Pencaitland Primary Blog

We have been learning that some changes are temporary and can be easily reversed.  Last week we saw we could turn water into ice and back into water.  Today we learned that some changes are permanent and cannot be reversed.  There are three main ways of making permanent changes happen - by heating (eg boiling an egg) by mixing substances together, or by passing electricity through them.

Our first experiment involved putting electrodes from a battery into a cup of salty water.  We saw that the electricity changed part of the salty water into a gas which made bubbles.  This gas is called chlorine and it made the water smell like a swimming pool!

We then watched an experiment with a lit candle.  A reaction between vinegar and baking powder produced a gas called carbon dioxide which out out the candle.

Our final experiment also involved vinegar and baking powder. When they were mixed we could see the effects of the gas given off blowing up a balloon. Gases given off in these experiments are examples of a permanent change.

The best part of science today was watching the vinegar and baking powder fizz and putting out the candle                  Ellis

I liked seeing the balloon blow up by itself    Jack G

I liked doing the experiments with the balloon, the vinegar and the baking powder       Arran

The best part of the experiment was when the vinegar and baking powder bubbled up and blew up the balloon.                      Isla

It was very tricky trying to put the balloon on top of the bottle but it was fun           Hannah S

I liked trying to pour the baking powder into the balloon                Alasdair

I liked putting the wires into the salty water and seeing it fizz                      Eilidh S

I loved every single bit of the experiments           Harry