Easy Science Fair Project





Introduction: Easy Science Fair Project

About: My name is Randy and I am a Community Manager in these here parts. In a previous life I had founded and run the Instructables Design Studio (RIP) @ Autodesk's Pier 9 Technology Center. I'm also the author ...

Making a PH reactive liquid is an easy science fair project that could be made in a single evening with great results. This project requires little more than red cabbage and some basic household supplies. This project is an easy way to visually determine if a liquid or powder is an acid or a base. With the plurality of liquids and powders in your household, this allows for vast experimentation.

Step 1: Materials

There are few required materials for this project.

The first and most important item is red cabbage. One large cabbage will yeild more PH liquid than is necessary, so it is probably best to cut it in half (or get a very small cabbage).

Also, a standard coffee filter is recommended.

Step 2: Chop It Up

Chop one of the halves of the cabbage into little pieces. Put these pieces in a bowl.

Step 3: Add Boiling Water

Boil a few cups of water, and then pour it into the bowl until the cabbage is fully saturated and the water level reaches the top.

Step 4: Wait

Wait for the water to cool down to room temperature. Notice that the liquid will grow increasingly dark purple.

Step 5: Pour the Liquid

Pour the liquid into a jar or plastic container.

It is recommended to pour the liquid through a coffee filter to keep bits of cabbage out of the final liquid.

Step 6: Prepare

Pour a small amount of the liquid into a wide-mouthed secondary container.

Step 7: Experiment

You can now test where different liquids and powder to determine if they are an acid or base.

Acidic items will turn the liquid red.

Bases will turn the liquid green.

The more pronouned the color, the more further the chemical being tested is from being neutral.

Use new PH indicator liquid for every test and never mix acids and bases together because the chemical reaction they create can potentially be dangerous.

Step 8: DIY Litmus Paper

This solution can also be used to make litmus paper.

All you need is some white acid-free drawing paper.

Cut the paper into small strips and then dip the strips into the solution. They are now ready to be used to test where a chemical falls on the pH scale.

Just like in liquid form, red indicates an acid and green indicates a base. Blue is neutral.



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14 Discussions

can you use the purple liquid to dye fabric or yarn? It is a very pretty color.

3 replies

Yes, I have. I used an alum mordant on my wool first, dyed the first bathch with no additions to the solution, second batch with some acid and thrid batch with an alkai, produced a lovely range of colours.

I don't know. It would be easy enough to try and see how it goes. I would speculate it would make a much lighter purple color than it currently is.

I am picking some up next grocery day. I have a ball of cotton yarn to try it on.


1 year ago

Thank you for this i am hoping to show my science teacher this!

Can you use another thing instead red cabbage? I don't have red cabbages HELP ME!!!

Very interesting, Thanks for sharing!

You can also use purple all-the-way-through potatoes e.g. Purple Peruvians. It may help to dilute the solution with distilled water so it will change color more readily.

love your vid/gif!! :^D

Eons ago I was a science teacher and this is neat idea demonstrating that chemistry is all around us.