Today we did a simple test to identify what substances around the kitchen are Acid or Alkaline. We used a red cabbage water indicator for this.
It is a really easy but fun experiment for little ones and they get to feel like real Scientists while they use pipettes and add drops to jars of purple chemical indicator.
You will need:
- Red Cabbage
- A pan, sieve and boiling water
- Several substances to test, for example, Tea, Coffee, Lemon juice, Vinegar, Bicarbonate of soda and Milk
While the cabbage soaked, we drew up a simple chart. I had to answer the door while they did this and the little ones got a bit confused, but the substances to test are listed down one column using word, pictures or both depending on the age of the child. Then you need a column for acid (red/orange colour change) and another for Alkaline (purple/ blue colour change).
Add an inch or so of water to the jars
Once the Red cabbage water has cooled down a bit, add about 15/ 20 drops of it to the water in the jars. This is your chemical indicator.
Then choose a substance to test and add a small amount to the water in the jar. Give the jar a swirl and see what colour it changes to.
The milk turned the water purpley colour, so it shows that it is an Alkali.
We then tried the vinegar. I asked the children if they could guess what would happen to this jar.
It turned the water a reddy pink colour! This means it is an Acid.
The children ticked the correct column on their chart to record their results.
Once we had tested everything a few times, I let the children play with the bits on the tray. They loved mixing things together. Especially when the vinegar and Bi-carb get mixed!