The science of fire

May 30, 2018

Photo by Jacob Kiesow on Unsplash

It’s getting hot in here with our Fire and Light show taking over our Science Theatre this half term, and our fiery show will see our science communicators set money on fire, play with the colour of flames, and even set light to a fire tornado. Don’t worry, the Health and Safety is all in place and no one’s leaving with singed eyebrows.

As we study the fire triangle and perform exhilarating experiments this half term, we’ve decided to dig into the science of fire. More specifically, we answer one burning question- what makes fire change colour?

The colours of flames come from two things…

While colour can depend on temperature, chemical reactions often take most of the credit. A fire itself is the result of a chemical reaction known as combustion, where fuel and oxygen react with one another and atoms rearrange themselves irreversibly.

For this to occur, fuel must reach its ignition temperature, and combustion will continue if there is enough fuel, heat and oxygen.

Once the temperature gets hot enough for the chemicals in the fuel to react with oxygen, it results in a colourful reaction. Red colours are the coolest flames, while lighter colours represent scorching temperatures.

In wood fires, the colours also come from the substances burning within the flames. The fierce orange flame is due to the presence of sodium, which emits once heated, copper compounds transform into green or blue, and lithium turns into red.

Why does fire burn blue sometimes?

The colour of flames is not limited to the glows of warm reds and oranges, and most of us have probably seen a blue flame.

The colour of a flame is influenced by oxygen supply, meaning that low-oxygen fires contain uncombusted fuel particles, leading to yellow glows. High-oxygen fires burn blue, and its flames are the hottest, defeated only by the heat of a white flame.

As with other colours, blue is a direct consequence of a chemical reaction, with carbon and hydrogen producing both blue and violet flames.

If you’re coming to visit us with the little ones over half term, don’t forget to pop in to the Science Theatre! For times and to book your tickets to Fire and Light, please see here.


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  •   What is Techniquest?

    Techniquest is an educational charity, with a science centre in Cardiff Bay. Our mission is to embed science in Welsh culture through interactive engagement. We provide a range of services to schools and teachers to complement formal education provision in Wales and work extensively with public audiences.

  •   Where can I park?

    We are pleased to be able to offer all of our visitors discounted parking with Q-Park, our preferred parking partner.

    The Q-Park operates the Cardiff Bay car park in Pierhead Street which is around 8 minutes walk from Techniquest.

    We have agreed a special discount rate for our customers of 15% off all pre-bookings.
    Pre-book and guarantee your space here using the code TECHNI15.

    There are also nearby pay-and-display car parks on Stuart Street and Havannah Street. Please do not park on Havannah Street itself.

    We regret that there is no parking on-site at Techniquest.

  •   Who is it for?

    Techniquest is suitable for all ages! We do have special events for certain groups, however — see Toddler Days and Home Educator days.

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