Given what you learned from Wolke, answer the following problem.

You're standing in a small boat which is floating in a small swimming pool. You're holding a regulation sized bowling ball. It's a the 16 lb. variety. Needless to say, it will not float. It also has no holes drilled for your finger-poos yet, either.

You drop the bowling ball into the swimming pool. It sinks to the bottom where it is completely submerged.

Does the level of the water in the swimming pool ...

1. go up a small amount?
2. go down a small amount?
3. stay exactly the same?

Ok: Boat + ball + me (the boat system) are in balance, displacing the boat-system's mass in water.

I drop the ball over the side. The boat-system goes up to displace the boat-system's new smaller mass, causing the level of the pool to lower.

The ball hits the water and submerges, causing the water level to rise, but since the mass of the ball is significantly more than that of the water it displaces (it DOES sink, after all), the amount that the water goes up is LESS than the amount it went down when the ball left the boat.

So: Boat rides higher, but the water level in the pool is lower.

I took this out of the realm of a gedenkenexperiment to the realm of empirical testing!

For a swimming pool, I used my kitchen sink. For a boat, I used a Tupperware plastic container, and for a bowling ball, I used a jar of Stonewall Kitchen's Roasted Garlic and Onion Jam.

The choices were made more along the lines of what was available rather than exact compliance, but the essential nature of the experiment stayed in tact: Float a boat, bail a ball, look at levels.

I ran some water into the plugged-up sink, then floated the jam-jar in the Tupperware, then ran a bit more water into the sink in order to 1) allow enough water to completely submerge the jam-jar and 2) have a reference mark on the side of the sink (thanks to a former occupant who tried to clean out the drains with muratic acid and instead dissolved the surface of the enamel, leaving a permanent brown-gray mark).

The boat-system (or, in this case, the Tupperware-jam-system) was pretty unstable and tended to flop over, filling with water and sinking. As I made attempt after attempt to precariously balance the jam-jar inside the Tupperware bowl as it floated in the water, I noticed that the jam jar became less and less heavy, and my fingers and moustache became more and more sticky!

Furthermore, the sweet aroma of onions and roasted garlic filled the kitchen.

On (about) my 30th try, I got everything set up right, and set my mark. I then took the jam-jar from the Tupperware and put it in the water, only to find that, now, for some reason, the jar would no longer sink below the water line!!

I replaced the jam jar with a similar-sized jar of Hot Pepper Jelly and, after some rebalancing, was able to set the mark, remove the jar and then submerge it.

It went exactly as I thought it would. Removing the jar made the waterline go down in the sink, then submerging the jar in the water sent the waterline back up, but not as far as it had gone down.

The reason for this is that, while in the 'boat', the 'bowling ball' displaces it's mass in water, but when submerged, it displaces its mass in bowling ball, which HAS to he more dense than water (because it sinks, you see) and so takes up less volume.

Still and all: I'm more interested in the gradual evaporation of the Roasted Garlic and Onion Jam over the course of the experiment!

The rate of evaporation seemed to me directly proportional to the degree of difficulty I was having balancing the jar inside the floating Tupperware, and the length of time since the stove had last been hot! Now, why these two seemingly disassociated phenomena should affect the rate of jam evaporation is quite beyond me, as is the reason for the jam seemingly condensing on my fingertips and moustache!

I think I will have to reproduce the experiment several times to gather enough statistical data to formulate a theory. I'm glad that Stonewall Kitchens has a large selection of sweet and savory jams and marmalades, so that I can avoid spot measurements and get a nice, wide sampling.

More on floating Tupperware and its effect on jam evaporation and re-condensation soon!

Last Edited: 08/27/2010