Welcome to Day 2 of Beach Week here at The Homeschool Scientist. All week long, we’ll feature ocean and beach science fun. Yesterday, we had a fun science experiment about how waves affect beaches. Today, we are learning about really cool sea creatures – sand dollars.
During our week at the beach in Alabama, we did a lot of looking for shells. Tropical Storm Debbie just off shore in the gulf brought in huge waves and lots of shells, seaweed and other interesting things. However,the power of those huge waves crushed many of the shells into pieces so we didn’t find a lot of whole large shells. Among the broken shells on the shore, we,also, found many pieces of sand dollar skeletons.
We never did find a whole sand dollar skeleton, but on the last day my daughter found a live sand dollar while searching the sand in the ocean bottom. She was digging around the sand in about 3 feet of water and came up with this.
We could see and feel the spines moving as we held it in our hands. These spines help the sand dollar move and bury itself in the sand. Unlike the smooth sand dollar skeletons, the live sand dollar looked kind of fuzzy.
Sand Dollar Anatomy
Sand dollars are Echinoderms, as are starfish and sea urchins. Like other members of this group, sand dollars have 5 fold symmetry. You can easily see this in their 5 rows of pores shaped like petals in the top of their body. Tube feet line these pores to perform gas exchange (to breathe).
The mouth of the sand dollar is located in the middle of its underside. Tiny particles of food from the water or sand gets trapped in the spines of the sand dollar and then moved toward the mouth by small hairs called cilia. To learn more about the structure of a sand dollar, check out this sand dollar anatomy printout at Enchanted Learning.
More Sand Dollar Resources
- Sand Dollar coloring page
Cool Ocean Study Resource
Young oceanographers will want to check out R.O.V.-R Explorer. Join R.O.V.-R and his friend Dave as they explore the ocean and uncover some of its secrets. You can also check out the other great resources from Tangerine Sky Productions. They have educational videos and printables to go along. Don’t see exactly what you need? Contact them and they can customize something just for you!
Don’t miss tomorrow’s edition of Beach Week. More fun in the sun with a fab guest post!