How can you test if something is an acid or a base at home?

In one line

The rule

Acids turn certain indicators one colour, and bases turn them another colour.

Let's understand it simply

Imagine you are in your kitchen. You have lemon juice, soap water, and turmeric powder. Acids (like lemon juice) and bases (like soap water) look similar, but they behave differently. To tell them apart, we use something called an indicator (a substance that changes colour in acids or bases). Some indicators are already in your kitchen!

How it works

1. Take a small amount of the substance you want to test (like lemon juice or soap water).
2. Add a bit of turmeric powder to a few drops of water to make a paste.
3. Put a drop of the substance on the turmeric paste.
4. If the paste turns red or deep orange, it is a base. If it stays yellow, it is an acid or neutral.
5. You can also use red cabbage water: boil some red cabbage leaves in water, cool it, and use the purple water as an indicator. Acids turn it pink/red, bases turn it green/blue.

The story behind it

Long before modern science, people noticed that some plant juices changed colour with different foods. For example, turmeric has been used in India for centuries, not just for cooking but also for testing if something is basic. Scientists later found out why: these plants have chemicals that react with acids and bases.

Where you see it in real life

• Turmeric stains on clothes: If you spill soap on a turmeric stain, it turns red. Soap is a base.
• Lemon juice on turmeric: No colour change. Lemon is acidic.
• Red cabbage water: Add vinegar (acid) — it turns pink; add baking soda (base) — it turns green.
• Litmus paper (if you have it): Blue litmus turns red in acid, red litmus turns blue in base.
• China rose (hibiscus) petals: Boil petals in water to make an indicator. Acids turn it dark pink, bases turn it green.

Why it matters

• Helps you check if food or water is safe (too acidic or basic can be harmful).
• Used in making pickles, cleaning, and even in medicine.
• Foundation for chemistry experiments in school and exams.
• Important for understanding how our body and many products work.

Common mistakes

• Thinking all yellow things are indicators — only some, like turmeric, work.
• Using too much or too little of the indicator — always use a small, visible amount.
• Not knowing that some substances are neutral (like pure water) and may not change colour.

Remember it

Turmeric turns red with base, stays yellow with acid — just like soap on a turmeric stain!