A very interesting simple fun toy. When the lower portion of the glass sculpture is held, the liquid rushes into the upper section, and appears to boil furiously. Then hold the top section and liquid returns to the bottom. A fantastic novelty to add to an gift range intended for adults, this product has an attractive 'mad scientist' aspect to its appeal.

The hand boiler works on the result of Charles' law by Jacques Charles. It was discovered in 1787 that the volume of gas is proportional to its absolute temperature. Inside the glass hand boiler the volume of the gas increases as the gas volume increases. This mean the heat from your hand causes the gas inside the glass to expand enough to displace the liquid.

• Runs from the heat of your hand
• Demonstrates thermodynamics
• Scientific curiosity
• Also known as a 'love meter'
• Hand Blown glass
• 4 designs/colours: purple, green, red and blue
• 18cm tall