Make a super-cool spinning toy using skateboard bearings, super glue and a little physics. Customize your design with a marker tie-dyed shoelace.
Warning: Not for recommended for kids under 5. Use adult supervision for super glue, sharp points, rubbing alcohol and glue gun.
-4 skateboard bearings (available online or at skateboard stores)
-superglue or Krazy Glue
-a white shoelace
-permanent markers, like Sharpies
-rubbing alcohol (isopropanol)
-a glue gun
1. Use a sharp point to remove the cover from one of the bearings so that you can see the ball bearings inside. (See image above.)
2. Cut a piece of paper 6cm x 6cm and draw an X from corner to corner.
3. Center the bearing with the cover removed in the middle of the X. Then, center the other 3 bearings around the one in the middle so that they’re evenly spaced. You can use a ruler to check spacing. (See image below.)
4. Add a single drop of super glue to the junction between each bearing to connect them. If you add too much, the spinner will stick to the paper. *Be careful not to get any glue onto the moving parts of the bearings.
5. When the glue is dry, carefully turn the spinner over and place another drop of glue at each junction.
6. When the glue is dry, prop the spinner up on its side and add glue to the junctions on the sides. (See image below.) Repeat on each side.
7. While the spinner glue is drying, make dots of permanent marker on the shoelace. In a well-ventilated area, suspend the shoelace over a tray or colander and drip rubbing alcohol onto it to make the colors run together. (See image.) Let it dry completely.
8. Use the glue gun to attach the shoelace to the outside edges of the spinner. Fill in gaps between the lace and bearings with hot glue.
9. Spin away!
The Science Behind the Fun:
If you look closely at a skateboard bearing there are only a few ball bearings connecting the center and the outside part that spins. This means that there’s very little friction, or rubbing, between the parts. If you spin the toy around the center bearing, that bearing is called the axis of rotation.
The three bearings on the outside of the spinner provide the rotating mass that gives the toy a property called angular momentum, which keeps it spinning until the frictional force from the ball bearings in the center slows it down.
Pigments are molecules that give things color. The pigments in permanent markers are trapped in ink compounds that are insoluable in water, which means that they won’t dissolve in water. However, if you add a solvent, like rubbing alcohol, or isopropanol, to permanent markers, it dissolves the ink. As the alcohol moves through the cloth you are decorating, it carries the pigments along with it.
This fun project from my book Outdoor Science Lab for Kids shows you how to collect and identify amazing arthropods using a net you make yourself. For more engaging outdoor experiments, you can order the book here, or anywhere else books are sold.
– sweep net or: two wire hangers, an old, light-colored pillowcase, scissors, pliers, long wooden broomstick or sturdy yardstick, and duct tape
– area with long grass
-large white piece of fabric, like an old sheet
– insect identification books (optional)
Safety Tips and Hints
- Don’t pick insects up with your bare hands, unless you know they don’t bite or sting.
- Ticks love tall grass. If there are ticks in your area, take precautions and do a tick check after your insects hunt.
Step 1: If you don’t have a sweep net, make one by straightening and twisting two wire hangers together. Form them into a loop, leaving about 3 inches (8cm) straight on either end. Cut about one third off of the open end of a pillow case and pull the mouth of the pillowcase over the wire loop. Tape it securely around the perimenter.
Step 2. Find an area with long grass and plants. Sweep with your net the same way you’d sweep a floor, but flip the open side of the net back and forth to capture insects in the grass.
Step 3. Close your net by flipping the bottom over the top and take it over to your large piece of fabric.
Step 4. Carefully dump the creatures you’ve collected onto the white fabric to inspect them. If you want a closer look, put an insect inside a jar with a loose lid.
Step 5. Count how many legs they have, how many body segments, look for antennae, wings and unique color. Record your observations in a notebook.
Step 6. Use insect identification books, or other means to identify what you’ve found.
Step 7. Keep a journal of the insects and arachnids you capture, the time of day, and where you found them.
The Science Behind the Fun:
When you sweep, chances are you’ll find lots of insects, which are arthropods with six legs. They often have wings, and their life cycle goes from egg to larva, to adult. Some insects, like butterflies, also go through a pupal stage, in which their bodies are significantly transformed. The antennae on their heads are sensory organs.
Tillandsia, also known as Air Plants, come in many shapes, sizes and colors. In nature, you’ll find them living in trees in warm places like South America. They collect moisture from the air and rain, rather than pulling it up via roots like most plants, so you can care for them with a weekly misting.
Pick up a few clear, hollow “decorate your own” ornaments, and you can use these living wonders to make unique homemade decorations. We’re giving them as gifts this year.
-clear ornaments with removable tops
-small Tillandsia that will fit through ornament tops (Air Plants are available at most nurseries. Ask for care instructions, if they have them.)
-needle nose pliars, or tweezers
Note: Choose plants that are small enough to fit through the openings of your ornament!
Mist your plants, or soak them in a bowl of clean water for 15 minutes or so, gently shake off the excess water, and carefully push them into the ornaments, bottom first so you don’t harm the plant. Put the top back on the ornament, leaving it loose enough for air to circulate.
Once a week or so, remove the top of the ornament and add some water. Coat the entire plant with water, pour out the excess and put the top back on. After the holidays, you can remove the plants with tweezers and move them to a new home in a vase, bowl or other clear container.
Buying gifts is fine, but it’s more fun to make them. This year, we decided to make botanical gifts for the adults on our list, and slime kits for the kids.
To make a slime kit, you’ll need:
-glitter glue (optional)
-Borax laundry detergent
-small plastic sample cups or paper cups (optional)
-jars with lids
-a small plastic bin or shoe box
-extra glitter (optional)
Label the jars and fill as follows:
- Bouncy Ball Mix (fill with glue)
- Slime Mix (fill with equal parts glue and water, mixed well)
- Borax detergent (fill with powdered detergent)
- Cross-Linking Solution (leave empty)
- optional-Sparkly Bouncy Ball mix (fill with glitter glue)
- optional-Sparkly Slime Mix (fill with equal parts water and glitter glue, mixed well)
Make an instruction sheet for the kit. (Print out the info below, or copy it onto a card.)
To make slime:
- Fill Cross-Linking Solution container with warm water. Add about 2 tsp Borax per 1/2 cup water to the container. Mix well. (Don’t worry if all the Borax doesn’t dissolve!)
- Add a few spoonfuls of Ball Mix or Slime Mix to a small plastic cup or paper cup.
- Add a drop or two of food coloring to the cup. Stir.
- Add 3 spoonfuls of the Cross-Linking Solution to your ball mix or slime mix and stir well.
- If the slime still feels too sticky, add a little more Cross-Linking Solution.
- Remove your completed slime from the cup.
The Science Behind the Fun:
Glue is a polymer, which is a long chain of molecules linked together, like a chemical chain. The polymer formed by water and glue is called polyvinyl acetate.
The Borax solution is called a cross-linking substance, and it makes the glue polymer chains stick to each other. Eventually, all the chains are bound together and no more cross-linking solution can be taken up.
To finish the slime kit, fill the plastic bin with the ingredients you put together, including jars of ingredients, instructions, plastic spoons, and mixing cups (optional.)
There are few gifts that are more fun (and less expensive) than a homemade science kit. Give a kid a bottle of vinegar and a box of baking soda and you’ll make their day. Throw in a bottle of Diet Coke and some Mentos mints, and you may be their favorite person ever. Make a kit for your kids or grand kids. Make one for your favorite niece or nephew. Encourage kids to make kits for friends and siblings. Make one for yourself!
When kids do science at home, there are no rules, there are no time limits, and no one is judging their results. It’s the perfect opportunity for them to explore, make guesses about what will happen and try new things. In other words, they’re learning to be creative. What could be better than that?
Below are some ideas for great items to include in your kit. I’ve highlighted links to the experiments on my website (just click on the blue experiment name) in case you want to print out directions to add to your kit.
You can also find these experiments, and more, in my book Kitchen Science Lab for Kids (available wherever books are sold online and in stores), on my free KidScience app for iPhones/iPads/iPods and on my Kitchen Pantry Scientist YouTube channel!
composition book: Makes a great science notebook to draw, record, and tape photos of experiments into.
clear plastic cups to use as test tubes and beakers
measuring spoons and cups
school glue for making Mad Scientist’s Green Slime
Borax detergent to use as a cross-linker for the Green Slime
gummy worms to transform into Frankenworms
baking soda: Can be used for a number of experiments like fizzy balloons and magic potion. Mix with vinegar to make carbon dioxide bubbles.
vinegar Great for fizzy balloons , alien monster eggs and magic potion.
balloons for fizzy balloons
dry yeast for yeast experiment
white coffee filters: can be used for magic marker chromatography, in place of a paper bag for a coffee-filter volcano or making red cabbage litmus paper.
cornstarch:Lets you play with Cornstarch Goo, a non-newtonian fluid. Here’s the video.
marshmallows with rubber bands and prescription bottle rings you have around the house can be used to make marshmallow catapults. My kids used theirs to make their own Angry Birds game.
Knox gelatin and beef bouillon cubes can be used to make petri plates for culturing microbes from around the house. You can also use the gelatin for cool osmosis experiments!
Food coloring Helps you learn about surface tension by making Tie Dye Milk. Here’s the video. You can also easily make colorful sugar-water gradients that illustrate liquid density!
Mentos mints will make a Mentos geyser when combined with a 2L bottle of Diet Coke.
drinking straws are great for NASA soda straw rockets and a carbon dioxide experiment.
Today on WCCO MidMorning, I’ll be talking microbiology! According to the CDC, hand washing is the best way to remove microbes from your hands.
You can see what bacteria and fungi are hanging out on your fingertips by touching homemade petri plates to grow colonies. Test your fingers before and after washing with water alone, soap and water, and finally hand sanitizer. You can find the experiment in my book, Kitchen Science Lab for Kids, and here on my website. The video below shows you how to make plates.
My 9 YO and I did some fun experimenting yesterday to figure out the best way to make bath bombs. As a starting point, we tried a few recipes off of the internet. The first was was crumbly and smelled too strongly of olive oil, and the next one was equally tricky to work with. After our first two failures, we looked at our results and decided to omit the water in the recipes, using just coconut oil to hold the mix together. It worked well! Here’s the recipe we came up with. You may have to tweak it a little by adding a tiny bit more oil to make the perfect bath bomb mixture!
1 cup baking soda
¼ cup cream of tartar
2 Tbs. coconut oil, melted to liquid
empty contact lens case
-Whisk together baking soda and cream of tartar. Slowly drizzle in coconut oil, mixing immediately. Stir for several minutes until you get a nice even mixture that holds together when you press it between your fingers.
-Separate the mix into 3 or 4 bowls, and add a few drops of food coloring to each bowl. Mix again until color is incorporated.
-Press the bath bomb mixture into empty contact lens cases and gently tap the backs with a spoon to remove fizz tablets. It may take a few tries to get the hang of it! If they don’t stick together, try adding a little more oil and mixing again. Dry the bath fizzies on a plate or cooking sheet and package in cellophane bags or pretty baking cups for friends and family. Use your fizz bombs within a few weeks for maximum fizziness!
–Older kids can make larger “bath bombs” using molds for round ice cubes (which we found at Target.) Double or triple the recipes, gently press some mixture into each side of the mold, and mound a little extra on each side. Press the mold together to compress the bath bomb mixture into a single ball. Tap one side gently with the back of a spoon and gently open the mold to release that side of the sphere. Hold it in your palm and repeat with the other side to release the entire bath bomb from the mold.
The science behind the fun: The chemical name for baking soda is sodium bicarbonate, and cream of tartar is potassium bitartrate, or potassium hydrogen tartrate. When you mix them together in water, you create a chemical reaction that forms carbon dioxide gas bubbles! It’s interesting to note that at temperatures below 76 degrees F (25 C), coconut oil is a solid, but that at temperatures above this, it melts into a clear liquid. How does this affect your bath fizzies? Will they work in cold water as well as they do in warm water? Try it!
I’ve been having fun with fermentation the last few weeks and my kids loved making root beer. In a week or two, I’ll post instructions, but here’s a general how-to demo I did on WCCO MidMorning.
My 8-YO loves Orbeez, those water-thirsty polymer balls that go from the size of cookie sprinkles to the size of marbles after a quick soak.
I wondered whether we could make something similar from gelatin or agar.
A quick search online showed me that some chefs use a technique called oil spherification to make tiny round morsels using everything from balsamic vinegar to fruit juice, mixed with gelatin and agar. It’s known to cooks as a “molecular gastronomy” technique, and takes advantage of the fact that water and oil don’t mix. Water-based droplets falling through chilled oil form into perfect spheres due to surface tension, and gelatin and agar added to the mix are colloids that solidify as they cool.
We made some fun (inedible) orbs of our own, using the technique: standard orbs (from gelatin or agar and water), floating orbs (with agar and vinegar) and color-changing acid/base indicator orbs (from red cabbage juice and gelatin or agar.) Adult supervision is required for this project, since it involves hot liquids. The orbs may also be a choking hazard, so keep them away from toddlers. I demonstrated how to make them on Kare11 Sunrise News.
To make magic orbs, you’ll need
-unflavored gelatin or agar*
-cold vegetable oil in a tall container. Chill oil in freezer or on ice for at least an hour, or until it is cloudy, but still liquid.
HINT: Orbs made with vinegar and agar shrink better than those made with gelatin (see floating orb recipe below!)
Standard colored orbs:
1. With adult supervision, dissolve 5 packets unflavored gelatin or 2 Tbs. agar in 1 cup hot water. Add 2 tsp. vinegar. Microwave and stir until completely dissolved.
2. Pour into smaller containers and add food coloring. When cooler, but not solid, add the melted, colored gelatin or agar to an empty glue container or squeeze bottle.
3. Drip gelatin or agar solution into the cold oil, a few drops at a time so it forms into marble-sized orbs and sinks. Drip two colors together to make multi-colored orbs! Allow to cool for 30 seconds or so and retrieve with a slotted spoon or strainer. Rinse with water and repeat, re-chilling the oil as needed until you have as many orbs as you want.
4. Rinse orbs with water. Dry them out by setting them on a plate overnight if you want to see them shrink and then re-hydrate them with water. Orbs can be kept in a plastic bag in the refrigerator. (Keep away from small children, since they may be a choking hazard.)
To make floating orbs, follow directions above, but make with 1 cup white vinegar and 2 Tbs. agar. They will sink and float when added to water with a few tsp. of baking soda mixed in as the vinegar and baking soda react to form carbon dioxide gas.
To make color-changing orbs, dissolve 2 Tbs. agar or 5 packs unflavored gelatin in 1 cup red cabbage juice (magic potion) and follow directions for making orbs. Then drop them in vinegar to watch them turn pink or in water containing baking soda to watch them turn blue!
Could you make homemade jelly beans using flavored gelatin using this same method? Try it!
*Agar, or agar agar flakes can be found in the Asian food section of many grocery stores!
Microbes are always fighting for space.
Bacteria and fungi try to outnumber other tiny competitors using chemical warfare, among other things. That’s why many antibiotics (which kill certain bacteria) are actually produced by other bacteria. One reason foods like yogurt and cheese, which are made by beneficial bacteria like Lactobacillus acidopholis, don’t easily spoil is that these bacteria can turn milk sugars into lactic acid. This makes their environment toxic to some of their competitors, like pathogenic bacteria. Luckily, we humans aren’t harmed by lactic acid and can enjoy its tangy flavor.
To grow bacteria in labs, scientists have to take care of them the way you’d take care of a pet. You have to give them the type of food they like, the right amount of oxygen and moisture, and keep them at their optimal temperature.
The same principles apply to growing the bacteria that make yogurt. You prepare the bacteria’s food by heating some milk and letting it cool to a temperature that the bacteria can tolerate. Then, you add the bacteria and let them grow for about eight hours. During that time, the bacteria will happily divide, multiply and eat milk sugar. In the process, they’ll produce lots of lactic acid which changes the way the proteins and fats in the milk interact, forming a more solid food product.
We made yogurt in our crock pot, which turned out to be a lovely bacterial incubator. The end product was a little runny, but putting it through cheese cloth (or a coffee filter in a plastic bag with the tip cut off) gives you thicker yogurt. It is delicious! Here’s how we made it, thanks to directions from Stephanie O’Dea:
Ingredients: 8 cups (half-gallon) of whole milk , 1/2 cup grocery store yogurt (must contain live/active culture), thick bath towel, slow cooker
Turn crock pot on to low. Add an entire half gallon of milk. Cover and cook for 2 hours and 30 minute. Unplug your crock pot, but leave the cover on. Let it sit for 3 hours so your bacteria will not be overheated when you add them.
After 3 hours, put 2 cups of your warm milk in a bowl. Whisk in 1/2 cup of the live/active culture yogurt. Dump the bowl contents back into the crock pot and stir well. Wrap a heavy bath towel all the way around the unplugged crock pot as insulation and let your bacteria grow for 4-8 hours or until thickened. Refrigerate and enjoy with fruit, honey, or granola. As I mentioned, you can strain the yogurt if you prefer a thicker consistency, and your homemade yogurt will make a great starter culture for the next batch!
Happy kitchen microbiology!