• Question: why is fire hot?

    Asked by magnet360 to Ed, Sam, Steve on 23 Jun 2011.
    • Photo: Ed Morrison

      Ed Morrison answered on 23 Jun 2011:

      When you burn something, you release some of the energy stored in its chemical bonds. This energy is converted into heat and light. This is why fire is bright and hot.

    • Photo: Steven Daly

      Steven Daly answered on 23 Jun 2011:

      What Ed said. There are two different things that cause heat. One of them is infrared (IR) radiation, like for example a patio heater. This excites the molecules in your body to vibrate around very fast, and we feel this as being hot.

      The other is to do with the average speed of molecules in the air, such as the heat we feel from a radiator. This is caused by molecules in the air moving very fast and hitting molecules in our body, transfering some of their energy, and again making the molecules in our body vibrate.

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