School Science Lessons
1. Resources for physics teaching, equipment, resources, social environment,
daily life, natural world
2011-12-25
Please send comments to: J.Elfick@uq.edu.au
Table of contents
1.0.0 Resources for physics teaching
1.5 Equipment and support systems
1.4 Physics experiments
1.0 Resources for physics
teaching and their application
1.2 Social environment of students
1.3 The daily life of students
1.1 The natural world
1.0 Resources for physics
teaching and their application
Physics is the study of what the world is made of, how it works, and why
things in the world behave in the way they do. The best resources for physics
teaching are physics experiments that have a clear aim and have been prepared
in a physics laboratory preparation room. However, this is not enough for
educating high school students. Physics becomes attractive and interesting
to them only if their learning from nature, their social environment and their
firsthand experiences as students are combined with theoretical physics teaching.
Only then can they master the methods of physics and understand the relationship
between physics and human society.
1.1 The natural world
1. Students have accumulated abundant experiences of the natural world
since childhood. These experiences and their understanding of the mysteries
of the natural world produce a great impact on their learning interest in
the method and content of physics. You must give your attention to how to
apply the experiences and understanding of students to physics teaching. Many
interesting investigations may be based on careful observation of the wind,
rain, thunder, electricity, frost, snow, dew, and hail, and lead to further
thinking. For example, the falling motion of rain, snow and hail differ so
that their shape, volume, speed and harm to plants differ. You may observe
that the rainwater on the sunken part of a lotus leaf and dew remaining on
the pine needle and grass blade can have different shapes. If you observe
the substances attached to by frost and dew, you may wonder why they "prefer"
to attach to branches and blades of grass and even hair but not the earth.
2. Of course you should be clear about the basic
questions, e.g. whether the lightning flash bolt is seen just when you hear
the thunderclap. However, further thinking is more significant if students
can study or find out for themselves. For example, how do clouds become
charged? Are there clouds with no charge in the sky? Do cyclones form like
a vortex? Why does rain form like a screen but hail form in a line? Perhaps
the physical surroundings have wider usage to physics learning of students.
Flowers, grass, trees, woods, mountains, stones, earth, sand, mud, river
and air in the natural world are all resources for mastering physics knowledge
through observing and testing. They may make students feel the profundity
of sciences. You may reach completely different conclusions if you feel the
temperature of tree and rock by touching with a hand then measuring in hot
summer and cold winter. If you try to pull a dried little tree out of the
earth, you may be ashamed of your lack of strength! You will find that their
roots cannot grasp stones under ground. It may help students to know how
friction and plants prevent water and soil from moving. In summer, forests
or caves are always cooler than outside as if independent of the flowing
hot air around them or outside. The temperature difference of sand in the
morning and evening is different from that of pool water. By simple measurement
of temperatures at these places, students may more vividly comprehend density,
pressure, specific heat, convection and climate. Walk on the earth, sand
and mud wearing different shoes and simulate a short ski. Try to touch sand
grains or pebbles in water according to the position and depth as seen from
the bank. Encourage students to do such experiments that you can accomplish
with few tools or equipment. They may provide unexpected help for students
to learn physics.
3. Many physics questions appear in the natural
world. When throwing two pebbles with different weight simultaneously onto
a river, one of them may bounce farther than the other. Spray produced by
pebbles seems no longer transparent but white. Different sprays fly up with
different heights and fall down at different positions. Smaller spray may
fly up higher and fall down farther. Waves caused by pebbles falling into
water spread as concentric circles and interference may also occur. The
waves will spread farther and the waves will not take away anything but
leaves and twigs remain floating on the water. So many phenomena are helpful
preparation for students to learn and apply much physics knowledge such
as kinematics, dynamics, optics and theory about fluctuations. While observing,
you should energetically advocate the finding of questions and using applied
learned knowledge. For example, consider a big tree growing slanting from
the bank of a river. Why does it not fall down? Is its centre of gravity
still at the area of its root support?
4. Consider the animals around us in nature. By
carefully watching a duck swimming in a river, you can find that the duck
moves ahead just by pulling water backwards and that duck feet have different
shapes when the duck pull water backwards and when they return ahead. You
relate this change in ducks' feet to the force acting on them and the structure
of their bones. By observing the eyes of a cat in the sunshine and dark,
you can observe the effect of apertures. The call of frog, cricket and rooster
can give us examples of vibration producing sound although you may not hear
some vibrations, e.g. vibration of wings of bee, mosquito and dragonfly as
they fly. Sharp teeth and claws of carnivores and sharp beaks of birds can
all exert great pressure. If you hold a cat standing then remove your hands,
you will find that it puts out the sharp claws previously hidden to try to
increase pressure to seize your clothing or body. Observe a squirrel walking
freely on thin branches. You can find that its beautiful and thick tail adjusts
distribution of its body mass at any moment just like a long pole held in
the hands of a player walking on a steel wire. By taking note of biological
development you will again get more vivid examples for teaching.
5. To sum up, when you go into the natural world,
material helpful to physics teaching may be found everywhere if you observe,
think and experiment. It is also the same in the sky or universe. Consider
the moon for example. Physicists must spend some effort to deal with questions
about the moon, questions about its change in shape, ascending and declining
around the earth, hiding briefly during lunar eclipse, reflecting sunshine
but not warm. Why does it not fall on the ground like an apple? These questions
arise only after daily observation. More embedded questions exist. For example,
they might have made an error of 1000 metres from the landing spot, unacceptable
in space science, if they launched a space ship to the moon using the standard
metre rulers of the Paris Metrology Bureau as the length benchmark. They
needed a new length benchmark. Nature provides a great deal of interesting
materials for physics teaching just as it provides boundless opportunities
for research.
1.2 Social environment of students
1. In the natural world, many non-natural things around students may become
resources for physics teaching. Observation of people, meeting in a hut,
a classroom, a showplace and a park arbour, may provide much knowledge on
acoustics, heat stored in fuel, and optics, such as sound reflection, absorption
and echo, air convection, quantities of heat discharged by humans and the
environment temperature, sound insulation and humidity protection, diffuse
reflection, illumination, disorder motion of particles of light beams. Observe
portrait pictures, photographed at the same exposure, in a room with a white
wall and in another room decorated with dark coloured wallpaper. Then analyse
their colour and contrast. You will learn much practical physics knowledge.
Vehicles, sails and aircraft in daily life may provide not only knowledge
on kinematics and dynamics, such as velocity and acceleration of different
motion, force and reaction, but also practical experience about falling,
inertia, friction, momentum, change of atmosphere pressure and the eardrum,
even to observe motion phenomena of non-inertial systems.
2. Besides the physics principles in construction
or equipment, there is much knowledge of problems of daily life and application
of physics, e.g.
1. Sailing boats, See 11.4.11: Estimate
the load of a boat,
2. Pollution from noise, noise effects thinking and learning, white noise,
See 34.4.1: Pollution from noise,
3. Personal safety, See 4.2.5: Necessity
of seat belts in a car, problems of daily life and application of physics
3. Unlike the natural environment, the social environment
can transfer to students much useful information about physics if you remind
or encourage students to notice, to increase contact with the information
resources, and to keep alive their curiosity, desire to learn and the goal
of learning. Everything is available including effective information resources,
such as beneficial books, magazines and broadcasts, especially television
programmes distributing sciences and introducing developments in science.
As an alternative approach to physics teaching besides the school system,
you do not expect that it must provide systematic and high level of scientific
knowledge. You do not mind this very much although you can understand some
ideas better and more profoundly in school. Inspiring students' interest
in sciences is important, develop their imagination, then put forward questions.
Everything can be helpful to the growth of physics learning by students.
Of course it may not only make teaching more interesting also widen the perspective
of students if teachers can bring their attention to get information from
the resources then apply them correctly in physics teaching.
4. Environment protection is an important question
that has direct bearing on the natural and social environment. Science and
technology have successfully brought great advantages to humans but people
ignore the pollution produced by these advantages. Thus any phenomenon,
reason, prevention and cure causing physical pollution in the natural and
social environment should become a resource for physics teaching, in the
same way that all physics and its associated technology are a resource for
physics teaching. A basic principle in physics teaching is to draw attention
to physical pollution caused by lack of knowledge, e.g. the large amount
of CFCs in the ozonosphere, exhaust gases produced by cars, greenhouse effect
increasing year by year, wastewater drained off from thermoelectric power
plants and temperature increasing of water in river and lake caused by it,
and destruction of ecological balance in marine areas. These are examples
of physical pollution of the natural environment. Examples of physical pollution
of social environment that affect human health include electromagnetism
pollution produced by television transmitting towers and microwave communication,
radioactivity pollution from nuclear industry, atomic power stations and
radioactive isotopes widely used in industry and agriculture and medical
treatment, and pollution coming from airports, workshops and construction
sites. In fact the two kinds of physical pollution, of nature environment
and social, cannot be separated completely because they have direct bearing
on each other, e.g. climate change in nature and destruction of ecological
balance can directly affect human life. The increasing temperatures caused
by directional reflection from exterior glass materials of buildings, not
only influences residential life but also causes the "hot island effects"
of large architectural complexes influencing climate change in local areas.
5. Pollution from light of buildings. You should
let students understand the phenomenon and reason for physical pollution
and enhance their awareness of the need to protect the environment through
making full use of practical examples in their social environment.
1.3 The daily life of students
1. For students, first hand experiences lead to the most direct perceptions.
They can enable students to master easily physical knowledge and help them
to understand the ideas and principles of physics. The experiences of students
at first hand have been abundant, but they often overlook some daily experiences.
For example, motion always consumes energy. If you feel a glass sliding
away, you always increase force to hold it. Hot things will be cooler after
being outside for some time. What you see through a hole must be much wider
than the hole. For the same size of a thing the farther away it is the more
unclear it is. Any one of two faces of a coin may be upward after throwing
the coin upward then letting it fall. So recording these experiences in
time is not easy then apply them correctly. However, some experiences maybe
cause students to misunderstand. For instance, a bicycle will not move if
no one pedals it, so students may think that force is the reason for motion.
Also, people notice that horses pull vehicles but not reverse order and people
taking a beating always feel sorer than people beating. Such examples may
cause students to doubt whether really equal and opposite forces exist. A
grain always falls faster than a piece of paper. It may lead students to
believe that the heavier an object is, the more rapid it falls down. You
feel your hands are tired if you have walked carrying a heavy load by hand.
It may cause students to misunderstand that the hands have done work. Only
by analysing these everyday experiences can you instruct students to know
real science and its values, which is very important for physics teaching.
2. An experience you have had may convey different
kinds of physics knowledge, e.g. picking up a piece of beefsteak with a
fork. The experience may be used to learn not only about pressure but also
about levers. As pointed out above, a practical phenomenon in the natural
world often includes much different physics knowledge. The following examples
may be more complicated. An experience may convey the same kind but different
degrees of physics knowledge. For instance, a passenger will fall over when
a car increases speed or brakes suddenly. You may apply it not only to explain
inertia but also to analyse the position of the centre of gravity. You can
join broken light bulb filaments to work again. You may apply it to explain
the change of resistance and current and power and to analyse temperature
and luminosity.
1.4 Physics experiments
1. Undoubtedly physics experiments are the most important resources of
physics teaching. Replacing the experiments prepared meticulously by teachers
by the experiments that students do in nature and at home is impossible in
teaching efficiency and training of students' experiment skill and accurate
measurement. Scientific conclusions of physics experiments entirely depend
on accurate completion of physics experiments. Students' understanding of
many scientific methods also entirely depends on physics experiments, such
as how to solve the questions of not exact measurements through using significant
figures, how to deal with the questions of many factors changing simultaneously,
how to analyse expected experimental results, how to confirm an experiment's
reliability.
2. Demonstration experiments do not replace practical
experiments carried out by students themselves in a laboratory. Both types
of experiments should be well regarded in physics teaching. The more students
do themselves, the more they get from the experience. It is very different
from a classroom teaching, watching teachers' doing, listening to teachers'
explanation and following teachers' thinking. What students learn is entirely
different if they complete a well organized experiment or they do everything
themselves in an experiment, including the aim, the task, equipment. They
learn are not only knowledge and skill but also thinking and operations
of challenge and creation.
3. You should approve physics experiments completed
well with low cost instruments or daily appliances as a qualitative experiment
that do not require a high level of precision. It is not only for economic
reasons but also because the experiments may be done anywhere out of a laboratory,
at home or outside, to provide advantage for applying physics teaching resources
in nature or the social environment. However, you never do anything at the
cost of decrease of experimental accuracy. For a physics experiment, no
accuracy means no scientific status and thus no sense. For example, if the
frictional forces in the pulleys of low cost pulleys are greater than the
weights raised, this experiment is different from the simple machine studied
in physics.
4. Physics experiments can be complicated although
using few instruments or using low cost equipment. Using the body may complicate
some experiments although such experiments may refer to broad content and
give students direct experience.
1. When the inner surfaces of fingertips are pressed together both change
in shape similarly.
2. See 8.2.6: Centre of gravity of man and
woman
Centre of gravity of man and woman. It is easier for the woman to pick
up the chair because she has the lower centre of gravity.
3. If you hold the palm of your hand close to your cheek without touching,
you can feel radiant heat.
4. By narrowing your eyes and looking between your closed fingers you
may observe single slit diffraction.
1.5.0 Equipment and support systems
1.5.1.0 Equipment
1.5.1.1 Electronics
1.5.1.2 Timers
1.5.1.3 Position and Velocity Detectors
1.5.1.4 Sources of Sound
1.5.1.5 Sound Detectors
1.5.1.6 Circuits/components/instruments
1.5.1.7 Function Generators
1.5.1.8 Oscilloscopes
1.5.1.9 Advanced Instruments
1.5.1.10 Power Supplies
1.5.1.11 Light Sources
1.5.1.12 Light Paths Made Visible
1.5.1.13 Lasers
1.5.1.14 Microwave Apparatus
1.5.1.15 Computer Interface
1.5.2.0 Support Systems
1.5.2.1 Blackboard Tools
1.5.2.2 Audio
1.5.2.3 Slide Projectors
1.5.2.4 Film Projectors
1.5.2.5 Overhead Projectors
1.5.2.6 Video and Computer Projection
1.5.2.7 Photography
1.5.2.8 X y, Chart Recorders
1.5.2.9 Buildings
1.5.2.10 Museums
1.5.2.11 Resource Books
1.5.2.12 Unclassified Demonstrations
1.5.2.13 Philosophy
1.5.2.14 Films
1.5.2.15 Computer Programs
1.5.2.16 Mechanical
1.5.2.17 Motors
1.5.2.18 Pumps
1.5.2.19 Vacuum
1.5.2.20 Air Support
1.5.2.21 Ripple Tank