Introduction: Acid/Base PH Indicator Experiment (Video)

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In this project I'll show you how you can make your own PH indicator solution from Red cabbage.

If you don't prefer to read, you can skip it and watch the video instead where I have explained all the steps in detail. If you do, then continue reading the written steps along with pictures in the following steps. Find out more similar projects and gadget reviews on my YouTube channel

You must have learned in school about acids and bases (alkalis). To know if a solution is acidic or alkaline people use something know as an indicator. They come in paper form known as litmus paper or liquid solution. It changes color differently when it meets an acid or alkali.

They are sold at laboratory supply stores but today I’m gonna show you how you can make your own at home from red cabbage.

Let's get to it.

Step 1: Make the Indicator

- Grab a few big leaves of your red cabbage and stuff in into the blender.

- Add about 2-3 glasses of luke warm water and blend until you have some dark purple cabbage juice.

- Drain in through a tea strainer and then through a cloth to get rid of any veggie residue.

- Believe it or not, our PH indicator is ready.

Let's move to the next step to test it.

Step 2: Testing Time!

I gathered seven commonly available solutions which we are going to test.

1. Lemon juice

2. Vinegar

3. Carbonated lemon soda

4. Water

5. Toothpaste and water solution

6. Baking soda and water solution

7. Bleach.

- The lemon juice being the most acidic of the lot changes to a bright red color.

- The vinegar changes to a pink or less bright red color.

- The lemon soda changes to pink shade.

- The water being neutral retains the purple color.

- The toothpaste and water solution changes to a blue shade which means now we have stepped over to the alkaline zone.

- The baking soda and water solution turns a bluish-green solution.

- And finally, the bleach being the strongest base of the lot dissolves the dark purple solution and retains its own light yellow color.

You can see how the indicator solution has changed color in all the different solutions.

There's another side experiment I tried out. Next step please.

Step 3: Acid Vs Alkali

- I was told in school that acids neutralizes alkalis and vice versa so that means if I mix the solutions at the extreme ends together they should cancel each out and I should end up with a purple color.

- When I mix the lemon juice with the bleach, there is no effect the bleach is a much stronger base than the lemon juice is an acid, it will require a lot more juice to neutralize this base.

- When I mix the vinegar and the baking soda, there is a sudden release of carbon dioxide and the mixture turns a dark pink, It is still not completely neutralized so it is holding on to the pink color.

- Finally when I mix the lemon soda and toothpaste solution, both being a weak acid and a weak base neutralize each other completely and we get a perfect purple color. Same as the water solution.

This is a very fun and easy experiment you can try at home for almost free and it is also an excellent way to demonstrate the concept of acids and bases to kids.

You can also try it out with other solutions to see what you get. And do let everybody know in the comments below.

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