01 Jul Stem Challenge: Under the Sea
Next week’s Summer Program theme is Under the Sea! This week, we are going to deep dive into how sharks are able to move throughout the ocean! Here is a simple science lesson for our weekly #CMMSStemChallenge in buoyancy and the anatomy of the shark to explore how sharks float!
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Sharks are buoyant, in other words they don’t sink but they really should! Buoyancy is the ability to float in water or other fluids. Sharks need to put effort into remaining buoyant. In fact, if they stop swimming they will sink. So how does a shark float? There are three main ways that sharks use their bodies to float. This floating shark activity below covers one of them, the oily liver! Sharks rely on a pretty big oil-filled liver to help them stay buoyant in water. Let’s learn more about how that works below!
- Shark Challenge Worksheet
- 2 Water Bottles
- Cooking Oil
- Large Container Filled With Water
- Sharpies (optional but fun to draw shark faces)
- Plastic Shark (optional but you can find them at the dollar store)
- Fill each water bottle equally with oil and water.
- Set out a large container or bin filled with water that is big enough to hold both of the bottles and possibly a shark toy if you have one. These bottles are going to represent a shark, so get a little crafty and draw a shark face on the bottles to make them look like a shark.
- The oil bottle represents the oil that is in the shark’s liver. Using the hints on the worksheet, guess what you think will happen to each bottle as you place it in the bin of water.
- Test your hypothesis! Write what happened on your worksheet and read below why you got this result.
- You can now use this setup as sensory play! Use your imagination.
Explanation: SHARKS ARE BUOYANT!
As you can see the oil filled bottle floats! Which is exactly what the large oil-filled liver of the shark does! It’s not the only way a shark remains buoyant, but it is one of the cool ways we can demonstrate shark buoyancy. Another reason that you might have guessed is that oil is lighter than water.
There are actually two other ways a shark’s body helps with buoyancy. Another reason sharks float is because they are made of cartilage rather than bone. Cartilage is much lighter than bone. Now let’s talk about those shark fins and tail. The side fins are somewhat like wings while the tail fin generates constant movement pushing the shark forward. The fins lift the shark while the tail moves the shark through the water. However, a shark cannot swim backward!