Growing With Science Blog

Have you ever thought about sea slugs and why they are different colors? It turns out color can be pretty important in sea slugs.

One sea slug, (Elysia chlorotica), is green. Recently scientists investigated the color and found out that the sea slug makes its own food with chlorophyll! Chlorophyll, as you probably know, is the pigment plants use to make their food via photosynthesis. This sea slug not only borrows chloroplasts from the algae it eats, but also can make its own chlorophyll. It is the first animal to be shown to have that ability. Cool! ( Wired Science has a copy of the original article from ScienceNews. Both sites have ads, but the Wired site is less busy.)

Here’s a video that shows the sea slug eating algae. (The video is silent.)

This video from National Geographic shows other, more colorful sea slugs (nudibranchs). (You’ll have to close a pop-up ad.)

Why are these sea slugs so bright? The colors are to warn predators that they aren’t good to eat.

Activities:

1. Draw and color your own sea slug.View images of sea slugs by searching images online, or look for photos in books to help you. Research a particular sea slug. Find out where it lives, what its habitat is like and what it eats.

Tidepool Coloring Book has a drawing of a nudibranch you could use, as well as images of other tidepool creatures.

2. Writing Prompt:

Imagine what our world would be like if more animals could make their own food from sunlight. Imagine green cows or elephants. Now, write a story about it.

Related Activities:
Fieldwork has extensive lesson plans for a high school level marine biology/oceanography class. For example, here’s the lesson on Mollusca/beaches. The author recommends that you have access to a body of salt water to be able to do the hands on activities. Check out the “busy fieldworkers.” Now, that’s my idea of learning.

Tide Pool Invertebrates post from last summer

Thanks to Carl for the heads up about the green sea slug and Susan for leading me to the Fieldwork site.

Are you interested in floating and sinking, oceanography and/or beach science? This week we found a fascinating book at the library about a scientist who studies ocean currents by looking at trash that comes up on the beach. Let’s find out more about his research and then perform some experiments based on his findings.

Tracking Trash: Flotsam, Jetsam, and the Science of Ocean Motion (Scientists in the Field Series) by Loree Griffin Burns is about Dr. Curt Ebbesmeyer, an oceanographer who studies the huge streams of water flowing through the ocean, called currents. In 1990 his mother pointed out an article in the newspaper about piles of sneakers washing up on the shores near Seattle, Washington. Dr. Ebbesmeyer turned his scientific curiosity to the problem, and discovered the shoes came from containers that had fallen off a ship during a storm months before. The sneakers floated in the ocean currents and ended up washing up on shore. By tracking how fast and how far the sneakers moved, he and other scientists could map the direction and speed of the ocean currents carrying the sneakers.

Activities:

(Note: always watch children around water).

1. Bathtub or pool currents

Try to create a current in a bathtub or pool using a hose or a handheld shower head. Partially fill the pool or tub with water, then create a fast current by shooting water through it. Try adding a plastic floating toy to track the movement of the water flow.

2. Floating high versus low

Dr. Ebbesmeyer also studied the movement of some floating bathtub toys that had fallen off another boat. He found that the bathtub toys moved to shore more quickly than the movement of currents would have predicted. Then he floated a sneaker and a bathtub toy in seawater. What he saw suggested the answer.

Do you have an old sneaker or similar object that you could use to test this question? Float an old sneaker and a plastic bathtub toy in a tub or pool. Do they look the same in the water? Do they move through the water the same when pushed by currents?

Dr. Ebbesmeyer used seawater for his experiment. How do you think that might change the results?

His idea was that the bathtub toys floated high up out of the water and thus caught the winds. When the wind helps move an object along, it is called the object’s “windage.”

It turns out the plastic tub toys had been packaged in sets of four, yet none of the packages were washed up on shore. He wondered how the packages might influence the movement of the toys, so he placed packages of toys in tubs filled with seawater. He found the packages fell apart overnight, and so the toys were moving freely very quickly.

What else might change how an object moves in the water?

3. Plastic brick floating

In February of 1997 a ship lost containers filled with over four million LEGO pieces into the Atlantic Ocean.

Gather:

• Plastic bricks
• container for holding water, sink or bathtub

Now you are ready to answer some questions.

Do plastic bricks float?
Can you build a boat out of them?
Do you think they would float differently in seawater?

Check out the Techbrick Site for some photos of a LEGO boat race to give you ideas.

Tracking Trash: Flotsam, Jetsam, and the Science of Ocean Motion (Scientists in the Field Series) by Loree Griffin Burns

I admit, I wanted to be an oceanographer when I was in fourth grade. Now through this awesome book I can catch a glimpse of the world of oceanography.

For your information, the last two chapters are more about the trash found in the oceans, the giant pool of trash that is circulating in the Pacific Ocean, and how damaging adrift fishing nets can be. The information would be a tie-in to a study unit on environmental issues, as well.

If you liked the beach science activities from this summer, you might also be interested in learning more about dolphins.

Winter’s Tail is a new children’s book coming out in October. It is the heartrending story of a young dolphin named Winter who lost her tail after becoming entangled in a crab trap line.  After she healed, she was fitted with a prosthetic tail.

Scholastic and Turtle Pond Interactive have put together some activities to coincide with the book’s debut. You can see a short video introduction (Note: the video shows a mauled tail ), and find teaching materials at http://www.scholastic.com/winterstail/.

One of the events will be a webcast of a virtual field trip to the Clearwater Marine Aquarium in Clearwater Florida on Wednesday, October 7, from 1:00 p.m. to 1:45 p.m. (Eastern Standard Time).

Check out the science activities included in the educational materials.
There’s also an excerpt of the Winter’s Tail book.

Winter’s Tail: How One Little Dolphin Learned To Swim Again
by Juliana Hatkoff, Isabella Hatkoff and Craig Hatkoff