Home Science Experiments for Grandparents and Grandkids

  • 01 of 09

    Do Science at Home for Extra Learning and Fun

    science experiments at home with grandchildren
    The grandchildren will love playing scientist, and they'll also learn a lot. Westend61 / Getty Images

    Kids love experiments, and few kids get their fill in crowded science classrooms. That creates a perfect opportunity for grandparents to step in. The next time the grandkids visit, be ready with the raw materials for a home science experiment. They'll love it! And, if you've done your homework, you'll be ready to engender some real learning.

    Be Prepared

    To make the most of your experiment, you'll need to prepare ahead of time. The first -- and most important -- reason to prepare is...MORE safety's sake. You don't want anything bad to happen to the grandchildren on your watch. The second reason is also important. Science experiments shouldn't be mere parlor tricks. They should add to the grandkids' knowledge of their world. Although you want the little scientists to draw their own conclusions, you'll need to be well-prepared to point them in the right direction.

    If you're nervous about safety, be aware that some science experiments don't require any mixing of chemicals or heating things up. Check out the optical illusion and kaleidoscope pages.

    Lessons to Teach

    Emphasize to the grandchildren that they are never to engage in experimentation on their own. Point out to them that there are substances in the average home that are deadly when mixed (chlorine bleach and ammonia, for one example). This is a good opportunity to talk about the scientific method. Scientists ask a question, do research and predict what the outcome will be before they ever begin an experiment. Predicting outcomes enables scientists (and grandparents and grandkids) to be prepared.

    What to Buy

    You can do science experiments at home without buying special kits. It is fun to have test tubes, beakers, stirrers and other gadgets that typically come with the science kits, but you can order them online without the other stuff. If your purpose is to make a kid fall in love with science, cool accessories are a plus. Safety goggles are a smart precaution but also will add to the element of fun. Make a lab coat from a man's white shirt, or buy a vinyl lab apron for a few bucks. Get one for Grandpa, too.

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  • 02 of 09

    Create a Rainbow With a Density Column

    create a density column easy science experiment for grandchildren
    A density column is thrilling to create because of the beautiful colors, but it can be a tool for learning, too. S. Adcox

    Besides being pretty, density columns can be used to teach some really critical scientific principles.

    What to Do

    Decide what container you are going to use for your density column. A glass column is ideal, but almost any type of clear glassware will do. Gather the following liquids: honey, white syrup, liquid dishwashing soap, water, vegetable oil and rubbing alcohol. You'll need a quarter cup to half a cup of each for a wine glass or similar container, or more for a larger container. Use...MORE food coloring to color each liquid except the honey and the vegetable oil, which are difficult to color.

    Carefully pour the honey into your container, trying not to hit the sides of the container. Next pour the syrup, and continue with all the liquids in the order listed, trying to disturb the liquids as little as possible. If the layers mix a little, they will separate more clearly as they sit. In the picture above, the honey and syrup aren't clearly separated, but they did separate after they sat for a while. When the grandkids finish your density column, put it in a light-filled window and enjoy!

    Science to Learn

    The density column works because each of the liquids has a different density. To help kids understand density, tell them that it is the heaviness of an object relative to its size. It may help to use an example. If you have a rock and a marshmallow that are the same size, their volume is the same, but the rock has greater density.

    Practical Matters

    If you don't have all the liquids, don't worry. The picture above was made with only five layers. If you want to add a seventh layer, use lamp oil for the top layer. I didn't include it because very few households have lamp oil.

    The alcohol and the lamp oil, if you use it, are flammable. Don't put them near a heat source. Keep the density column away from younger children who might be tempted to drink it.


    If you did the Ivory Soap experiment on p. 2, remind the grandchildren that Ivory soap floats because it has air whipped into it, making it less dense than water. A good elementary measure of density is whether something will float. Have the grandchildren experiment with various items to see which ones will float.

    What Can Go Wrong

    After the density column sits for a couple of days, some of the layers may mix a bit. Two layers may even switch places. If this occurs with your density column, ask the grandkids to hypothesize why it happened. Since there is a lot of variation between different brands of the various products used, it's difficult to be sure, but it probably happened because part of one or more of the liquids evaporated, causing a change in density.

    This activity is suitable for school-age grandchildren.

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  • 03 of 09

    Grow Something Gross in a Petri Dish

    help the grandchildren grow microorganisms in a petri dish
    Growing microorganisms in a petri dish is a great way to engage the grandkids' interest in science. Ableimages / Getty Images

    Want to get the grandchildren to be more careful about handwashing? Here's an experiment that will show them that microorganisms are everywhere.

     What to Do

    To grow bacteria and other microorganisms, you' need a substance that the bacteria can't digest. The substance used most often is agar. You can order petri dishes online and make your own agar gel to fill them, but you can also buy them pre-filled, which is probably best for a grandparent's purposes. You'll also need clean...MORE cotton swabs. 

    Once your petri dishes are ready for use, store them in the refrigerator. Petri dishes are stored upside down, both before and after use. That's because otherwise condensation will form in the lid and drop onto the growing surface.

    When you are ready to begin the experiments, take the dishes out of the refrigerator and let them come to room temperature. Next you will guide the grandchildren in transferring microorganisms from common household objects to the dishes. They can use two methods to do this. One is to press an object against the surface of the agar without breaking the surface. The other is to use a damp cotton swab to collect bacteria from surfaces such as doorknobs and remote controls. The swab is then drawn across the surface of the agar, again without penetrating or breaking the surface. The entire surface of the agar should be covered with invisible stripes where the bacteria has been deposited.

    Close each dish after it has been processed. Use a Sharpie or other method to label each dish with the source of the sample. Tape the dishes closed and place upside down in a warm, dark place. In a couple of days, growth will be seen -- and sometimes smelled! Observe for a few days.

    When it is time for disposal, seal the dishes in plastic zipper bags and put in the trash. Remember -- these are common household microorganisms and thus are unlikely to be really dangerous. Still, they have had a chance to grow, so you won't want to take any chances. You can even put a little bleach in the zipper bags if you want to be extra-cautious. 

    What Can Go Wrong

    The only thing that really happen is that the bacteria can fail to grow. This could be because the grandchildren didn't get a good sample on the surface, because the growing medium was defective in some way or because the temperature wasn't warm enough. If you think the temperature was the issue, look for a warmer spot, or create an incubator through shining a small lamp on a box or other enclosed area. 

    Science to Learn

    Older grandchildren may be able to search online and actually identify some of the cultures that grow. It's also interesting to see which surfaces grow the most microorganisms, although it's important to teach the grandchildren that a real scientist would have to run many carefully controlled tests before reaching any conclusions. 


    A common variation of this experiment is to test the effectiveness of various cleaners and sanitizers. Take a sample of an unsanitized surface. Then clean part of the surface and take another sample. Use a different cleaner on another part and take another sample. Compare the rate of bacterial growth. 

    To get a greater variety of microorganism to grow, take samples out-of-doors. Sample the soil or the water in a mud puddle. 

    Another hint: To get more use out of petri dishes, before using them, turn them over and use a Sharpie to divide the dish into quarters. Number the quarters. Now you have the equivalent of four smaller dishes. 

    This activity is suitable for school-age children and older. 

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  • 04 of 09

    Fool the Eye With a 3-D Optical Illusion

    optical illusion to create with grandchildren
    Some home science experiments can involve art supplies instead of test tubes and beakers. S. Adcox

    Optical illusions are universally fascinating, but few people understand the science behind them. Here's a chance to combine an art and science in a way that equals learning. 

    What to Do

    Gather drawing paper, markers and a pencil. Help the grandchildren trace their hands and wrists in pencil on the paper. Starting at the bottom of the paper and using a marker, have them draw a straight line until they come to the pencil outline. At that point the line should curve or "hump" to create...MORE the illusion of the hand. Continue making lines in alternating colors until the whole paper is covered and the illusion of a 3-D hand is created. Erase the pencil outline.

    Science to Learn

    Explaining 3-D optical illusions is difficult. Here's a simple explanation for young children. (For older grandchildren, you might want to research the topic together.) Things that are flat or almost flat are called 2-D, or two-dimensional. Things that are not flat are called 3-D, or three-dimensional. The human brain remembers all the things that it has seen so that it can recognize them again. When the brain looks at this artwork, it perceives not a flat piece of paper that is two-dimensional but a 3-D human hand, because of the many hands it has seen in the past.

    When the brain sees something that isn't really there, it is commonly called an optical illusion. A better term is visual illusion, because optical suggests that the deception occurs in the eye, when it really occurs in the brain.

    Practical Matters

    This project requires some patience. It's not well-suited for most children under the age of 10 or so. It's also not easy to explain. It probably works best if you do your own hand along with the kids so they can see how to do it. We used a ruler for the straight portions of the line.


    The grandchildren may be familiar with 3-D movies or even 3-D TV, but chances are that they have little idea about how 3-D works. Do a computer search and show them some of the cool 3-D street art that is currently being done. If your grandchildren are a little older, try searching for a collection of optical illusions, along with explanations of the effects. Be aware that some people can't see some visual illusions. Explain this variation so that your grandchild does not feel inadequate if he or see doesn't perceive some effects.

    This activity is suitable for grandchildren who are tweens or older.

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  • 05 of 09

    Blow Up a Bar of Ivory Soap

    ivory soap explosion experiment to do with grandchildren
    Ivory soap doesn't actually explode in the microwave, but it does expand to a great size. S. Adcox

    This experiment has one of the biggest "wow" factors ever, but it can also be used to teach the difference between a physical change and a chemical change.

    What to Do

    This experiment is about as simple as it comes. Buy a bar of Ivory soap. Unwrap it, put it on a large paper towel and put it in the microwave. Get the grandkids situated so that they can see what will happen inside the microwave. Microwave the soap for about two minutes. It will turn into a large mound of foam, about six...MORE times the size of the original bar, a process that never fails to bring exclamations of surprise and delight.

    Science to Learn

    Ivory is made differently than most soaps. Air is whipped into it. (Grandparents will remember the classic tagline, "It floats!") When you microwave it, two things happen. The soap softens, and the air that has been whipped into the soap expands. This is an example of a physical change, as opposed to a chemical change. Nothing is chemically altered, and the soap is quite safe to use, although messy. This is also a demonstration of Charles' Law, which says that as the temperature of a gas (the trapped air) increases, so does its volume (the space it occupies). The soap also contains water, which turns into steam as it is heated and also expands.

    Practical Matters

    Don't let the grandkids touch the soap for a minute or so. It will be somewhat hot. The heat also intensifies the smell of the soap, and it will linger in the microwave for a bit. It's also likely that the soap won't stay completely on the paper towel, and you will have a few bits of soap to clean out of your microwave. You can avoid this by breaking the soap in two and microwaving only half. It won't be quite as spectacular, but it also won't be as messy.


    Break another bar of Ivory in two to see if you can see the air bubbles. (You did buy more than one bar, didn't you?) Show the grandkids how it floats. Compare it with another bar of soap for floating and microwave behavior. Tell the grandchildren that popcorn pops for much the same reason as the soap expands, and finish up this experience with a popcorn snack.

    What Can Go Wrong

    Not much. This experiment is about as foolproof as can be.

    This experiment is suitable for children from preschool age on up.

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  • 06 of 09

    Create Money That Won't Burn

    money doesn't burn science experiment for grandkids
    In this experiment, money shouldn't burn, but it might singe a bit. S. Adcox

    This experiment is a little more risky, so try it only with older grandchildren and with the closest of supervision. 

    What to Do

    Dip a dollar bill in a mixture of half water and half rubbing alcohol (isopropyl or ethyl alcohol). Achieving the 50-50 mixture is a bit tricky, although it doesn't have to be terribly precise. The most commonly used rubbing alcohol is only 70% alcohol. If this is the type you have, you'll need to mix it about three parts alcohol to one part water. If you have...MORE 95% alcohol, you can mix it half and half with water. Add a pinch of salt to the mixture. Next soak a dollar bill in the mixture. Let the excess drip off. Move away from the area where you have been doing this part of the experiment--very important! I recommend going out of doors for this next step.

    Hold the dollar bill with tongs and light it. It should burn for a short while and then go out. The dollar bill should not be harmed. As you get better at this trick, you can use a higher denomination bill.

    Science to Learn

    Alcohol burns, but not at a high enough temperature to evaporate the water in the dollar bill. The alcohol is all burned up before the dollar bill even gets hot. The water keeps it cool and in no danger of burning.

    Alcohol burns with a colorless flame. Salt is primarily the element sodium, which burns with a yellow flame. The salt will cause the flame to be more visible.

    What Can Go Wrong

    A lot! All experiments involving fire are dangerous. Don't try them without a fire extinguisher at hand, and emphasize to the grandchildren that they must never use fire without adult supervision. If you light the bill in the same area where you were soaking it, you risk igniting the container of alcohol or any spilled mixture. That's why I recommend getting completely out of the area.

    If you wait too long after soaking the money before lighting it, or if you didn't quite get all of the money immersed, the edges of the money could be dry enough to singe, as they did in the picture above.

    This experiment is suitable for grandchildren who are tweens or older, with close supervision.

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  • 07 of 09

    Do Magic With Light Rice

    light rice educational activity with grandkids
    Kids love magic tricks, and this science experiment disguised as a magic trick will intrigue and teach them. S. Adcox

    Do you have a grandchild who is fond of magic? This experiment combines science with the fun of a magic trick.

    What to Do

    To begin, assemble two empty, dry water bottles and two chopsticks, along with a couple of pounds of regular rice -- not instant. You can set up the bottles yourself and have the grandchildren puzzle over the results, or you can have a grandchild in on the trick.

    Fill both water bottles with rice, using a funnel or improvisiung one with a sheet of heavy paper rolled into a cone....MORE Leave one bottle alone. Label it "heavy rice." Tap the other bottle on the counter until the rice settles and you can add more rice. Do this over and over until you can't get the rice to settle any more. Label that bottle "light rice." Now it's time for the trick.

    Thrust the chopstick into the "heavy rice" first. When you pull up on the chopstick, it immediately pulls out of the rice. The rice is "too heavy" to be lifted. Then push the chopstick into the "light rice." (The trick works best if you angle the chopstick so that it is pushed against the side of the bottle.) Pull up on the chopstick, and the bottle of "light rice" should lift right off the counter. If you have a kitchen scale, use it to weigh the bottles of rice. Of course, the "light rice" will weigh more.

    What Can Go Wrong

    Test this experiment before you go "live." If the rice isn't packed sufficiently, it won't work.

    Science to Learn

    This "magic trick" works because the grains of rice are packed so densely (that word again!) that friction holds the chopstick tight. It's as if the rice grains are gripping the chopstick. If the grandchildren need a definition of friction, tell them that it is what happens when two things rub against each other.


    Another fun friction experiment is done with phone books. Take two phone books of about the same size. Place them on a counter with the spines facing out and interweave the pages of the books by flipping the pages, sort of like shuffling cards. Then have the kids try to pull the phone books apart. They shouldn't be able to do it. The many points of contact create so much friction that it takes a lot of force to overcome it. If, on the other hand, you divide the books into two or three "chunks" and interlace them, they can be easily pulled apart. For maximum difficulty, the books should be interweaved page by page, but that would take a very long time.

    This experiment is suitable for school-age grandchildren.

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  • 08 of 09

    Make Your Own Kaleidoscope

    homemade kaleidoscope to make with grandkids
    Learn about light, optics and symmetry with a homemade kaleidoscope. S. Adcox

    Do you have an empty cardboard tube on hand? All you need is something reflective to make your own kaleidoscope.

    What to Do

    Kaleidoscopes can be made from a wide variety of materials. Kits are available, but if you make your own, the grandchildren will have a learning experience as they find what works best. This is a simplified version with a single tube. The effect will be created by rotating the whole tube.

    A paper towel tube will hold the other components. The most important part of the...MORE kaleidoscope is the mirror assemblage. You can make this with real mirrors, but they are hard to work with and dangerous, being glass. Acceptable substitutes include mirror paper, which works well but is hard to find, cardboard covered with aluminum foil, which works but not really well and, believe it or not, clear report covers. Whatever material you decide upon will need to be folded into a triangular shape, taped well and slid into the paper towel tube. It should be just a little shorter than the tube. For the eyepiece end of the tube, you will need a piece of cardboard or opaque plastic. Cut an eyehole about a quarter of an inch big in the cardboard or plastic, and tape it to one end of the tube.

    Now you'll need to create your object chamber. You'll need some transparent plastic and some semi-transparent plastic. Check out any empty food containers you have saved for these supplies. Cut a circle of the transparent plastic and push it into the tube, up against the end of the mirror assemblage. Find some small beads, crystals and other small objects. Put them in the end of the tube and seal with a disc of the semi-transparent material. If the last disk won't stay in by itself, you can fasten it with some tape, but tape it lightly so that you can experiment with putting different materials in.

    When your kaleidoscope is finished, point it toward a light source and rotate it slowly to see the shifting patterns.

    What Can Go Wrong

    This is a rudimentary kaleidoscope, and it's not easy to work with the object chamber.

    Science to Learn

    Not all kaleidoscopes have three mirrored surfaces. Some have only two mirrors. Those will produce 6 to 8 images depending upon the angle of viewing. Three-mirror systems produce an infinite number of images, although how many are actually seen are dependent on such variations as the quality of the materials used. Because the images are created by reflection, they are symmetrical.


    It's great fun to experiment with different objects. Our most stunning images included a scrap of an orange sack. Trying making all-natural kaleidoscopes with leaves, seeds and flower parts.

    When you were creating the kaleidoscope, did you look through the mirrored tube? At that point, you had created a teleidoscope, used to create multiple images of whatever you are looking at. 

    You'll also want to tell your grands about the world's largest kaleidoscope.

    This craft is suitable for school-age grandchildren.

    Need more educational activities? Check out these nature activities.

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  • 09 of 09

    Get It Delivered

    Grandson ready for another science project
    Kits that you can buy by mail will keep your little scientist engaged. Ableimages / Getty Images

    If you want to share the fun of science with your grandchildren in an easier way, consider ready-made science kits. These can be ordered whenever you like, or you can use a subscription service that will send a kit every month. 

    Most of these kits don't use the term science but instead use the descriptor STEM (science, technology, engineering and math).

    Science Kit Subscriptions

    The idea of kids' kits by mail has taken off in recent months, and some of these sites are quite new. Do some...MORE research before you sign up. It's always a good idea to search for reviews, check start-up dates and read press coverage. 

    Spangler Science Club: Steve Spangler has the gift of making science fun for kids. You can order a monthly STEM kit designed for ages 7-14. Choose from three price structures. The top level is designated as more complex projects that are designed for children and adults to work on together. Cost ranges from $15 to $30. Steve Spangler Science is also a great place to order other science kits and miscellaneous supplies.

    Tinker Crate: A spin-off of the popular Kiwi Crate subscription service, Tinker Crate is aimed at children 9-16. In addition to each month's project, a magazine with additional activities is included in each month's box.

    The Young Scientists' Club: Affiliated with the Magic School Bus, this company offers kits that can be shipped once or twice monthly, targeting kids ages 5-12. Cost per kit is $11.99 plus shipping. This site also offers an array of kits with the Clifford the Big Red Dog branding. These are suitable for kids 3 and up and are available for ordering but not as a subscription service. Many kits are also available for purchase in stores or by mail. See my review of this company's Jumping Into Electricity Kit. 

    Genius Box: Aimed at kids 8-11, a Genius Box subscription runs $23-25 per month. Shipping is free. Each month's box contains at least three activities to be completed with minimal help from adults.

    Green Kid Crafts: This company uses the acronym STEAM instead of STEM, adding in an arts component and with an emphasis on the environment. Their Discovery Boxes ship monthly for a cost that ranges from $17.95 to $19.95 per month, plus shipping. Designed for children 3-10, each box contains multiple activities with eco-friendly components.

    Blue Moon Box: Designed for kids 6-12, each month's box contains 2 or 3 experiments with supporting materials.