Buoyancy Equation

Sathya and I both learned about buoyancy, and with a little help from his rocket scientist dad, we did an experiment based on the following principle:

We did not discuss water displacement, which is interesting, but I thought that might be a little too advanced for Sathya (though I got to hear a mini-lecture about it from Alex, haha).  But we did construct two boats out of Play doh: one Sathya made, and one that I made.  The key was to make the boat flat on the bottom, not too heavy, and with enough surface area so that the water could hold it afloat.

Sathya made his round with a passenger; I made mine with raft-like constructs on the bottom.  We left ours overnight to dry.  Unfortunately, Sathya's did not float.  Mine floated until water seeped into it (faulty construction), and then the weight of the water pushed it down:

Next time Sathya said he would make a more "buoyant boat."  It's neat how interested Sathya is in science now, and how fun it can be when you're little and it can still be applied and tested and still make sense!  

Speaking of which, a funny anecdote: the other day Sathya was complaining about why he was not hungry, and he said it was because the cupcake he'd eaten had only made its way to the bottom of his large intestine.  The kid's learning, at least.