Exothermic Reactions

An exothermic reaction is any reaction that gives off energy – typically in the form of heat. The two reactions we examined today utilise the reactive properties of metal powders. In chemicals energy is stored in the bonds between atoms, when we re-arrange these bonds sometimes that energy can be released.

This week we showed how common rust (Iron Oxide) can react with Aluminum. When this reaction occurs the Oxygen atoms that were joined to the Iron, switch and join onto the Aluminum instead. As this reaction occurs a lot of heat energy is released, enough to melt the Iron. You can see clearly in this thermite reaction the molten Iron forming and the solid Aluminum oxide (rusted Aluminum) forming as a white powder. After allowing the Iron to cool and solidify we collected the solid remains, interestingly some of the Iron was very colourful and some took on a crystalline form – I wonder why that might be?

Here’s what we did:

Cold Explosions

An explosive is any material that contains a large amount of stored energy that can be released rapidly. This energy is stored as potential energy and when released transforms into a combination of heat, light, sound and kinetic energy.

This week in our first science club meeting we examined simple pressure explosives. When matter transforms into a gas the particles are trying to push away from each other, if you constrain these particles inside a container the pressure builds up. Increasing pressure is used to inflate tyres, balloons and to push water through pipes. If the pressure in a container is increased too much and the container breaks, just like popping a balloon, you can make a pressure explosion.

Here’s what we did: