An acid is a substance that reacts with a base. They are usually identified as a sour tasting chemical. Common acids found in the kitchen are lemons, apple juice, orange juice, vinegar and black coffee. A base is a substance that will neutralize an acid. Common bases found in a kitchen are baking soda and egg whites.
In the Science experiments below kids with work with Acids and Bases.
We will be following the scientific method to complete these experiments
- Ask a question
- Formulate a hypothesis (what do you think will happen)
- Conduct the experiment
- Collect data, Record your results
- Analyze the date and make a conclusion
Experiment 1 Red Cabbage and Vinegar
In this experiment you will use the juice from a can of red cabbage to determine if vinegar and baking soda are acids or bases. The juice from the can of red cabbage is a natural PH indicator and will change color according to acidy levels.
Cabbage contains a pigment molecule called anthocyanin also called flavin. When acid is added to it it turns a red color when a base is added it will turn a green color. Neutral substances will make it turn purple.
How can you tell if something is an acid or a base? The PH scale the scale that determines is something is an acid or a base. Substances with a PH of 0-6 are considered acidic and substances of 8-14 are considered alkaline or basic (bases). 7 is neutral.
How do you think you can tell the difference between an acid and a base? Do you think an acid acts differently from a base? Let’s conduct this experiment to find out.
- can of red cabbage
- 3 glass jars (we used mason jars)
- 1 tablespoon of vinegar
- 1 tablespoon of baking soda
- 1 tablespoon of distilled water
- can opener
Step 1: Open the can of red cabbage, using the strainer/colander drain the cabbage juice over the bowl.
Step 2: Put 2 tablespoons of red cabbage juice into each of the three glass jars.
Step 3: Add 1 tablespoon of vinegar to the first jar, add 1 tablespoon of baking soda to the second jar and add 1 tablespoon of distilled water to the third jar.
Step 4: Watch what happens and record your results. What color did the liquids in the jar turn?
Research and Conclusion
The red cabbage juice is a natural PH chemical indicator. A chemical indicator is a substance that turns color when other substances are present.
Substances with PH levels above
In the first jar you added vinegar which is an acid. You should have noticed that the color of the cabbage juice changed. The red cabbage juice turned redder. The stronger the acid, the stronger color the chemical indicator (red cabbage juice) will turn.
The baking soda (base) was added to the second jar. You will notice that the chemical indicator (red cabbage juice) turned green.
In the third jar you added distilled water. The distilled water is a neutral property. You will notice the the chemical indicator (red cabbage juice) did not change or looked purple.
In conclusion, we found that the vinegar was an acid and the basking soda was a base, the distilled water was neutral.
Experiment 2 Vinegar and Orange Juice
In this experiment you will find out what happens when you mix and acid with a base. You will be using vinegar and orange juices as acids and baking soda as a base.
What kind of chemical reaction takes place when you mix and acid with a base?
What do you think will happen when you mix and acid (vinegar or orange juice) with a base (baking soda).
- 1 cup water,
- 1/2 cup vinegar
- 1 cup orange juice
- 3 teaspoons baking soda
- 3 cereal bowls
Step 1: Pour the water in the first bowl, vinegar in the second bowl and orange juice in the third bowl.
Step 2: Pour 1 teaspoon of baking soda into each of the bowls and mix each one with a separate spoon.
Step 3: Watch what happens and record your results.
Research and Conclusion
What happened when you added the basking soda (base) to each of the bowls?
The bowls with the vinegar and orange juice should have started to fizz and became bubbly.
When the baking soda (a base) combined with the vinegar and the orange juice (the acids) a chemical reaction occurred and a new substance was created carbon dioxide.
The fizzing and bubbles that you see are the carbon dioxide begin released.
In the bowl with only water now bubbling or fizzing occurred, why? This is because water is neither a base or and acid. It is a neutral property.
Experiment 3 Broccoli and Baking Soda
*parent/guardian assistance required
In this experiment you will cook broccoli florets in an acid (lemon juice) and a base (baking soda)to see what happens.
What happens when you cook a vegetable in an acid or a base?
What do think think will happen if you cook broccoli in lemon juice (acid)? What do you think will happen if you cook broccoli in baking soda (base)?
- 3 cups of water
- 3 small saucepans
- 1 1/2 cups frozen broccoli florets
- 1 tablespoon lemon juice
- 1 teaspoon baking soda.
As with any project that requires a stove, adult supervision is required.
Step 1: Pour 1 cup of water in each of the saucepans.
Step 2: Pour 1/2 cup of the frozen broccoli florets in each of the saucepans.
Step 3: Pour 1 tablespoon of lemon juice in the first saucepan, Pour 1 teaspoon of baking soda in the second saucepan, pour nothing in the third saucepan.
Step 4: Let the broccoli cook for 7 minutes.
Step 5: Watch what happens and record your results.
The broccoli cooked in the baking soda (the base) will be the mushiest and a bright green color. The broccoli cooked in the lemon juice (the acid) will be a yucky olive green color. The broccoli cooked in the water will stay it’s natural green color.
Why did the color change?
Green vegetables are rich in chlorophyll. Chlorophyll is what gives vegetables and grass their green color.
When an acid (the lemon juice) was added to the water to cook the broccoli a chemical reaction occurred between the acid and the chlorophyll, that chemical reaction caused the broccoli to turn that yucky olive green color.
When baking soda (the base) was added to the water to cook the broccoli the broccoli became mushy, why? The baking soda destroyed the cell walls of the plant (broccoli) causing to to become very mushy.
Nothing happened to the broccoli cooked in the saucepan with just water because water is neither an acid or a base. It is a neutral property.
Experiment 4 Milk Glue
In this experiment, children will learn two ways to turn milk into glue. Try them both to find out which one makes a better glue. Follow the step-by-step directions below to make your very own milk glue.
How do you turn milk into glue?
- 1 1/2 cup milk
- 3 teaspoons of white vinegar
- baking soda
Step 1: Pour your 1 1/2 cups of milk into the pan over medium heat. Let the milk heat up until it is warm (never leave children unattended while using the stove).
Step 2: Once the milk is warm add the 3 teaspoons of white vinegar.
Step 3: Over low to medium heat stir the mixture. You will see milk lumps or curds start to appear. This happens when the liquid and solids start to separate.
Step 4: Once you have a lot of lumps strain the liquid using a strainer.
Step 5: You should be able to mold the lumps into a ball. It will be slimy.
Step 6: Put the lump back into the pan. Add a tablespoon of baking soda and a small amount of water.
Step 7: Stir and heat the mixture on medium heat until it starts to bubble.
Step 8: Once the mixture bubbles remove it from the heat and let it cool.
Step 9: It should look like a thick paste, it not continue to add baking soda and water until it is a paste consistency.
Step 10: Try using it as glue.
How did this happen? When you added the vinegar to the milk it caused a chemical reaction.
The milk separated into two parts the liquid and the solid (the milk lumps or curds).
The curds or lumps are the milk protein called casein. Casein is a long molecule that bends like plastic forming a natural glue.
When you added the baking soda (a base) to the vinegar (acid) another chemical reaction took place.
The bubbles that you saw when the mixture was heating was the carbon dioxide giving off as part of the chemical reaction turning the milk lumps or curds into a sticky, paste glue.
Milk Glue Experiment #2
No heat way to try this experiment
- 1/2 cup milk
- 2 teaspoons white vinegar
- 1/4 teaspoon baking soda
- coffee filter
- 2 tall cups
- rubber band
Step 1: Pour 1/2 cup of milk into one cup.
Step 2: Add 2 teaspoons of white vinegar to the milk and stir.
Step 3: Put the coffee filter loosely over the second cup and secure it with a rubber band. The coffee filter should be drooping a little in the center.
Step 4: Slowly pour the milk and white vinegar mixture over the coffee filter.
Step 5: Let the liquid drip through the coffee filter. This takes a while I actually let the mixture drip for about an hour so It was all out.
Step 6: Once all the liquid is gone scrape off the milk lumps.
Step 7: Place the milk lumps (curds) into a bowl then add 1/4 teaspoon of baking soda. Mix well
Step 8: The mixture should become sticky and paste like. Try using it as glue.
Other Milk Glue Experiment Ideas:
Where you able to get glue from these experiments? Which experiment worked? Try changing the amount of milk or baking soda what happens? Try using whole, 2% and 1% milk which one made the best glue?