1. Line the three glasses up in a row and pour an equal amount of cold tea into each of them.
2. Add a few drops of lemon juice to the glass of tea on the far left. Watch to see what happens to the color of the tea.
3. Add several drops of the liquid dish detergent into the glass on the far right. Watch to see what happens to the color of the tea.
4. Now compare the glass of tea with lemon juice and the glass of tea with liquid dish detergent to the glass of tea in the middle. What do you see?
The tea with lemon juice added is an acid on the pH scale.
The tea in the middle with nothing added is neutral on the pH scale.
The tea with the dish detergent added is alkali on the pH scale.