How Do Fish (and People) Float? A Scientific Yet Practical Lesson in Swimming

How do fish float? Here are some of our preliminary ideas:

I think:

• it's because of the oxygen in their body and their light bone mass
• the gills help them move because the gills give them energy
• the water keeps them up
• they float with their flippers
• its their flippers. We float because we have two arms
• because of their flippers
• the fins and tail move side to side

I wonder: 

As we take our annual swim lessons, we get to experiment with floating and with using our "fins, flippers and tails."

Our boards help us float

Breathing and filling up our lungs

I can float on my back!

Adding some "tail and fin" action

Put it all together and we're fish, floating and swimming!

And we're happy fishies!!

I wonder:

Back in our classroom, we predict what will float and what will sink. We begin to use the scientific term buoyancy. After all, we are scientists!

We get some water and start experimenting.
Rocks, shells, buttons (with holes,) and other things "full of stuff" are not buoyant.

Feathers, straws (that are empty,) clothespins, corks, 

and other things that are flat and "not full of stuff" are buoyant!

We try making a ship that will hold a large load much like the container ships we see out in Puget Sound.
How many pennies will it hold?

 What if I turn up the sides?

My ship needs a gang plank so the sailors can get to shore easily.

I know! Popsicle sticks float! Let's add a bunch of popsicle sticks. 

A true Seabury Kid--I think, I wonder, I'll try, I discover

The Seabury Navigators, in true scientific process form, discovered several principles of buoyancy:

What makes something float in water? Anything lighter than water. 

Things "full of stuff" have more mass and aren't buoyant.

A fish has an air filled space in its body called a fish bladder that can fill up or lessen depending on whether the fish needs to go up or down in the water. 

Archimedes' principle: the buoyant force on an object is equal to the weight of the fluid displaced by the object.

As long as the water our bodies displace weighs more than we do, we float. We weigh less than the water we're in because our lungs are full of air. We float like a balloon!