Acids and Bases Experiment for Middle School You Can Do At Home

We completed an acids and bases experiment for middle school during one of our lessons on chemical reactions. It was one of our favorite science activities.

When you’re studying different acids, bases and the pH scale with your tweens, use this experiment to help them grasp the difference between the two, and how to use the pH scale.

You’ll use a red cabbage indicator to test the pH value of common household items. It’s a simple, yet powerful lab, that older kids love doing.

I’ve also designed a printable to help make it even easier for you to do this science experiment in your homeschool.

First, let’s review some basic concepts before you start this great experiment.

What are Acids and Bases?

Acids and bases are compounds you find everywhere, yet have very different properties.

When you put acids into water, you create a solution. During this reaction, the acid will actually release one of its protons, or Hydrogen ions (H+).

This means that the positive and negative ions are no longer balanced, causing the solution to become acidic.

Common acid traits are:

• tasting sour
• corrosive

When a base is put into water, it accepts a proton, forming a Hydroxide ion (OH-). It becomes alkaline.

Familiar traits of basic solutions are:

• slippery to the touch
• bitter-tasting

Acids and Bases Experiment for Middle School

There are a few ways to determine whether household items are acids or bases.

One way is to use litmus paper. If the item being tested is an acid, the litmus paper will turn red. If it’s a base, the paper will turn blue.

A second way to test is to use a pH test strip. Again, if the item being tested is an acid, it will register as a low pH on the strip and if it’s a base, it will register as a high pH.

You can also test for acidy through taste. Acids will have a sour taste, while alkaline substances will have a bitter or soapy taste. But only use this method if you are 100% sure that the item being tested is safe to ingest.

A fourth way to test the pH level of household items is to make an “indicator” and add the common products to it and see how the color changes.

Keep reading for step-by-step instructions on how to use this method to complete a science experiment on acids and bases at home as well as helpful printable lab worksheets for pH testing.

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pH Scale for Kids

As you can imagine, it’s important to know how acidic solutions are, so we know how to handle them. That’s where the pH scale comes in.

The scale ranges from 0 to 14 and solutions with a pH number less than seven are acidic (acids). Those with a pH number greater than seven are basic (bases/alkaline).

If a solution falls right in the middle, with a pH number of seven, it is neutral.

Household Acids and Bases

Here are some common household items that fall on either side of the pH scale as well as some that are considered neutral. *This is not a complete list.

Acidic Household Items

• Lemon juice
• Vinegar
• Soda
• Aspirin
• Sour Candy
• Tea
• Hydrogen Peroxide
• Apple Juice

Household Items that are Bases

• Baking soda
• Ammonia
• Drain cleaner
• Soap
• Shampoo
• Toothpaste
• Antacids (like Tums)

Neutral Household Items

• Milk
• Water
• Salt
• Oil

Acids and Bases Experiments

The best part of this kitchen experiment is that you don’t need a lot of fancy lab equipment to complete it. This fun activity uses things you already have on hand to test the pH level of various household substances.

Remember, even though you’re working at home, make sure your teen follows basic safety procedures.

How to test an acid and base without litmus paper?

You’ll use an indicator, or a universal indicator solution, which is a compound that changes color depending on the pH level of the solution. In this case, red cabbage.

For this acids and bases lab:

• red cabbage
• a knife and cutting board
• pot
• water
• measuring cup
• strainer
• test tubes or clear glasses
• a variety of household items to test
• eye droppers
• a copy of the printable acids & bases experiment worksheets

Glass Test Tube SetDisposable PipettesMeasuring CupFine Mesh Strainer

 

How to Make a Red Cabbage Indicator

1. Coarsely chop up about 1/4 of the red cabbage, place it in a pot, and cover it with water.
2. Cook over medium heat, for approximately 15 minutes. Just long enough for the water to absorb the purple pigment from the cabbage.
3. Strain the cabbage, putting the cabbage juice into a measuring cup.

If you don’t want to use the homemade indicator, you can always use pH paper, or litmus paper, to test for the pH levels.

But it’s way more fun to use the cabbage!

Acids and Bases Worksheet

To help your tweens complete this experiment, use these helpful acids & bases experiment worksheets.

Inside this printable lab packet you’ll find:

1. Experiment Supply List
2. Step-By-Step Instructions
3. Questions to Ask Before the Experiment
4. Acids and Bases Worksheet: a page for students to record their findings throughout the lab
5. Questions to Ask After the Experiment
6. Scientific Method Sheet

Testing Acids and Bases Experiment

For this lab, we tested over a dozen household products, but you can choose how ever many works for your family.

Here are some of the things we tried:

• Bleach
• Cola
• Milk of Magnesia
• Orange Juice
• Pickle Juice
• Salt
• Shampoo
• Tomato Sauce
• Window Cleaner

You’ll need some vinegar and laundry detergent to set the baseline for the experiment. Aside from those, pick some things from the list above or have your kids go around the house grabbing things they want to test.

Try to select things that fall into the three pH levels – acid, base, and neutral, so your kids can see the differences between them.

While cabbage is cooking, gather up your supplies and a copy of our pH testing worksheet for your tweens to record their findings.

Once you’ve strained the cabbage, you’re ready to begin.

At the beginning of the experiment, you’ll want to create a visual baseline for later comparison.

To do this, line up three test tubes or glasses. Fill an each one 1/4 full with the indicator. Then, mix in a dropper full of vinegar (a known acid), to one glass tube and watch the color turn red.

Don’t add anything to the second glass/tube because this one will stay a straight cabbage indicator. In the one, mix in a dropper full of laundry detergent (a known base) and watch the color turn green.

Set these off to the side in this order – acid, neutral, base. They’ll be the baseline to judge the other mixtures against.

Now it’s time for the testing of various substances. Kids should fill a test tube 1/4 full of cabbage indicator and add an eye dropper full of the household substance and mix well.

They should see a color change.

Compare the color to the visual baseline (the three glasses/test tubes you made up) to see where that product falls on the pH scale.

For example, let’s say you want to test the pH level of shampoo.

Remember that cabbage indicator that you put into the measuring cup? Fill an empty glass or test tube about a quarter of the way full. Then, fill an eye dropper with shampoo and add it to the tube with the liquid. Mix well.

What happened?

It should have changed color – going from the purple cabbage color toward a darker red/purple because shampoo is an acid. So it has created an acidic solution.

Look at the visual baseline you made. If the shampoo/indicator mix is darker than the indicator/ vinegar mix, then shampoo has a lower pH number than vinegar. If it’s a bit lighter, vinegar is lower.

Keep going with the rest of the items you chose (using clean glasses each time) and putting the different solutions in order based on their acid-base reaction. Go from the lowest acid to the highest base.

As you can see, it’s pretty easy to test household items for their pH level and is a great way to teach chemistry at home.

Middle School Chemistry Experiments

This is just one of the fun experiments you can do with common household products. Check these out for even more.

• Solids and liquids chemistry experiment
• Make plastic from milk
• In chemistry, build atoms with candy
• Make homemade fruit gummies to learn about polymers
• Lava lamp science project

How did your acid and base experiment turn out?