Heat sources in the science lab

Excuse me! What are you doing?? Heating this up! Just like you asked me to. Duh!

I didn't mean with a candle! That takes forever! For some chemical reactions to take place, you have to heat up the mixture. Okay, I'll show you the different ways to heat mixtures! A candle is perhaps not the best heat source!

Since it only provides a small amount of heat. The other problem with a candle is that black residue it leaves behind - soot. If you don't want any soot you can use a spirit burner, which burns flammable liquids. It produces a flame not much hotter than a candle's flame - but there's no soot left behind! It needs fuel to burn so make sure you know what kind of fuel it uses so you can refill it when it gets low!

BUT! Only refill the spirit burner when it's cooled off. Otherwise it might result in... Yes, a great ball of fire! Here's the best heat source in the laboratory...

It burns flammable gas, which is fed from a pipe on the side. It was invented in the 1850's and got its name from the German chemist Robert Bunsen - we call it the Bunsen burner. The Bunsen burner has the hottest flame. It can reach temperatures of more than one thousand degrees Celsius. What makes it really handy is that you can adjust the amount of air that flows to the flame as well as the amount of gas that it burns.

Less air if you want a cooler flame... ... or more air if you want a hotter flame. Less gas for a smaller flame... ... or more for a larger flame. But hang on!

WHY not just use a stove? In chemistry we often use small containers for heating. A lot of the heat from a stove would simply diffuse into the air. And if the stove is electrical it won't heat up as fast as a burner. You also can't change the temperature as quickly.

So which heat source should you use? Well! It all depends on the experiment! If you're uncertain, you can always ask your teacher... Careful!

Watch out! Or make sure you have a trusted expert around!