ShareForce, Energy, & Motion - Spreading Energy
Waves are fun, waves are full of energy, waves are far out, and waves are near by. Waves are all around us; we come into contact with many different kinds of waves on a daily basis. A wave is generally described as "a disturbance in matter or space that transfers energy from one place to another." Cool!
Waves
carry energy, and waves can go through many things like glass, walls,
air, water and even empty space. There are many kinds of waves, light
waves, sound waves, water waves, etc., but all waves have the same basic
characteristics; cycles, amplitude, frequency, and wavelength.
Some examples of waves are sound waves, radios waves, microwaves, visible
light waves, earthquake waves, cell phone waves and water waves.
Some waves are invisible and cannot be seen, other waves can be seen by the naked eye. Which waves in the animations above can actually
be seen and which waves cannot? What are some other modern technologies
that use waves? What kinds of waves are they?
Have
you ever felt the force of a wave when you were at the ocean or lake?
That force is from the energy that a wave carries - the force caused
by the energy in the wave. Remember, a wave transfers energy
through matter or space, and energy is needed to create a force (a push
or a pull).
Whatever a wave goes through is called a "medium" so if a wave moves through water then water is the medium for that wave. If a wave goes through air then air becomes a medium for that wave. Some waves have many mediums. Light, for example, can travel through air, water, glass, and even empty space (and other things as well). These would all be mediums for light, but sound waves cannot travel through empty space, so space would not be a medium for sound.
Materials:
- Bucket
- Water
- Meter stick
- Small pebble
- Two people
- Watch, clock, or stopwatch
Procedure:
- Fill the bucket half full of water.
- Use the meter stick to measure the height above the bucket from which you will drop the pebble.
- Drop the pebble into the water.
- Have one person time how many seconds elapse from when the pebble touches the water until the waves it creates reach the outside edge of the bucket.
- Use the meter stick to measure a different height above the bucket.
- Drop the pebble into the water.
- Again time how may seconds elapse from when the pebble touches the water until the waves it creates reach the outside of the bucket.
- Repeat the trial with a different distance above the water.
Safety concerns: 
Be sure to follow all eye, and chemical safety rules that
are specified by your teacher in all general laboratory experiences.
As with all science lab activities, the most important safety rule is to follow all teacher directions.
Analysis:
- How did the length of time it took for the waves to leave the pebble and reach the side of the bucket vary between the different heights?
- How were the heights related to the energy given to the pebble.
- If you dropped the pebble from too high, what other actions did the energy cause?
