Repost from Dec.19th, 2010 (Photos from Kitchen Science Lab for Kids, Quarry Books 2014)
Have you ever gotten a shock from a doorknob after shuffling across a carpet? The term “static electricity” refers to the build-up of a positive or negative electrical charge on the surface of an object. In this case, the charged object is your body. You feel an electric shock as the charge you’ve collected from the carpet jumps from your hand to the metal doorknob.
Tiny particles called electrons have negative charges and can jump from object to object. When you rub a balloon on your hair, or a comb through it, many of these electrons are stripped from your hair and move to the balloon or comb giving it a negative charge (and often leaving your hair all positively charged and standing up as the strands try to avoid each other.)
The negatively charged balloon or comb then makes a great tool for making electrons jump around!
You can easily make a contraption called an electroscope using:
-some thin aluminum foil or mylar (the shiny stuff balloons and candy wrappers are made from)
-a balloon or comb.
- Cut the cardboard to fit over the mouth of the jar, poke the nail through the cardboard, tape on two long, thin strips of foil or mylar (see photo) and place the whole thing in the jar so the foil strips hang down, touching each other.
2. Charge your balloon or comb by rubbing it on your hair or clothing to give it a negative charge. Bring the charged object close to the nail head. You don’t even have to touch it!
What happened? Some negatively-charged electrons jump from the comb to the nail and into the strips of foil. The negative charge on the comb will push electrons (which are also negatively charged) down to the foil/mylar and give both strips a negative charge. The two strips try to move away from one another as the like charges repelled each other.
What happens when you make the strips out of different materials like paper? Are there other charged objects you can use to make your foil strips “dance”?
You can also bend a thin stream of water from the faucet by holding your charged comb next to it. The water is uncharged and is pulled toward the negative charge of the comb.
Try making small pieces of tissue paper float or dance by holding a charged comb or balloon next to them! We filled an empty soda bottle with tiny pieces of foil and made them jump around with a charged comb held close to the bottle.
(Re-post from April 14, 2016)
I love traditional tie-dye, but it’s fun to do this experiment that uses permanent markers and rubbing alcohol to make bright, gorgeous designs that mimic tie-dye, more easily, and with less mess.
This experiment was created by Bob Becker, a chemistry and AP chemistry teacher at Kirkwood High School in Kirkwood, MO. (To find a few of the original experiments I invented, check out Frankenworms, Sugar Cube Fizz Bombs, Homemade Window Stickies, Foaming Slime, and Cornstarch Frescos.)
Here’s a video from my YouTube channel on how to do this experiment, so kids can “watch and do.”
To play with permanent marker tie dye, you’ll need:
-permanent markers (like Sharpies)
-cotton items to decorate, like tee-shirts, socks, or dish towels
-rubbing alcohol (isopropanol)*Read warning labels. Parental supervision is required, since rubbing alcohol is poisonous if swallowed. Do this experiment in a well-ventilated area, and do not expose your artwork to heat until is is COMPLETELY dry, since rubbing alcohol and its fumes are flammable.
-containers like plastic cups or jars
To make your designs, stretch the cotton over the mouth of a jar or cup and secure it with rubber bands. (See video above.)
Use permanent markers to make several dime-sized dots of different colors on the stretched cotton.
Slowly drip rubbing alcohol onto the spots of color until the alcohol starts to soak outward, carrying the ink with it.
Allow your design to dry overnight. When completely dry, hang your shirt in the sun, or put it in the dryer for 15 minutes to set the color. Wash separately from other clothes, just in case!
The Science Behind the Fun: 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. Small pigment molecules move faster than big ones, so the colors sometimes separate into their different color components as they move through the cloth. The alcohol evaporates into the air, leaving the ink in the fabric, and since it is still insoluable in water, it won’t come out when you wash it.
Enrichment: What happens if you draw lines, concentric circles or different shapes on your designs? Can you layer colors and watch them separate? What if you add rubbing alcohol next to the color, instead of directly on it? How many drops of alcohol do you have to add to a dime-sized color spot before it starts to expand?
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.)
Here are ten quick and easy experiments to make your Halloween even more fun and memorable!
Click on these links for instructions on how to make:
Here are a few of my favorites!
You can find more experiments by scrolling down on my website!
If you’ve ever seen the X-Files, you know that foaming green alien blood is pretty scary.
It’s simple to use kitchen table chemistry to mix up your own batch of green alien blood with corn syrup, green food coloring, water and baking soda.
Just add vinegar (tell your friends it’s water) to make it foam.
2 Tbs corn syrup
1 tsp baking soda
green food coloring
1/2 tsp water
When you want to make your slime foam, add a few tsp of vinegar.
You could make the same thing with red food coloring and call it vampire blood!
The Science Behind the Fun: When you add baking soda (sodium bicarbonate) to vinegar (acetic acid), there’s a chemical reaction that creates carbon dioxide gas bubbles!
Experiment created by Liz Heinecke at KitchenPantryScientist.com
You’ll need 8 oz water bottles, glue, Borax detergent, baking soda and vinegar.
First, decorate full 8 oz water bottles with tape, marbles and whatever else you can find.
Then, follow these directions to make foaming slime ooze out of their heads, using a simple chemical reaction! You’ll love it!
I’ve always wanted to try paper marbling and knew there must be some science involved. So, we gave it a go, and the results were stunning!
We tried two methods: one with liquid starch (made from cornstarch) and tempera paint, and another with a marbling kit. Both worked well, but look very different.
The Science Behind the Fun: Water molecules like to stick together, a property which scientists call surface tension. This property allows very thin layers of ink to float on water, mixing in beautiful patterns when you break the surface tension with detergent, a tool like a paintbrush, or movement. To marble paper, you have to use dye or paint that floats on the water where it can be easily transferred to paper. Alternately, you can make the liquid underneath more dense than the dye or paint, to help the dye float.
When transferring the ink or paint designs, it helps to use paper that’s been coated with a chemical called a mordant, that combines with substances (usually dyes) to make large molecules that stay in one place. (Iodine is another mordant, which is used to stain bacteria.)
Here’s a video of my 10YO making designs using the pre-made marbling kit…(More info at the bottom of this post.)
Since I like to do experiments using non-toxic, inexpensive ingredients most people have on hand, we first tried a method that uses cornstarch to thicken the bottom liquid layer and tempera paint as the dye. It requires pre-treatment of paper, like inexpensive watercolor paper from Target, with the mordant aluminum sulfate (alum), which you can find at your local coop or grocery store.
-watercolor paper (cheap stuff from Target works just fine)
-two large, flat trays, like 9×13 pans
-2 tps. Alum (aluminum sulfate crystals)
-a sponge brush
-2 Tbs. corn starch
-tempura paint (the more colors, the merrier)
- Dissolve 2 tsp alum in 3/4 cup water. Avoid inhaling powder.
- Mark one side of your watercolor paper with an A and use a sponge brush to apply alum solution evenly to that side of the paper.
- Let the paper dry overnight, or speed drying with a blow dryer.
- Make a double recipe of liquid starch by dissolving 4 Tbs. corn starch in 1/2 cup cold water. Bring 6 cups water to a boil in a sauce pan. Add the cornstarch solution to the water, stir well and boil for 1 minute. Turn the heat to low and simmer for 2 more minutes, stirring occasionally.
- Pour 3 cups of the hot liquid starch into one 9×13 pan and let cool.
- Pour 3 cups of cold water into the other pan.
- Prepare paint by mixing tempura paint with water until it has the consistency of half-and-half or whole milk.
- When starch is cool, drip paint onto the surface of the starch using an eyedropper, or something similar. Rinse dropper between colors.
- Swirl paint, or use toothpicks to drag out patterns.
- Carefully place your paper on the paint, alum side-down. Let it sit for a minute or two.
- Carefully peel the paper off of the paint and gently place it, face up, in the water pan. Let it sink and move it back an forth gently to rinse off excess paint.
- Set the paper on a piece of newspaper to dry.
- Make more marble paper in the same paint pan. When you’re ready, repeat using the rest of the cornstarch.
The Innovation marbling kit (Boku-Undo Suminagashi) from DickBlick.com pictured below includes pre-made low density dyes that you drip onto a tiny floating disc of paper in a tray of water. It’s tons of fun and yields beautiful results. I got the kit at Blick art supplies, and used the paper they recommended, which may have been pre-treated with a mordant.
I learned how to make this fun, clay-based paint at the Minnesota State Fair’s Eco Experience Progress Center. It’s colored with natural pigments(pigments are molecules that give things color) and doesn’t give off the same chemical fumes as some of the paints you might find in a hardware store. I love the earthy colors you can mix up with elemental pigments like iron oxide, zinc oxide and black iron oxide. It’s fun to mix up a little blue too, using Ultramarine Blue dried pigments.
To make this paint, you’ll need:
EPK powdered clay (also called EPK Kaolin) -Can be ordered online. We got ours at continentalclay.com.
dried pigments, like the ones I mention above. -We got ours at dickblick.com
Safety tips: Check the warnings on dried pigments before you purchase them. Some are toxic and must be handled carefully. Avoid inhaling pigments.
To make your paint:
1. In a bowl, stir together 1/2 cup flour and 1/2 cup cold water. Mix well.
2. Add 1/4 cup hot water and mix well.
3. Add 1/4 cup EPK powdered clay and stir until smooth.
4. Continue adding flour and water until the paint has the consistency you want.
5. Divide the paint into several containers and mix in pigment for color.
6. Use paint on paper or canvas.
7. Paint may be stored in the refrigerator for a week or so.
Our eight Monarch caterpillars were in chrysalises when we returned from our vacation, and yesterday the first of them emerged! We were lucky enough to catch it on our iPhone time-lapse, which makes everything look faster than it actually happens. You’ll be amazed at how the butterfly pumps fluid from its body to expand its beautiful orange and black wings.
Our neighbor brought us some Monarch Caterpillars the other day, and we found a tiny one in our garden. They’re now happily munching away on milkweed on our screened-in porch, safe from birds!
Here’s a short video on how to find and raise caterpillars, via my new book, Outdoor Science Lab for Kids.