Shows a white bucket on a scale on a lab bench. In the bucket is a chunk of ice, with a fish-shaped weight on top. Yes! It is a fishing lure! The ice and lure sit in a bath of parafin. Because the ice is less dense than the parafin it does not exert pressure on the scale, so it is weighed down by the lure. We know the density and mass of the lure, so we can work out the density of the ice using a two-part composite density equation. Most of the time, sea ice is more dense than parafin - and sinks, exerting pressure on the scale - so this detail is not needed.