Floats or sinks

Inspired by the science fair, we decided to run a number of experiments at home this weekend. MY favorite one was "floats or sinks". We got a bucket of water and tried a variety of different items to determine whether they float or not. This was a more systematic extension of our earlier experiments with Little People. First, we ran some replications of our earlier work. Little People do indeed float. We tried a number of other plastic people related to Little People and found that these floated as well. We then tried several other items. Here is the list:

Item: Result
Rubber bands: sink
Koosh balls: sink

which led us to conjecture that rubber items sink. But this is wrong since

Rubber balls: float

Candles: float

which led Mommy to conjecture that wax things float. But this too is wrong since

Crayons: sink

We also thought that plastic floats from our earlier Little People trials. We got some confirmation of this:

Plastic spoons: float

But this "plastic hypothesis" is wrong too since

Tony Hawk: sinks

We thought that heavy things sink and by and large this is true since

Rocks: sink
Golf balls: sink
Metal spoons: sink

Bottom line: The properties of objects that lead to floating or sinking are quite complex. More study is required.

In other experiments, we tested whether big balls or small balls fall faster. We seemed to determine from dropping them at equal heights and then checking which hit the ground first that they fall at about the same rate. Feathers, however, fall more slowly than balls of any size.

I like experiments quite a lot.