Equipment:

• Bunsen Burner
• Gas Hose
• Striker
• Stand
• Wire Mesh
• Paper Cup
• Water
• Thermometer

Demo: Burn one paper cup and boil water in another. Use a small paper cup with a flat bottom (no edge ring) and fill it with water almost to the top. Place it on the wire mesh over the flame of the Bunsen burner as shown in the picture. The water in the cup will boil but the paper will not ignite.

Explanation: The water has a very high specific heat and a high molar heat of vaporization, due to hydrogen bonding. The water absorbs heat so rapidly that the cup does not get up to kindling temperature.

Note: paper is ignited at 233°C