Many people find it very peaceful just to sit on a beach, watching the waves roll in. After doing this activity, you'll be able to watch the waves anywhere you happen to be!

1. Get Ready    

Clear, plastic soda bottle with a screw-on top
Clear mineral oil (available at a pharmacy) or very pale vegetable cooking oil
Blue food coloring
Access to water

2. Do and Wonder

Carefully remove any labels on your bottle. First soak the bottle in warm, soapy water to loosen the glue under the labels.

Fill the bottle one-fourth full of water. Add two or three drops of food coloring, and shake it well. Then add enough oil to the bottle so it's about half full of liquid.

Put the top back on the bottle, and tightly screw it on.

Lay the bottle on its side. Wait a few minutes for any oil and water that have mixed together to separate. What do you observe?

Now tilt the bottle up and down until waves of oil roll across the liquid. What do you observe?

Try tapping one end of the bottle. What do you observe?

See if you can make small waves that move along and eventually get so high that they break (fall over).

3. Think and Write

Write a paragraph that answers these questions: Where does the energy come from that moves waves across a lake or ocean? Where does the energy come from that moves the waves in your bottle?


The waves on an ocean or lake are usually caused by wind. Sometimes, however, waves are caused by earthquakes on the ocean bottom. These waves can become so large and move so fast across the surface of the ocean that they cause major damage to the cities along the coasts. These big waves are called tidal waves or tsunamis (tsoo-nam-eees).