Colour changing water

This morning we did an experiment with red cabbage. We had some red cabbage water (which was purple) and we wanted to find out what happened when we added different things to it. We made predictions about what might happen then tested it out to see if we were right. First we added lemon juice. We guessed the lemon juice might make it go yellow "because lemon juice is yellow" so we were very surprised when it turned red!

Next we added egg white. Some people thought it might turn the water white "because it's white" but Olivia suggested it would turn the water red "the same as the other one." But when we added the egg white, it turned blue!

Then we added vinegar. Some of us thought it might turn the water white, but Harry said that because the egg white was white and had turned the cabbage water blue, the vinegar would too. But when we added the vinegar, the water turned pink!

Finally we looked at bicarbonate of soda. It was a very white powder, which Fallon said looked like snow. Most people thought it would turn the water white because it was such a bright white. But when we added it to the water, it turned blue!

We talked about our results and what we had found out - what happens to red cabbage water when you add things to it? The colour changes! The tricky science behind this is that our red cabbage water showed us whether something was an acid or an alkali - acids will turn the water red or pink and alkalis will turn it blue.

During child initiated time some of us chose to experiment with the rest of the cabbage water and try other things from around the classroom to see whether they made the water red or blue. We made predictions and then tested to see if we were right! We tried...

soap

milk 

orange juice 

water 

tea 

strawberry milkshake powder 

and honey 

Here are all the lovely colours we made!