Density, Buoyancy and Fish
Density is the amount of matter in a given space. Not only do liquids usually have more density than gases, (and solids have more density than liquids) but different kinds of liquids have different densities.
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We have had fun with density towers before (different densities of sugar water), but this time we used different substances to make the tower.
I gathered together several liquids...maple syrup, rubbing alcohol, dishwashing liquid (purple colored), water dyed blue and vegetable oil.
I had them taking turns picking a liquid to put in the tower. They were to try to pick them in order from the most dense to the least dense. We carefully poured them down the inside side a tall glass
I was a bit surprised and happy that they chose the correct order! It is a little hard to see all the layers, but they are there!
You can also add small pieces of objects that will settle on the different layers. Try foil pressed into a small ball, a bit of rubber, a piece of wood, a small piece of plastic lead such as a fishing sinker and a raisin.
Buoyancy is how capable an object is of floating. We played with an empty plastic bottle and a large bowl of water. We filled the bottle with water and it sank to the bottom.
Then we poured most the water out of the bottle...
and it began to float.
We experimented with different amounts water in the bottle...
to get different levels of buoyancy.
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| Student's sketch |
We talked about how fish have a swim bladder that they use to take in varying amounts of air to change how high or low they float in the water.
sources:
- Considering God's Creation
- Exploring Creation with Zoology, Jeannie Fulbright
inspirations:
- Here is another one you might like to do:
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