Hand Boiler 7" – Zibbers

A twisted blown-glass sculpture that doubles as a science demonstration. Wrap your hand around the bottom bulb: the warmth of your palm heats the gas trapped inside, the pressure rises and pushes the coloured liquid up through the spiral, where it seems to "boil" in the top bulb. Let go and the liquid slowly flows back down within a few minutes.

A fascinating desk object to explore heat transfer, gas expansion and vapour pressure — and a great conversation starter.

• Height: approx. 7 in (18 cm)
• Blown glass, sealed, with coloured liquid
• Works with the heat of your hand only
• Colours vary; sold individually

Caution: fragile glass object. Do not heat with any source other than your hand. Adult supervision recommended for children.