Today for STEM Friday we are featuring The Next Wave: The Quest to Harness the Power of the Oceans (Scientists in the Field Series). Author Elizabeth Rusch introduces us to a number of scientists who are working hard to convert the mechanical energy of ocean waves into electrical energy. See a full review at our sister blog, Wrapped in Foil.
Waves are actually very complex and we are still learning about them.
How do waves form?
The waves in the ocean form due to wind blowing on the surface. The shape and size of the waves depend on the force and steadiness of the wind, and the distance over which the wind travels, called "fetch." The shape of the wave is also influenced by the depth of the water, especially as it meets the shore.
Activity 1. Exploring Waves
- Plastic bin
- Food coloring
You may use a sink or bathtub to hold the water, but because you will be blowing across the surface, a plastic bin situated on the waterproof surface of a counter or tabletop will probably be easier to maneuver around. This would be an ideal activity to try outdoors.
Fill the bin 3/4 full of water.
Ask the children if they have ever been to the ocean and seen waves. If they have not, consider showing a video (YouTube has dozens).
Brainstorm about how to form waves. If water splashes are not a problem, allow the children to free-explore their ideas about how best to produce waves. They will probably put their hands in and swirl the water.
Now reveal that waves are formed by wind blowing over the water. Have the children blow and see how the waves look different from those they produced using their hands.
Did they form in parallel lines like in the video above?
Once the children have seen waves, add a drop of food coloring to the water and have them blow waves again. How does the water move? Do all layers move the same way?
Many texts will tell you that the water in the deeper part of the ocean does not move forward as a wave passes by, but simply travels in a circle or oscillates. Proof is given when an object floating in the water simply bobs up and down, rather than moving forward.
If you look closely at the second video, however, you will see that the top layer of the water with the food coloring moves across the surface with the waves. Why? One possible solution is that the bin is too shallow and the waves are behaving more like those at the shore, where the circular motion is disrupted. Can you think of any other reasons?
Activity 2. Water Vortices
Older students might want to try the experiments with vortices suggested in this video by Physics Girl (has a pop-up ad):
Isn't that incredible? I can't wait until it is warm enough to try it myself.
If your children like these activities with waves, be sure to pick up The Next Wave: The Quest to Harness the Power of the Oceans (Scientists in the Field Series) . It introduces young readers to an exciting new technology that will capture the energy of waves and convert it to useful electrical energy. The book will definitely inspire young readers who want explore waves and oceans. It is also a great resource for adults who want to learn more about this relatively new area of research on a potentially renewable source of energy.
Age Range: 10 - 14 years
Grade Level: 5 - 9
Series: Scientists in the Field Series
Publisher: HMH Books for Young Readers (October 14, 2014)
You might also be interested in other books we have reviewed from the Scientists in the Field series.
Disclosures: The book was provided by the publisher for review purposes. I am an affiliate for Amazon, and if you click through the linked titles or ads and make a purchase, I will receive a small commission at no extra charge to you. Proceeds will be used to maintain this self-hosted blog.
Come visit the STEM Friday blog each week to find more great Science, Technology, Engineering and Math books.