Look at the child dropping his peas into milk, or trying to imitate the way an elephant walks. Kids are natural scientists, curious about everything they encounter. As parents, our job is to help them find answers and encourage them to ask more questions. One of the best ways to do this is through science experiments. You’ll be happy to know that these easy science experiments for kids don’t require elaborate supplies or equipment and can be safely carried out at home. The experiments are paired with simple explanations so that you can easily help your children make sense of what they are seeing. You are your child’s most important teacher, and these science activities make it fun!
1. Make a Kaleidoscope of Color: Moving Milk
This experiment will bring gasps of delight from the children. It’s lovely and educational, too. Best of all, most children can do it by themselves if you put some milk in a cream pitcher for easy pouring. Another great thing about this experiment is that it’s impossible to mess up. You will get some cool effects no matter what. Also, it’s cheap to do and easy to start over. This experiment teaches the concept of surface tension.
You’ll need dinner plates, milk (at least 2 percent fat), liquid food colors, dish soap, and a cotton swab. Pour in enough milk to cover the bottom of the plate.
Drop one drop of each color of food coloring right in the center of the milk. Try not to let the drops touch each other. Put a drop of dishwashing detergent on the end of the swab. Then touch the swab to the milk right in the middle of all the drops of color. You’ll get a color explosion, and the colors won’t stop moving even if you take the swab out of the milk. Put it back in the milk in a different spot, and the movement will change.
Why It Happens
Soaps and detergents are interesting substances. Their molecules have one part that wants to join up with water and one part that wants to join up with fat. When you put detergent into water or milk, these opposing forces work to reduce the surface tension. That’s why you get all the movement on the surface of the milk. (The food coloring isn’t a part of the reaction. It just helps you see the reaction.)
When you put the swab with detergent on it into the milk, the part of it that wants to join up with fat starts to chase the fat molecules around. But since the milk contains only a small amount of fat, this reaction doesn’t last too long.
After you have watched the reaction for a while, put one more drop of detergent in the plate. If all the fat molecules have connected with soap, you won’t see any more action. If a few fat molecules are left, you may get a second color explosion.
If you have cream, almond milk, skim milk or evaporated milk in the house, repeat the experiment and see what results you get.
2. Test Your Lifting Power: The Rice Bottle Experiment
This is a simple experiment that illustrates an important scientific principle. It’s also a great experiment for you and your child to prepare together to stump a friend or sibling. This experiment is best for older kids as young children shouldn’t be trusted to use the sharpened stick that is required. Smaller children could, however, watch as you do the preparations. This experiment teaches the concept of friction.
All you need are two plastic bottles and two smooth sticks such as skewers, chopsticks or pencils. (If you use skewers, blunt the sharp ends a bit.) You can use empty water bottles or any other empty plastic bottles that you have around the house, but the two bottles should be identical. Fill both bottles with rice. You can use a funnel to make it easier. Stop filling about an inch from the top.
Next, put the lid on one bottle and shake it up. This is your bottle of “fluffy” rice. Your goal is to get as much air between the rice grains as possible. Put the lid on the other bottle and strike it repeatedly on the counter or table. This is your bottle of “heavy” rice. Your goal is to pack the rice grains together as much as possible. Watch to see if the rice level goes down. If it does, add a bit more rice and repeat. Next, start pushing the stick point first into the bottle and gently pulling it out. Push the stick in at different depths and angles. It should get harder and harder to pull out. Eventually, if you try to pull the stick out without holding on to the bottle, the bottle will lift off the table. Now you’re ready to puzzle your child’s friend.
Let your child push his stick into the bottle of “heavy” rice and gently lift it off the table. Give the friend the bottle of “fluffy” rice and a stick and invite him to do the same. His stick should slide out of the rice without lifting the bottle.
Why It Happens
In the bottle of packed rice, many grains of rice are pushing hard against the stick. This creates friction which holds the stick in place. The bottle of fluffed-up rice contains more air between the grains and creates less friction when the stick is pulled out. It’s interesting that the “heavy” rice is the one that is easiest to lift off the table.
If your child’s friend repeatedly pushes the stick in and pulls it out in an attempt to replicate the feat, the rice may become more densely packed, and the trick may work.
Try this experiment using different sticks. If you use a large bottle and a thin stick, the combination of the weight of the rice and the slenderness of the stick may keep the experiment from working. Why might that occur?
You can also try the experiment with different types of grains. Does it work with instant rice? What about with quinoa, barley or steel-cut oats?
3. Create a Cushion of Air: CD Hovercraft
Scientist learns from their failures, and this experiment may not work perfectly the first time. So what? Your kids will get to try their hands at troubleshooting. And if it does work, it’s kind of magical. Children can help with all stages of this project except perhaps the glue. This experiment works with friction and force.
You’ll need an old CD or DVD, a medium-sized balloon and a water bottle cap that you pull out to open. You’ll also need glue. Hot glue dries most quickly, but any type of quick-setting glue will work. Close the lid of the bottle cap and glue it over the hole in the CD. Let it dry. Blow up the balloon, twist it shut and slide it over the cap. (This step can be a little tricky. It’s easiest if one person holds the balloon twisted shut and the other puts the mouth of the balloon over the cap.) Once the balloon is in place, you can untwist it.
Place the contraption on a smooth table, countertop or other very smooth surfaces. Without dislodging the balloon, simply pop open the bottle cap. Air should flow from the balloon through the hole in the CD, and the CD should slowly glide across the surface.
Why It Happens
The force of the air rushing out of the balloon creates a thin cushion of air under the flat CD so that it hovers just above the surface, much as the pucks on an air hockey game float above the surface. It works because the cushion of air eliminates or greatly reduces the friction between the two surfaces.
If your hovercraft doesn’t move, give it a gentle push. Here are some other problems that can occur and how you can fix them.
- Air Leakage. If you did not achieve a good seal around the cap, air will flow out on top of the CD rather than under it. What could you use to achieve a better seal?
- Warped CD. If your CD isn’t perfectly flat, the air will not escape evenly around the CD to create the air cushion. Is this a fixable problem?
- Tipsy Balloon. If your balloon falls to one side, it may raise one edge of the CD and drop the other so that it drags on the surface. Can you improvise a lightweight collar to hold the balloon upright?
You can also try replacing the CD with other materials, such as a paper or foam plate. Will shapes other than circles work, too?
4. Make Layers of Shades: Density Columns
Almost everyone knows that when you put oil and water together, the two don’t mix, and the oil ends up floating on the water. This experiment takes that knowledge a few steps forward by exploring how other liquids behave. The end product will be prettier if you color a couple of the layers with food coloring, but that step isn’t necessary for the experiment. Older kids should be able to do most of this experiment on their own with supervision. Younger ones will have trouble pouring the liquids carefully, but they can mix the food coloring into the liquids during the set-up phase. This experiment teaches the concept of density.
Get ready for the experiment by pouring these liquids into separate cups: honey, light corn syrup, dishwashing detergent, water, vegetable oil and rubbing alcohol. Pour out about half a cup of each. If you want one more layer, you can use lamp oil, but since it is flammable and since most people don’t have it around the house, many parents leave it out. The corn syrup, water, and the rubbing alcohol can be colored if you like to make a more striking display. You can also make the dish detergent a more vibrant hue if you would like.
You will need a glass container to hold your liquids. A cylinder-shaped container is ideal, but you can also use a large glass jar or other clear containers. If you have a turkey baster, it will come in handy for the last few layers, but it’s not absolutely necessary. You can use a straw instead.
You’ll be adding liquids gently and slowly to your glass container. The first three liquids should be poured into the center of the container, not letting them touch the sides. The next layers are added by letting them run slowly down the side of the container, using a turkey baster or straw to dispense them. Always give each liquid a minute to settle before going to the next step.
- Pour the honey into the center of the container, trying not to let it touch the sides.
- Pour the corn syrup next, again keeping it away from the sides.
- Add the dish soap in the same way. This liquid is thinner, so be sure to pour extra slowly.
- Add the water next. This time use the baster or straw and let the water run slowly down the side of the container.
- Do the same thing with vegetable oil. If are using the baster, you’ll need to wash it between steps. If you’re using a straw, wash it or use a fresh one.
- Use the baster or straw to add the rubbing alcohol.
- Using the baster or straw, add the lamp oil, if you are using it.
You should end up with a container of beautifully separated liquids. If you poured a little too fast, you may have a bit of mixing between some of the liquids, but they should separate after sitting a bit.
Why It Happens
The different liquids in the column have different densities. Density is equal to mass divided by volume. The very dense liquids will stay at the bottom of the column, and the less dense ones will want to hang out at the top.
Here are some ways to extend this experiment:
- Watch the column for a day or two and see if any changes occur. Eventually, most density columns will separate into one watery layer and one oily layer.
- Drop items into the column and see how far they sink. Try a coin, a hard bouncy ball, a grape, a cherry tomato, a rubber band, and a ping pong ball.
- Stir the column up and see how well it separates back out.
5. Melt That Shell: Naked Eggs
This is an interesting experiment that takes a day or so. Start it one day after school, and it should be complete the next day when the kids get home from school. In some cases, it may take a day or two longer. This experiment is safe and appropriate for kids of all ages. It’s super simple but can have a messy side! This experiment utilizes a chemical reaction.
You need an egg, plain vinegar and, a clear glass. Carefully slide the egg into the glass and pour vinegar to cover.
You will immediately begin to see tiny bubbles on the exterior of the egg. After 24 hours or so, check to see if the shell has completely disappeared. If so, remove from the vinegar and rinse off. If not, wait a little longer.
When the shell is all gone, take the egg out of the vinegar and wash it off. The membrane is all that is holding the egg together. Hold it up to a flashlight and see if you can see through it. You should be able to see the yolk moving around. That tells you that the egg is still raw. You can bounce this egg, but it will burst, and you will have a mess. Do this part of the experiment outside, where you can hose off the egg, or bounce it in the sink or inside a baking pan that will catch it when it breaks.
Why It Happens
Vinegar is basically acetic acid, which reacts with the calcium carbonate in the eggshell, releasing little bubbles of carbon dioxide. This is a chemical reaction. Eventually, the shell will be completely dissolved.
Before you start the experiment, choose another egg that is very close to the same size as the egg you are going to submerge. Put a mark on the egg and put it back in the fridge. When you take the naked egg out of the vinegar, compare it in size to the twin egg. The naked egg should be slightly larger. How did that happen? Shouldn’t the naked egg be smaller since it is missing its shell? The answer lies in the permeability of the egg membrane.
6. Make It Sparkle: Epsom Salt Crystals
There are a lot of solutions for making crystals, but this method yields the fastest results and is safest for kids. You’ll want to handle the hot tap water, but the kids can do the rest. This experiment teaches about solutions and about crystals.
You’ll need Epsom salts from the drugstore, food coloring, water, and some clear glass containers.
Use a clear container such as a canning jar to mix half a cup of Epsom Salts in half a cup of hot water from the tap. Stir for at least two minutes. A little of the salts may stay at the bottom, but that’s no big deal. Let the kids put in whatever food coloring they like. Then put the jar in the refrigerator.
Mix up a couple more jars. Put a plastic bottle cap in one and another small item in the other. Put them in the fridge, too.
Check the jars in a few hours, and you should already have crystal growth. Compare the plain jar with the ones containing items. Did the item placed in the jar affect the crystal growth? How?
Why it Happens
In this experiment, you first create a solution by dissolving the Epsom salts in water. The water is the solvent, and the salts are the solute. Epsom salts are actually magnesium sulfate. When you cool the mixture quickly, the molecules of magnesium sulfate start to run into each other and join together. This method produces thin, needle-like crystals.
Epsom salts crystals grow the fastest, but you can also use borax, table salt, and sugar to create crystals. You can make rock candy with sugar. You can form borax crystals around pipe cleaners or cotton balls to create ornamental objects. You can also look at the crystals with a magnifying glass and observe that crystals from different solutions are differently shaped.
7. Listen to the Music: Glass Xylophone
Most kids at one time or another have experimented with striking a water glass to make a tone. This experiment takes the process a step or two further. Adjust the steps to fit your kids’ level of interest and ability. This activity is not suitable for very young children since it uses glass. This experiment teaches about sound.
Find five identical water glasses. Line them up and fill them with different levels of water. Start by putting just a half inch or so in the first glass. Then fill the fifth glass almost to the top. Fill the middle glass to a level between the first and last glasses. Then fill the second and fourth to levels that are the middle of the glasses on each side. By using this method, you should create a crude musical scale. You can also add food coloring to the water so that each glass holds a different color. This isn’t necessary for the experiment but does add eye appeal.
Let the children take turns gently hitting the water glasses and listening to the tones. Young children should be given pencils or other safe objects to use for striking. With older children, you can try different implements to see what creates the best tone. Discuss which glass makes the highest tone and which the lowest and see if the children can guess why.
Why It Happens
The glasses vibrate when struck, producing sound. The water in the glasses slows down the vibrations, creating a lower tone. The glass with the most water will make the lowest note.
If your children are older or are interested in music, you can add three more glasses to create a simple xylophone. Challenge them to play an easy tune such as “Twinkle, Twinkle, Little Star” or “Happy Birthday.” You can even try to tune the glasses using an online tuner.
8. Pump Up the Volume: A Cloud of Soap
This experiment has a lot of wow power. It’s simple, too, since you need only a bar of Ivory soap and a microwave. It’s safe as long as you don’t let the kids take the soap out of the microwave too quickly. It will leave your microwave with a rather strong smell for several hours. This experiment teaches about physical reactions versus chemical reactions and about volume.
Be sure you have a fresh bar of Ivory soap. No other brand will work. You also need a microwave and the largest plate that will fit in your microwave.
Simply put the soap in the microwave and turn it on for 90 seconds. Let the children watch through the door. The soap will expand until it is several times its original size! Let it cool for a few minutes before taking it out of the microwave. Let the kids touch it. It looks fluffy like a cloud but is actually quite crumbly.
Why It Happens
You may know that Ivory soap is advertised with the tagline, “It floats.” That’s because a lot of air is whipped into the soap during manufacture. When you heat the soap, the tiny air pockets expand, making the bar puff up. This is a physical change, not a chemical reaction. Although the mass of the soap has not changed, its volume – the amount of space it takes up – has changed quite a lot.
If you have wondered what you can do with the soap, it is still fine to use. Put a few pieces in a bowl by the bathroom sink. You can also use it in homemade laundry soap. If you want to involve the kids, you can put a little water in it and let them mold their own soaps. The mixture won’t be easy to work with, however, and if they touch their eyes, the soap will really burn.
Keep on Learning!
One of the great things about science experiments is that they tend to lead to more questions. Those questions may lead to further experiments, or to other forms of exploration. You play an important role for your children as they make these forays into the world of science. Their curiosity is the driving force, and you are at the controls, making sure that they stay safe and challenged. Happy exploring!