Density Demo taken up a notch

I was helping out with our summer church camp and it was a science theme. They have a demonstration at the end of each day. The demo today really took my old diet Coke/regular Coke demo up a couple of notches.

First, put in a regular Coke, then a diet Coke. Ask for predictions from the audience each time about what they expect will sink or float and why.

Try:
Pepsi and Diet Pepsi
A lemon and a lime (the lime sinks, the lemon floats)
An peeled orange and an unpeeled orange (the orange floats, the peeled orange sinks)
And for a big finale, two bowling balls - one 7 lb and the other 16 lb (borrowed from a bowling alley). The 7 lb bowling ball floats and the 16 lb one floats!

And it's all about density and how tightly packed together those particles are. High density items (like people packed together on a bus during rush hour) that are more dense than water will sink. Low density items (like people in a bus during a slow time) will float!