The Hand Boiler is a glass device that demonstrates the effects of heat on gas and liquid. When held in the hand, body heat causes the liquid to move from the lower to the upper chamber, simulating a boiling effect. Features: Heat-Responsive Movement: The liquid rises through the tubes when the lower chamber is warmed by hand. Glass Construction: Made from sealed, twisted glass containing a heat-sensitive liquid. Educational Use: Helps illustrate Charless Law and vapor-liquid equilibrium. Science Demonstration: Shows the principles of heat transfer and gas expansion in an interactive way. Variety of Designs: Comes in assorted colors (blue, green, yellow, purple, red) and looped glass shapes. Color and shape are randomly selected. Package Includes: 1 x Hand Boiler