticeable.
"Twinkle, twinkle little star" is the first line of a poem published in 1806, "The Star" by Jane Taylor, of
Ongar, England.
36.101 Spectroscope for materials analysis, shoe box spectroscope
See diagram 36.101: Shoe box spectroscope | See 4.134: Diffraction grating, spectroscope
By using a sensitive instrument called a spectroscope, scientists are often able to analyse the composition
of materials located a great distance away. The spectroscope has been used to determine the
composition of the sun and other stars and of the atmosphere of many of the planets. Spacemen in the
future will use this kind of device to analyse the chemical composition of their immediate surroundings.
Light entering a spectroscope is split up by a diffraction grating to form coloured bands, which we call a
spectrum. Since each chemical element shows certain characteristic bright shoe box spectroscope lines in
its spectrum the material can thus be easily identified. The materials required are a shoe box, replica
grating, see science supply catalogues, some masking tape, and a double edged razor blade broken in two.
Cut a hole of about 2 cm diameter in the middle of one end of the box. Use tape to fix a piece of replica
grating over the hole from the inside. Cut a 2.5 cm × 0.5 cm slit, which should be parallel to the lines of
the grating, in the middle of the other end. Cover the slit from the outside with a finer slit made from two
halves of a razor blade, edges facing each other. The two halves are held together and fixed to the box
with tape. The width of the slit should be about the same as the thickness of a razor blade and is finally
adjusted for the best results, see diagram. Look through the spectroscope at various luminous gases such
as neon and argon in lamps or signs. Notice the bright lines in the spectrum, which indicate that each
element has its own pattern.
36.101.1 Atomic absorption spectroscopy
AAA, is used for determining the composition of inorganic elements in a sample. AAS works on the
principles of atomizing a sample and quantitatively determining the concentration of atoms in the gas phase
by measuring the intensity of light absorbed by them when they are irradiated with electromagnetic
radiation. A key aspect of AAS is the method used to atomize the sample, which also affects the
sensitivity of the technique. Methods include flame, graphite furnace, electro-thermal, plasma furnace, and
vapour-hydride atomization. Chemicals prepared for AAS work are called AAS solutions.
36.106 Satellite launcher
See diagram 36.106: Simulated satellite launcher
Materials required are a bucket, a football, a coat hanger, or other suitable wire, sinker or weight, a piece
of string and a test-tube or a cap of some sort. Place the ball securely in the bucket. Bend the wire so that
about 30 cm of it is straight and the rest is curved into a circular base as shown in the sketch. Using
masking tape, secure the circular portion on the ball, allowing the straight, 30 to stand upright in the
centre of the top of the ball. Attach the sinker or weight to the string. Fasten the other end of the string to
the test-tube or cap with tape. Invert the cap on top of the upright wire, see diagram. Explain that the
ball represents the Earth, and the sinker represents the satellite. All that it takes to set the sinker into
motion in any direction is the tap of a finger. Let the students find out what happens when the satellite is
launched in the following different ways:
1. With a slight tap, push the sinker up and away from the surface of the ball, as shown in the figure. The
sinker moves up and then falls back to the starting point. This is how an object travels when it is projected
at low speed straight up from the Earth.
2. With a slight tap, push the sinker of f the surface of the ball at an angle. Show by a diagram what
happens. The sinker moves away from the ball and then falls back at some distance from the starting
point. The distance spanned depends upon the angle of launching and upon the forcefulness of the tap.
3. With a stronger tap, push the sinker of f the surface of the ball at an angle. Make a diagram of the orbit.
The sinker moves away from the ball, circles it, and lands. Evidently, a complete orbit passes through the
starting point of the orbit.
36.107 Kepler's laws of planetary motion (Johann Kepler 1571-1630)
1. The orbit of a planets is an ellipse, with the Sun at one focus of the ellipse.
2. Each planet moves such that a line connecting the planet to the Sun would sweep equal areas in equal
times.
3. The ratio of the square of the time of planetary revolution (sidereal period) to the cube of its distance
from the Sun is constant for all planets.
1. Each planet orbits in an elliptical path, with the Sun at one focus.
2. A line joining the Sun and any planet sweeps out equal areas in equal time intervals.
3. The squares of the orbital periods of the planets are proportional to the cube of their mean distances
from the Sun. The ratio r3 / T2 is the same for all planets, where r is the mean orbit radius, and T is the
period of revolution. For all satellites of the Sun, r3 / T2 = 3.3 × 10-18m3 / sec2.
36.108.01 Newton's universal law of gravitation, gravitational constant, G
1. The universal law of gravitation states that any two particles of matter attract each other with a force
directly proportional to the product of their masses and inversely proportional to square of the distance
between them, d or r. The force of gravitational attraction, Fg = G × m1m2 / d2 or G × m1m2 / r2
where Fg in newton, m = mass of a particle in kilograms, d or r = distance between the particles in
metres, and G = the gravitational constant.
The gravitational constant, G = 6.67259 × 10-11 Nm2kg-2 = 6.67 × 10-11 newton.m2/ kg2
2. The universal law of gravitation states that every object in the universe attracts every other object in the
universe with a force that varies directly with the product of the masses, and varies inversely with the
square of the distance between the centres of the two masses.
So Fg = G (m1 × m2) / r2, force, where Fg in newton, m in kilograms, r in metres, and universal
gravitational constant, G = 6.67 384 × 10-11 N m2 / kg2.
36.108.02 Weight of an object and g
The weight of an object is the force of gravity on that object and is measured in newton, N.
The weight of an object on the Earth, W = Fg = G × mMe / Re2, where m = mass of the object in
kilograms, Me = mass of the Earth in kilograms, Re = radius of the Earth in metres.
So weight, W = m × G × Me / Re2. The gravitational field of the Earth at that place, g = G × Me / Re2.
36.108.03 Gravitational field of the Earth, g, gravitational constant, G
Near the surface of the Earth, the gravitational field of the Earth, g = 9.8 N / kg acting towards the centre
of the Earth.
The weight of an object, W = mg newton, where g = G × Me / Re2 newton / kg.
The magnitude of g diminishes as you get further from the Earth because r increases in the equation,
F = G (m1 × m2) / r2.
The gravitational constant, G = 6.67 384 × 10-11 m3 kg-1 s-2, N m2 / kg2.
36.108.04 Satellite in stable orbit, geostationary orbit
For a satellite to remain in a stable circular orbit around the Earth at a fixed radius, rs, the required
centripetal force, Fc, must be supplied by the gravitational force, Fg. So Fg = Fc = G × ms Me / r2
= ms 4pi2rs / Ts2, where ms = mass of satellite and Ts = the period of revolution of the satellite.
36.109 Gravitational potential energy
1. The energy an object possesses because of its position in a gravitational field is called its gravitational
potential energy. On the Earth the gravitational acceleration is about 9.8 m / s2. The potential energy of an
object at a height h above the ground = the work required to lift the object to that height. The force
required to lift the object = its weight, so gravitational potential energy = the weight of an object × times
the height it is lifted. In space, the force approaches zero for large distances. so the gravitational potential
energy near a planet is negative because gravity does positive work as a mass approaches. The small
mass approaching the large mass of a planet it bound to it unless it can get access to enough energy to
escape. The general form of the gravitational potential energy of mass m is: PE = -GM1m2 / r,
G = the gravitation constant, M = mass of the planet, m = mass of the approaching object, r =
distance between the centres of the planet and the approaching object
2. An object of weight W = mg newton can be raised to a height by either (a) lifting it vertically or
(b) pushing it up a frictionless ramp.
2.1 By applying a force equal and opposite to the weight, the object could be lifted directly through the
height Work done = force × height = mg h joule. Increased gravitational potential energy of the object at
height h = mg h joule.
2.2 By applying a force equal and opposite to the component of the weight acting down the slope, the
object could be pushed up the slope. Work done = force × distance up the slope =
(weight × sin angle of slope) × (height / sin angle of slope) = mgh joule.
The method of raising an object vertically, or via any ramp, does not change the amount of work required
to be done, and does not change the increase in gravitational potential energy, Ep = mgh joule.
3. On the surface of the Earth, the weight of an object is constant, and any change in gravitational
potential energy depends on mass, g (constant at the place) and height, Ep = mgh joule. However, a
satellite launched from the Earth has a changing gravitational force on it, falling to zero at infinity.
Gravitational binding energy is the extra energy an object needs to escape from the Earth. A mass on the
Earth's surface must be launched with sufficient kinetic energy, EK, to overcome the binding energy and
escape from the Earth. Escape velocity is the velocity needed to escape and is the same for all masses of
objects. If a satellite is given just enough energy to escape from the Earth, it will remain in the Earth's orbit,
but on the opposite side of the Sun from the Earth. The farthest the satellite can escape from the Earth
without escaping from the Sun is in the Earth's orbit on the other side of the Sun. The orbiting satellite
needs extra energy to escape from the Sun.
36.110 Mass, inertial mass and gravitational mass
See 6.3.1.2: Mass, kilogram
The standard of mass is the kilogram, based the existence of a particular cylinder of platinum-iridium
alloy. This standard can be referred to as the inertial mass, mi.  So mass is defined by its inertia. However, 
mass is conveniently measured by using the weight, W, of the body, i.e. the force of gravity attracting it
to the earth. W = mg, where g is the acceleration of fall that varies slightly in different places on the
surface of the earth.
To define mass in terms of the gravitational force it can produce, i.e. gravitational mass, mg, use the
formula: mg = Fd2 / MG, where M is a standard body distance d from another body of mass mg, F is the
gravitational force between the bodies and G is the universal gravitational constant. However, mi = mg.
36.111 Earth rotation and wind farms
It is unlikely that the construction of wind farms affects the rotation of the earth. The relative forces are not
comparable. Some people have suggested that half the wind farms could face east and the other half face
west to counteract any effect on the rotation of the earth!
36.112 List of constellations
Latin name, English name
Andromeda, Andromeda
Antlia, Air Pump
Apus, Bird of Paradise
Aquarius (in the Zodiac), Water Bearer
Aquila, Eagle
Ara, Altar
Aries (in the Zodiac), Ram
Auriga, Charioteer
Bootes, Herdsman, contains Arcturus
Caelum, Chisel
Camelopardalis, Giraffe
Cancer (in the Zodiac), Crab
Canes Venatici, Hunting Dogs
Canis Major, Great Dog
Canis Minor, Little Dog
Capricornus (in the Zodiac), Sea Goat
Carina, Keel
Cassiopeia, Cassiopeia
Centaurus, Centaur
Cepheus, Cepheus
Cetus, Whale
Chamaeleon, Chameleon
Circinus, Compasses
Columba Dove
Coma Berenices, Berenice's Hair
Corona Australis, Southern Crown
Corona Borealis, Northern Crown
Corvus, Crow
Crater Cup
Crux, Southern Cross
Cygnus Swan
Delphinus, Dolphin
Dorado, Swordfish
Draco, Dragon
Equuleus, Little Horse
Eridanus, River Eridanus
Fornax, Furnace
Gemini (in the Zodiac), Twins
Grus, Crane
Hercules, Hercules
Horologium, Clock
Hydra, Sea Serpent
Hydrus, Water Snake
Indus, Indian
Lacerta, Lizard
Leo (in the Zodiac), Lion
Leo Minor, Little Lion
Lepus, Hare
Libra (in the Zodiac), Scales
Lupus, Wolf
Lynx, Lynx
Lyra, Harp
Mensa, Table
Microscopium, Microscope
Monoceros, Unicorn
Musca, Fly
Norma, Level
Octans, Octant
Ophiuchus, Serpent Bearer
Orion, Orion
Pavo, Peacock
Pegasus, Winged Horse
Perseus, Perseus
Phoenix, Phoenix
Pictor, Easel
Pisces (in the Zodiac), Fishes
Piscis Austrinus, Southern Fish
Puppis, Ship's Stern
Pyxis, Mariner's Compass
Reticulum, Net
Sagitta, Arrow
Sagittarius (in the Zodiac), Archer
Scorpius (in the Zodiac), Scorpion
Sculptor, Sculptor
Scutum, Shield
Serpens, Serpent
Sextans, Sextant
Taurus (in the Zodiac), Bull
Telescopium, Telescope
Triangulum, Triangle
Triangulum Australe, Southern Triangle
Tucana, Toucan
Ursa Major, Great Bear, Charles's wain
Ursa Minor, Little Bear, Cynosura, Dog's tail (the pole star is alpha in the tail)
Vela, Sails
Virgo (in the Zodiac), Virgin
Volans, Flying Fish
Vulpecula, Fox
36.113 Inservice training, The Sun and the Earth
Equipment
1. Paper
2. Double sharpened pencil, board, adhesive tape, pencil, NS compass, hole gnomon, examples of
shadows, tape measure, clipboard
3. Stake, string, wire markers, mallet
4. Magnifying glass, absorbent paper
5. Metal barrier with hole, spanner, electric light stand for artificial sun
6. Mirror, plastic trough, water, screen
7. Pinhole viewers
8. Binoculars, white board, sunspot photograph
9. Ball in plastic bags, string
10. Earth orbit machine
11. Balloons, felt pens
36.113.1 Sun, our Sun is a star
1. How the Sun works, fusion reaction, energy, temperatures
2. Different layers, internal, photosphere, chromosphere, corona
3. Magnetic fields, sunspots, prominences, filaments, solar flares
4. Sunspot cycles and effects
5. The influence of the Sun on the Earth, light, heat, magnetic storms
6. Spectrum and the visible colours, the types of energy emitted by the sun
7. The solar system and our place in it, planetary orbits, earth moon system, nature of the moon, e.g. no
atmosphere, moon phases
8. Danger of the Sun's rays, risk to eyesight in unprotected viewing due to intense light and IR
9. Never look at the Sun with eyes, magnifying glass, sunglasses, binoculars, telescope, burnt glass.
10. Never stay in the Sun if your shadow is shorter than you.
36.113.2 Measurements using the Sun
1. Compare the lengths and directions of the shadow at noon to other times, shadow of a Sundial gnomon,
pencil gnomon, hole gnomon (rectangular piece of metal with a round hole in it)
2. Join two positions of the shadows over 15 minutes of a 2 metre long stake to show east west direction.
3. Focus the Sun's rays, focus the light from the Sun on a screen, focus the heat from the Sun to burn
paper.
4. Area of sun's radiation on tropical or polar regions
5. Use refraction through water to separate colours in the Sun's rays to form separate colours on a screen.
6. Use a pinhole camera Sun viewer to view an image of the sun.
7. Use binoculars to view an image of the Sun.
8. Use the Earth orbit machine and see the seasons in the Southern hemisphere and Northern hemisphere.
36.113.3 Measurements using the Earth
1. Mark an earth balloon to show the equator, the standard meridian through Greenwich, the International
Date line, the Tropics of Cancer and Capricorn.
longitude and latitude. Brisbane: Latitude: -27o28', Longitude: 153o1'.
2. Longitude is measured in degrees up to 180o (right ascension). Usually, each geographic time zone
within a country differs by 15o of longitude = 1 hour.
3. The equator is the great circle that divides the earth into Northern hemisphere and Southern
hemisphere. Tropics are parallels of latitude 23o26' north of the equator, the tropic of Cancer or south of
the equator, the tropic of Capricorn. North of the equator, the tropic of Cancer marks the most northerly
declination of the Sun at the summer solstice, about 21 June. The declination is the angular distance of a
celestial object north or south of the celestial equator. Positive towards the north celestial pole and
negative towards the south celestial pole. South of the equator, the tropic of Capricorn marks the most
southerly declination reached by the Sun, about 22 December.
4. Tilt of the earth's axis 23.44o
See diagram 15.0.4.1: Axis of rotation of the Earth
The angle between the axis of rotation and the pole of its orbit is called the obliquity of the ecliptic, about
23o26' and decreases by about 0.47' per year. Also it is defined as the angle between the plane of the
ecliptic and the celestial equator. For half the year the Sun is in the Northern hemisphere in the sky and
half the year in the Southern hemisphere.
5. Path of the earth is east to west rotation, counter clockwise.
36.113.4 Preparation for the Total Solar Eclipse in 2012
The mechanism of eclipses
1. The sun moon apparent size comparison
2. How solar and lunar eclipses occur
3. Types of solar eclipses, total, annular, hybrid, partial
4. Lunar eclipses, partial and total
5. Why eclipses do not occur every month
6. Modern eclipse prediction and Saros cycles
The experience of a total eclipse
1. Moon shadow, twilight sky, horizon colours
2. Partial phases, diamond ring, Bailey's beads, shadow bands
3. Chromosphere, prominences
4. Corona and corona pattern, what to expect in 2012
5. Difference if inside or outside the shadow path
5. Possible wonderful demonstrations of celestial mechanics
Safe solar viewing
1. Damage from unprotected solar viewing
2. Complementary to sun safe messages
3. Pinhole projection and optical projection
4. Solar (white light) filters and hydrogen α filters
5. "Eclipse glasses" and demonstration of how to use safely
6. Sate to view eclipse during totality
The scientific aspect of eclipses
1. The primitive view
2. Scientific study of the sun, including helium
3. Proof of relativity
4. Ongoing study of inner corona
5. Other solar event will be transit of Venus in June 2012 and an annular solar eclipse
in North Queensland in May 2013
School projects
1. Eclipse models, sun, earth and moon; model of solar and lunar eclipse
2. Pinhole projectors, construct and test before eclipse, every student in the eclipse totality, path of
transit of Venus, path of annular eclipse to have a pinhole projector
3. Optical projectors, telescope, binoculars, simple magnifying lens, buy or borrow a "Solarscope"
4. Eclipse observation, timing of contacts and compare with predictions, observe each effect, e.g. Bailey's
beads, corona, sketch the corona and note magnetic influence, temperature measurement, light and colour
changes, meteorological effects, animal influences, photography
5. Eclipse prediction, use of computer or graphical tools from web or software, prepare local
circumstances for your observations
6. CSIRO projects, sunspot recording, sundials.
36.113.5 Transit of Venus
The transits of 1761 and 1769 and later at 1874 and 1882  provided a way of measuring the distance
between the Earth and the Sun. This was the key distance that astronomers needed to work out the scale
of the Solar System and to establish the distances to the nearest stars. The idea was to time the instants
when Venus just appeared to touch the inside edge of the Sun at the beginning and at the end of the
transit. If the timing could be done accurately astronomers could compare observations from widely
separated places and determine  the distance by simple trigonometry, Captain James Cook, who
observed the 1769 transit from the Pacific island of Tahiti, was despondent because his times differed
slightly from those of the two other observers with him. He was not to know that observers elsewhere in
the world had experienced similar problems and the observations from Tahiti were better than most.
After completing the necessary observations in Tahiti, Cook opened sealed orders to search for "Terra
Australis Incognita" or the "Unknown Southern Land".
A  new transit of Venus will occur on Wednesday 6 June (5 June in the USA). As the following transit is
not until 2017, this will be the last opportunity for many to see one of the rarest and most famous
astronomical events. Australia and New Zealand will be among the best places from which to view the
2012 transit as, clouds permitting, it will be visible from beginning to end from most of the two countries.
From Sydney the transit begins at 8:16 am and ends at 2:44 pm AEST with similar times elsewhere in
Australia, and New Zealand, after allowing for different time zones. From Perth the transit will already be
 in progress at sunrise. The entire transit will also be visible from New Guinea, Japan, Korea and the
eastern parts of China and the Russian Federation. It will also be fully visible from Hawaii and Alaska,
 while from the rest of the USA the transit will still be in progress at sunset. From Europe (apart from
parts of Spain and Portugal), the Middle East, eastern parts of Africa, India and Indonesia the transit will
already be in progress at sunrise.
It needs to be emphasized that looking at the Sun is highly dangerous. Serious and irreparable eye
damage
can occur from viewing the Sun with the unaided eye or, even worse,
through binoculars or a telescope. For safe viewing go to your nearest public observatory such as Sydney
Observatory or check whether a local amateur astronomy group has arranged a public viewing of the
event.
History of experiments in this document
Astronomy and space science experiments (this document) is a revision, updating and expansion of the
New UNESCO source book for science teaching, UNESCO, Paris, Third impression 1979,
ISBN 92-3-101058-1 by Dr John Elfick, School of Education, University of Queensland, Australia
assisted by Mr R. Smith, Central Queensland University, Australia, working under UNESCO contract
8347201. The first stage in the editing process was done in China and was published in Chinese as
"GUOWAI ZHONGXUE SHIYAN DILI (Overseas Middle School Experiments, Geography) J. Elfick
editor Authors: Lin Peiying and Zeng Hongying, Capital Normal University Press, Beijing, December
1996 ISBN 7-81039-805-9 / G.662 Price Yuan 7.50. The difficult work of co-ordination and
interpretation was done by UNESCO Assistant Programme Officers Mr Howard Jiang and Ms Ye Mai.
The publication was used for inservice training and was thoroughly reviewed by geography teachers in
China. This book was on the Ministry of Education, People's Republic of China "All China Approved
Book List for primary and Secondary Schools" and is on sale to the public in China. This book was
designed to give a wider choice of experiments to teachers of geography in Chinese middle schools. The
amount of descriptive detail in the experiments is designed to be the minimum needed for doing the
experiment by a trained geography teacher. Each experiment is thought to be one of the simplest and least
expensive ways of displaying the concept. However, a teacher should check the experimental details in a
geography text recommended for use in that school system.