Float or Sink?
Ice is unusual, from a chemist's perspective, in that its solid form is less dense than its liquid form and so it "floats in itself". This behavior is contrasted with t-butanol, which "sinks in itself". In this demo, ice is put into water and observed to float. But frozen t-butanol sinks when it is placed in liquid t-butanol.
This demo can be used when states of matter or density are introduced. It can also be used as a demonstration of the strength of hydrogen bonding in water or anytime the peculiar properties of water are being discussed. Allow about 10 minutes for this demo.
Ice is unusual, from a chemist's perspective, in that its solid form is less dense than its liquid form and so it "floats in itself". This behavior is contrasted with t-butanol, which "sinks in itself". In this demo, ice is put into water and observed to float. But frozen t-butanol sinks when it is placed in liquid t-butanol.
- 2 glass cylinders
- water
- t-butanol
- ice bucket containing ice and a small plastic container of frozen t-butanol
- small ice scoop
- scoopula
- background box
Set the two cylinders in front of the background box. The black background works best. Fill one cylinder about two-thirds full of water and the other about two-thirds full of t-butanol. Add a scoop of ice to the cylinder containing water and add the frozen t-butanol to the cylinder containing t-butanol. The ice should float and the solid t-butanol should sink.
Wear goggles. t-Butanol can be an irritant to the skin and eyes. Vapor can irritate the upper respiratory tract, but this is rarely a problem due to its low volatility. t-Butanol is flammable, however, so do not perform this demo near a source of open flame and have a fire extinguisher at hand.
