BACKGROUND:
We use energy to do work. Energy
lights our cities. Energy powers our vehicles, trains, planes and
rockets. Energy warms our homes, cooks our food, plays our music, gives
us pictures on television. Energy powers machinery in factories. Energy
is defined as "the ability to do work."
When we eat, our bodies transform the
food into energy to do work. When we run or walk, we "burn"
food energy in our bodies. When we think or read or write, we are also
doing work. Cars, planes, trolleys, boats and machinery also transform
energy into work.
The word energy is used in many
different ways. In this lab we will look at how energy can be created by
different ways.
PROCEDURE:
- Discuss the meaning of energy.
Emphasize that energy is difficult to describe but can be derived from
many things. In this lab, students look at different "energy
makers" and try to establish the type of energy they produce. This
lab looks only at light, mechanical, and sound energy. This is only an
introduction and students should not be expected to understand the
physics of the items. Have students go to the appropriate stations.
- Light energy - Light energy
is created when light is used. Solar batteries and solar heating create
energy from light. There are differences between light energy and heat
energy. Light does not always have to get hot; for instance, solar
batteries.
- Mechanical energy - Simple
machines create mechanical energy. It is energy created when it is
physically easier to move an object.
- Sound energy - There is
energy created when air molecules are disturbed. Ask students if sound
can hurt your ear drums. Yes, loud noises can rupture the drum of your
ear.
- ANSWERS:
- Flip-flop top (mechanical/moves)
- Bells (sound/different tones)
- Prism (light/breaks up)
- Hand Lens (light/concentrates)
- Peeler (mechanical/lever)
- Radiometer (light/makes energy) [The vanes, or wings in the
radiometer are alternately dark and light in color. When light strikes
these wings, heat is transferred to each one, but not to the same
degree. The light wings reflect the rays, and the dark wings absorbs
the rays. When the freely moving particles of air inside the
radiometer strike the light reflective vanes, they absorb very little
energy and do not bounce off very fast. When the atoms strike the dark
vanes, they absorb a great deal of energy and rotate at a terrific
speed.]
- Force Machine (mechanical) [Pick up one ball and let it go -
it will hit the other balls. The energy will go through the balls and
release a certain amount of energy. For every action there is a equal
and opposite reaction.]
- Puddle-jumper (mechanical/moves)
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