Science Experiments

Here are a number of science experiments to enhance your children's scientific skills and to encourage their interest in science. Summer is a great time to do these experiments with your children to build their interest in science. Be sure to choose those that are age-appropriate for your children. Some experiments should only be done under the supervision and with the help of adults.

Growing Pineapple

Science experiments when children get to grow things are always fun. Did you know that no matter where you live your children are able to grow pineapples? First you need to buy a whole pineapple at the store then an adult needs to cut the top off the pineapple. The top of the pineapple includes the green top and about 2 inches of the fruit. Let the top dry for about a day and a half -- which is about 36 hours. Then your children are ready to plant. They need a pot full of soil. After the top has been planted place the container in a warm location about 72 F. Your children need to keep the soil around the top of the pineapple damp but not too wet. The new pineapple will be developing on the top of a long stem. You may need to support the new pineapple by sticks or secured upright with string when the fruit grows large. However, if there is no sign of a new pineapple you will need to put the whole container inside a large plastic bag and put a rotting apple or lemon inside the bag. Close the bag up and let it sit for several days. The rotting fruit will help stimulate fruiting. Your children may need to replant the pineapple to a larger container.

Finding the Plant

Soak several lima bean seeds in a container of water overnight. The next day pick some of the seeds and place them on a countertop or some paper. An adult should help you to cut open the seed. Now look inside. What do you see? Using a magnifying glass with help you to be able to better see the three basic parts of the seed: the seed coat, the food storage area, and the embryo.

Popping Bag

Get two plastic bags and fill both bags with dry bean seeds. Close one of the bags and then fill the other bag with water and close it. Place both bags outside in a sunny location. After several hours in the sun the bag with the water will begin to sell up. It will eventually expand with seeds popping the bag open and seeds continuing to pop out of the bag.

Floating Grapes

In science there is always a little bit of magic. Can a grape float in the middle of a glass of water? First get all the materials you will need to answer the question: 4 drinking, masking tape, marker, 4 larger glass or measuring cup, water and sugar, grapes, and a spoon. Have your children first practice this experiment before they perform before a live audience. Begin by having the children use the masking tape and marker to number the four glasses. Now fill the measuring cup with water and stir in enough sugar so that a grape will float at the surface of the water. The undissolved sugar will float to the bottom of the measuring cup. The children fill glass #1 with plain water from the tap to the top of the cup and then place one grape into glass #1 and see what happens.

Now take the special sugar water that you already made that is in the measuring cup and pour it into glass #2. Fill the glass to the top and then place one grape into the sugar water solution. What did you see happen? Moving on to glass #3 fill the glass half-full with the special sugar water solution from the measuring cup now comes the tricky part you will be filling the rest of glass #3 with plain tap water. This must be done very carefully and slowly so that the plain tap water will not mix with the heavier sugar water. Place a spoon in the 1/2 cup of sugar water then pour in the plain water having it hit the spoon inside the glass. This step might take several tries before it is mastered. Finally, you should find that you can't tell the difference between the two liquids in Glass #3 now finally place a grape in glass #3.

Now as a scientist you need to come up with the right sugar water solution so that when fully mixed, will cause the grape to float in the middle just like in glass #3. What secret mixture did you come up with? How much sugar and how much water was needed to make the grape float in the middle of the glass.

Building Scientific Curiosity

Curiosity is the one trait that all scientists share. Sometimes, this trait gets derailed in science classes at schools when children seek solely to find the right answer to questions. Here are some activities that will not only appeal to your children's inquiring minds but will also build their interest in discovering more about their everyday world.

  1. Explore items in the house or backyard with a magnifying glass.
  2. Take an object like an old clock, radio, telephone, flashlight, or pair of binoculars apart.
  3. Lie on your backs and observe the night sky.
  4. Choose a variety of items and then determine if they float or sink.
  5. Pull up weeds and study their parts.
  6. See what household items stick to a magnet.
  7. Compare leaves or rocks or insects.
  8. Put leftovers such as a slice of bread, coffee grounds, and tomatoes in both a dark cupboard and the refrigerator to see which ones grow mold faster.
  9. Learn how to read a sun dial.

Growing a Potato Plant

Find a potato that is starting to sprout. Put four toothpicks evenly in the end away from the sprouts about 1/3 down from the top of the potato. Put the sprouted end in a glass full of water. The potato will rest on the toothpicks. Keep the glass in a warm, sunny spot. Add water, as needed, to keep the glass full. Once the potato plant has leaves, it needs to be transplanted to a pot filled with potting soil to keep growing. Remove the toothpicks before planting. When the soil in the pot is dry, it should be watered.

The Movement of the Ocean

This experiment will let your children bring the ocean home to your house. They should pour about two tablespoons of cooking oil into a small, clear pop bottle, and then fill the rest of the bottle to the brim with water. Add a few drops of blue food coloring before putting the cap back on the bottle and laying it on its side. Next, have them tip the bottle back and forth. Your children will see ocean waves and also discover that oil and water do not mix. The oil floats to the top because it has a lower density.

Butter for Your Bread

In about ten minutes, your children will be able to turn normal or heavy whipping cream into butter, but they must do a lot of shaking. They should pour some cream into a jar. Then put the lid on tight, and shake the cream back and forth until it thickens. The globs are butter, and the liquid is buttermilk. How did this happen? When the fat and the protein in the cream move around, they stick together.

No Time to Wait for Fruit to Ripen

Help your children discover how to speed up the process of ripening fruit. They can use pears, bananas, peaches, or tomatoes that are not quite ripe. Have them place a few pieces of the fruit into a paper bag along with an already ripe apple or banana peel. Then the bag should be closed tightly. Within a day or two, the fruit will be ripe. Why does this happen? Ripening fruit releases ethylene, a natural hormone, as a gas. The bag traps the gas and causes the fruit to ripen.

Making Raisins

Do your children know that raisins are just dried grapes? This experiment will help your children see how a juicy grape turns into a dried-up raisin. The process that does this is evaporation. Start by washing a bunch of grapes in cold water to clean them. Then place individual grapes on a paper towel covering a wire rack. Cover them with another paper towel. Place the grapes outside in the sun. You may have to weight down the paper towels to keep them from blowing away. Depending on the temperature, it can take a week or more to turn the grapes into raisins. Sweet grapes work best. The raisins will be very tasty. In the same way, plums can be turned into prunes. Put your raisins or prunes in a sealed plastic bag to keep them fresh.

Shrinking People

Believe it or not, people don't stay the same height throughout a day. They actually shrink. Why does this happen? Between the vertebrae in our backs, there are soft cartilage discs. As we stand, liquid in these disks is squeezed out. It will return at night as we sleep. Begin this experiment by measuring your children's height at the start of the day. Measure their height throughout the day and again before bedtime. Have them determine how much they shrank and how long it took for them to start to shrink? Expand this experiment by having your children measure other people to answer these questions: Do young people or old people shrink more during a day? Do tall people shrink more than short people?

Reaction Time

Race track drivers, baseball players, and many other athletes have very fast reaction times. Have your children hold a dollar bill up in the air in one hand, and then drop it on its side so it flutters as it falls. They should not have trouble catching it with their other hand. Then have someone else do the dropping. The lower they catch it, the slower their reaction time. In fact, they may not even be able to catch it. This is because their brain sent a signal to their hand when they dropped the dollar bill. They did not have this information when someone else dropped the bill.

Telling Time

People were telling time with some accuracy long before they had clocks and watches. One way was by using a water clock. Your children can make one by punching a small hole no larger than the size of the point on a ballpoint pen in the bottom of a plastic container (help younger children do this). The children also need to make four marks on the container the same distance apart. The hole should be covered with a piece of duct tape, and the container filled with water. Next, put the container in the sink, remove the tape, and have your children determine how long it took for the container to empty. To complete the experiment, they need to place tape over the hole again and refill the container with water. This time have your children measure the time it takes the water to drop from one line to another. Ask them how they could use this container as a clock and why they think that the water took less time to move from line to line as the container emptied. They can also use a large container and make marks every hour as the water level falls.

Just like was done in the past, your children can learn how to tell the approximate time of day by where the shadow of a tree falls. First, they need to find a tree (or pole) that is in the sun most of the day. Then several times during the day, they should go out and mark the end of the shadow with a rock and record what time it is. The next day they can go back to the tree and determine what the time is by checking the time on the rock where the shadow ends.

Baking Cookies and Cakes

Help your children bake three or four small cakes. Make the first cake according to the recipe. Then leave either salt, egg, or baking powder out of the remaining cakes. When all the cakes are baked, the children should cut them in half and study what they look like. They should also taste each cake. Have them observe and think about what leaving out each ingredient did to a cake so they can learn something about food chemistry.

This time your children will make a batch of cookies with your help. On one cookie sheet, they will form small cookies and on the other monster-size cookies. Then they will time how long it takes to bake each size of cookie to determine if mass affects baking time. Finally, they can enjoy the cookies.

Deciding What to Wear

Do your children know whether it's smarter to wear a black or white shirt on a hot day if they want to stay cooler? Help them learn whether black objects or white objects heat up faster with these two experiments. To expand the experiments, other colors can be tested.

Take two thermometers outside, and lay them on the ground. Cover one with a piece of white paper and the other with a piece of black paper. Go back in 30 minutes and read the temperature of each thermometer to discover which color heated the thermometer faster.

Have them test this again by filling a can painted black and one painted white with the same temperature water. Each can should be covered with a piece of paper that is the same color as the can and placed outside for an hour. Then the children should remove the paper, and put a thermometer in each can to determine its temperature.

Warming up the World

Sunlight warms the world. But does it warm up land or water faster? Use two identical small white cups to find out. Fill one with water and the other with dirt. Put both in the freezer for 15 minutes to get them to similar temperatures. Now take them outside and place them in full sunlight. After half an hour, use a thermometer to find out the temperature of both cups. Ask your children why they'd rather be in the water or on the beach on a hot summer day.

Overflowing Water

Water molecules are attracted to each other. Fill a cup to the brim. Then start adding more water an eye dropper at a time. After 10 to 20 drops of water, look at the top of the cup from eye level. You'll see that the water is now above the top of the cup. This is because the drops of water are held together by surface tension. If too many drops are added, the tension will not be strong enough to stop the water from spilling over. Learn more about how surface tension works by seeing how many drops of water can be dropped one at a time on a coin (penny, nickel, dime) before the water spills off the surface of the coin.

Hiding Animals

Animals often use camouflage so they can blend into their surroundings. Now your children can see how it works. They will need construction paper in three different colors. The children should cut one sheet of each color into two inch squares. Then, while one child closes his or her eyes, the other lays the cut-up squares on a piece of paper of one of the colors in a random fashion. The other child then picks up as many squares as he or she can in 5 seconds. Typically, the colors picked will not be the same as the sheet of paper because they are camouflaged just like chameleons.

Investigating Acid and Base Foods

Help your children find out if a food is an acid or a base by using the liquid from a jar of pickled red cabbage. They should place some of the liquid in several saucers before adding very small bits of food or juice. If the food turns pink, it is an acid. If it turns greenish-blue, it is a base. Have them try this with tea, orange and lemon juice, vinegar, ground coffee, and baking soda.

Freezing Time

Does the freezing time of water vary with what is put in it? Fill two identical containers with a cup of water, and then put a tablespoon of shortening (solid cooking fat) in one of them. Next, both containers go in the freezer, time how long it takes the water in each one to freeze.

In cold climates, salt is put on the roads to melt ice. Does it work? Find out if salt affects how fast ice melts. Put the same amount of water in two teacups. Add a tablespoon of salt to one of the cups, and then add one ice cube to each cup. Soon, you'll see if salt affects the melting of ice.

Decaying Fruit

Which fruit decays the fastest? This is fun because your children will see the fruit blow up a balloon. When fruit decays, bacteria multiply and multiply as they eat up the fruit. In processing the food, the bacteria give off gas.

Mash a ripe banana and put it into a bottle. Then place a balloon over the mouth of the bottle, and put the bottle in a warm, sunny place. Measure how far the balloon inflates each day for a few days. Do the same thing with other sweet fruit, such as grapes, apples, and oranges to answer the experiment question.

Learning More about Yourself

Through simple experiments, children can learn a great deal about how their bodies work. Is one eye better than two? You'll need an eye patch and a fairly small ball for this experiment. Two children should stand several feet apart and toss the ball back and forth ten times. Older children should catch the ball with one hand. Then one child should put on an eye patch. Again, the children should toss the ball to each other. Total how many times the child caught the ball with and without the eye patch. Then have the other child use the eye patch.

The blind spot is the area on the retina where there are no light receptors. Have your children draw a small circle about 3" from a small cross on a piece of paper. They should close their left eye and stare at the circle from about 20" away. As they bring the paper closer, the cross will disappear from sight. This is when the cross falls on the blind spot of their retina. They can repeat the experiment by closing their right eye.

An afterimage is what our eyes continue to see after we have stopped looking at an object. Cut a 3" x 5" card in half for your younger children. In the middle of one card, they should draw a lion. In the middle of the other, they should draw a cage. The two cards should be taped together at the end of a pencil or small thin stick so one picture is visible on each side. The fun begins when they start rubbing the pencil quicker and quicker between their palms and the lion appears to be in the cage. Have them repeat the experiment by drawing a man and the moon. Each time they'll see images after they are gone.

Is your skin the same everywhere? Make a big, black area of about 3 inches by rubbing a soft pencil on a sheet of paper. Put a finger on the spot until it picks up a big smudge. Then pick up the smudge with a piece of scotch tape and press it onto a piece of white paper. Do the same with other parts of your body? Do your skin prints differ?

How hard is your heart working? Take your pulse lying down, and then after doing these exercises: sitting, standing, and jumping 10 times. Does your pulse rate change with what you do?

Whose heart beats faster? Take your pulse, a parent's pulse, and a grandparent's pulse? Was there a difference in the rate?

Experimenting with Gravity

Gravity causes all objects to be pulled toward each other. Because Earth is the biggest object, it has the strongest pull of gravity. It is gravity that holds us on Earth and causes balls thrown in the air to fall to the ground.

How does gravity work? Place a marble in a bottle. Turn the bottle upside down. What happens? Again, place a marble in a bottle. Move the bottle so the marble starts going around inside it. Keep moving the bottle and gradually turn the bottle on its side and then upside down? Did the marble fall out of the bottle? It shouldn't have. Centrifugal force should have pulled the marble away from the bottle neck and overcome the gravity that would cause it to fall out.

Can you feel gravity? Jump up from the ground to the first step of a set of stairs. Then jump down. Which was easier to do? If you didn't feel a difference, try jumping down with your eyes closed, but be very careful. Gravity is pulling you down toward Earth – making it easier to jump down.

Will shape affect how fast an object falls? Climb up on a chair or stepstool with adult supervision, extend your arms, and drop equal sized sheets of paper to the floor. Did they arrive at about the same time? Now, drop a sheet of paper and a crumpled up sheet of paper. Did they arrive at the same time? You should conclude that shape does affect the rate of fall of an object.

Learning from Balloons

It is possible to learn about several scientific principles using balloons. Your children will need your help on these experiments in order to do them easily and safely.

Does air expand when it is heated? Blow up a balloon and measure the distance around it at its widest point (circumference). Next, turn on a lamp and hold the balloon above it for 2 to 3 minutes. Then measure the distance around the balloon's circumference again. What happened to the size of the balloon?

Ask your children if they think that it is possible to stick a pin in a balloon without popping it. Blow up a latex balloon until it is about three-quarters full of air and tie off the end. Next, cut seven pieces of strong, sticky tape and secure each one firmly to the outside of the balloon. Try to space them evenly. Then carefully stick a straight pin through the middle of each piece of tape. Why didn't the balloon burst? (The sticky tape forms a seal around the pin.)

Play the water toss balloon game. Have teams of two players toss balloons filled with water back and forth. They are to go back one step after each successful catch. Ask them what they think is the secret of a successful catch. (Answer: moving their hands backward as they catch so they are not abruptly stopping a balloon's momentum.)

Learning about Buoyancy

While taking a bath, Archimedes jumped out of the bathtub and yelled, “Eureka” because he had discovered the principle of buoyancy. Your children can investigate how buoyancy works. They'll need a bucket or wastebasket of water and modeling clay. They should form a ball with the clay and then drop it in the water. The ball will sink. They should then keep molding the clay until they find a shape that floats in the water. At this point, the clay is floating because the water pushes up on it with a force equal to its weight. Have them experiment with different shapes to see which one floats best (is more buoyant). They can expand the experiment by placing pennies on different clay shapes to see which one will hold the most pennies before it sinks.

Finding Your Dominant Side

Children can have fun trying to determine their dominant side. Most will be either right- or left-sided. Some will have mixed dominance. These test results may or may not be accurate.

Ask your children to kick a ball as hard as they can. Then ask them to step on a coin on the floor. The foot that they use is probably their dominant foot.

Ask your children to close their right eye. Then they should raise their arm and use their thumb to sight a distant object. Next, they open their right eye. If their thumb appears to them to move right, their right eye is probably dominant. Otherwise, their left eye may be dominant.

Most children are right handed. However, many of them have dominant left thumbs. Ask your children to fold their hands together. The thumb that is on top is likely to be the dominant one.

Have your children tell other children that they want to tell them a secret. The ear that they offer is probably their dominant ear.

Experimenting with Air

Your children can't see air, but they can learn more about it through experiments. Help or supervise younger children with the next two experiments as they use hot water.

Have your children find a large plastic bottle like a soda bottle. Hot tap water should be poured into the bottle until it is about half-full and then swished around in the bottle for about a minute. Pour the water out of the bottle, and immediately screw the cap on tightly. Watch the bottle collapse. What has happened is that the air in the bottle is warmed by putting the hot water in the bottle. When the bottle is capped, this warm air quickly cools. Cool air takes up less room than warm air. The bottle collapses to fill the space. It has been pushed in by the outside air pressure on all surfaces of the bottle.

Your children will discover that eggs contain air. Have them place an egg in a small, deep bowl and then fill it with hot tap water. Right away, your children will see tiny bubbles emerge from the egg to the top of the water. The water has warmed the air in the egg and caused it to expand. The warm air then pushes its way out of the egg. When the experiment is finished, the egg should then be cooked.

Moving Water in Plants

Your children can see how water gets from the roots of plants to all the other parts of the plant. The process is called capillary action. They can use 3 white carnations or celery stalks with leaves. They also need three tall, clear glasses and red, yellow, and blue food coloring. Mix one color into each of the glasses. The color should be strong. The children then place the stem of a flower or celery stalk in each glass. The plants should then be placed outside in the sunlight. Within a day or more, they will see that the color has traveled up the stems of the plants.

Your children can expand this experiment by having you split the stem of a flower. Then one stem can be placed in one color of water and the other in a different color. Your children will be surprised to see that the flower will have both colors.