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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 including: 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 in the ocean or a lake? That force you are feeling is from the energy that a wave carries.How about when you go camping and stand by the fire?  The warmth you feel comes from infrared heat waves. However, we don’t always sense the presence of a wave. The last time you went to the dentist, could you actually feel the x-rays enter your body?

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
 
Safety concerns: Be sure to keep all eye, and chemical safety rules. As with all science lab activities, the most important safety rule is to follow all teacher directions.
 

Procedure

  1. Fill the bucket half full of water.
  2. Use a meter stick to measure the height above the bucket that you will drop the pebble from.
  3. Drop the pebble into the water.
    • Have one person time how long it takes from the time the pebble touches the water until the waves reach the outside edge of the bucket.
  4. Use the meter stick to measure a different height above the bucket.
  5. Drop the pebble into the water.
    • Again, time how many seconds elapse from when the pebble touches the water until the waves it creates reach to the outside of the bucket.
  6. Repeat the trial dropping from a different distance above the water.
 

Analysis:

  1. 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?
  2. How were the heights related to the energy given to the pebble?
  3. If you dropped the pebble from too high, what other actions did the energy cause?
  4. In a paragraph, describe the spread of energy from its source.

Review Science safetey rules here.

Get the plug-ins: Get Adobe Acrobat Reader , and Get Quicktime Player. (The QuickTime plug-in is needed to play sounds and movies correctly.)

Want to share photos of you or your friends doing this activity? Send it in an e-mail with the following information:

  1. The title of the activity
  2. The URL (Internet address)
  3. Your name.

Remember that no pictures can be used that show student faces or student names on it. 

Teachers should view the Teacher Site Map to relate Sci-ber text and the USOE 8th grade science core.


Updated October 24, 2008 by: Glen Westbroek

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