Red Turmeric
Add a big pinch of turmeric powder to a few teaspoons of water to make a turmeric solution. Add soap (Surf or Vim) to your turmeric solution. What happens? Add a drop of lemon juice to your solution now. What happens?
Explanation:
Turmeric is a pH indicator. That means it can be used to find out if something is acidic (sour) or basic (bitter). Not all things are edible. In that case we need to use indicators to find out if they are acidic or basic. The soap is basic. That’s why it turns the turmeric solution into red colour. The lemon juice is acidic. It changes the colour back to yellow. If you add more soap now then the colour will turn back to red!