This morning, on Kare11 Sunrise, I showed off my new book, Kitchen Science Lab for Kids, and demonstrated three experiments from the book. Just click on the experiment name for directions, photos and more about the science!
Frankenworms- Bring gummy worms to “life” using a chemical reaction.
Magic Bags- Explore the elastic properties of polymers.
Leaf Chromatography- Separate plant pigments on coffee filters.
This is especially fun in the fall, when you can compare green leaves to red and yellow ones! Here’s a nice article on the chemistry of the colors of fall leaves (from the Compound Interest website) that my friend Joanne Manaster highlighted on her Joanne Loves Science Facebook page.
-a glass bottle, like a juice bottle, whose neck is a little smaller than a hard-boiled egg
-small or medium-sized hard-boiled eggs, peeled
-a long match or lighter
1. Decorate your bottle to look like a monster, with the mouth of the bottle on the mouth-end of the monster
2. Put one or two birthday candles in the wide end of a hard-boiled egg.
3. Light the candles and hold them under the inverted bottle to warm the air inside.
4. Hold your bottle upside down and put the candle end of the egg up into the bottle so it forms a seal. Continue to hold the egg until the candle goes out and the egg is “pushed” into the bottle by atmospheric pressure, which is the weight of the air pushing down on the egg.
The flame from the candle heats the air in the bottle. When the candle goes out from lack of oxygen, the remaining air in the bottle cools rapidly, decreasing the air pressure in the bottle and creating a partial vacuum. The outside air, whose atmospheric pressure is higher, pushes the egg into the bottle as it attempts to equalize the pressure inside of the bottle.
If you start today, you can grow gorgeously gruesome rock candy, dripping with sugary fake blood, in time for Halloween. (It takes a week or two to grow nice big crystals.)
This experiment requires adult supervision for boiling and handling the hot sugar syrup. Once it’s cooled down, kids can take over.
To make 12-15 sticks, you’ll need the following:
-2 and 1/2 cups white granulated sugar
- 1 cup water
-cake pop sticks or wooden skewers
-red food coloring
- Dip one end of cake-pop sticks or wooden skewers in water and then roll them in granulated white sugar. The sugar should cover 2-3 inches of the stick. Let them dry completely. These are the seeds for the sugar crystal growth.
- Boil 2 cups water and 5 cups sugar until sugar is dissolved as much as possible. It should look like syrup. Once it cools, this syrup is your supersaturated sugar solution.
- Let syrup sit until it is no longer hot and pour into a large glass jar or deep bowl.
- When syrup is completely cool, set the sugary end of the sugar-seeded cake pops or skewers into the syrup, evenly spaced in the jar. Cover loosely with plastic wrap and let them sit for about a week. Gently move the sticks around occasionally, so they don’t stick to each other and the crystals in the bottom of the glass. If the glass container gets too full of crystals, pour the syrup into a new container and move your stick into the cleaner syrup to grow more crystals.
- When the rock candy is done, pull them from the syrup and let them dry. Save the syrup.
- To serve, pour a few cm of your sugar syrup into the bottom of a pretty glass and add a few drops of red food coloring. Stir.
- Put your rock candy, handle side up, into the glass. Be sure to give your guests napkins, so they don’t drip “blood” all over the house!
How do Crystal Grow?
Like bricks in a wall, crystals are solids formed by a network of repeating patterns of molecules. Instead of the mortar that holds brick together, the atoms and molecules are connected by atomic bonds.
Crystals that share the same chemical composition can be big or small, but the molecules always come together to form the same shape. Table sugar, or sucrose, is made up of a molecule composed of two sugars, glucose and fructose. Crystals formed by sucrose are hexagonal (six-sided) prisms, slanted at the ends.
The crystals on your rock candy sticks grow from the “seeds” of the sugar you rolled on the stick before you put them in the syrup.
Plants love water as much as vampires love blood. Although they don’t have long thin fangs, they’ve developed a great system for pulling water up through their trunks and stems to their highest leaves using capillary action.
The kids and I demonstrated how to make them on Kare11 Sunrise news last week. Click here to watch.
Make a vegetable vampire and watch capillary action move colored water through the cabbage creature you created.
To make a leafy vampire, you’ll need:
-head of fresh napa cabbage
-2 large cups, jars or plasticware containers large enough to hold the base of ½ of your cabbage
-fruits and veggies to use as eyes and eyebrows on your monster
-rubber bands or string
First, fill your two containers ¾ of the way to the top with warm (not hot) water.
Add 10 or more drops of blue food coloring to one container and 10 or more drops of red food coloring to the other .
With a sharp knife, cut the cabbage in half vertically, from the bottom up, leaving the top 10cm or so intact, so the two pieces are still attached at the crown. If possible, try to cut down the middle of one of the big leaves.
Use rubber bands to secure the bottoms of each side of the cabbage and make a fresh cut at the bottom, a few cm up from the old cut.
Put one half of the base of your cabbage in the red water, and the other half in the blue water.
Decorate your two “vampires” with eyes and spooky eyebrows made from olives and peppers (or whatever you have in the refrigerator.) Secure the decorations with toothpick.
Keep an eye on your cabbage to see how much colored water it’s drinking. Your vegetable vampire will have to drink for 24-48 hours for the best results.
Plants survive by drawing nutrients dissolved in water up into their stems, stalks, trunks, branches and leaves.
Capillary action is the main force that allows the movement of water up into plants. In a narrow tube, on a surface that attracts water, the attraction between the surface and water, coupled with the attraction of the water molecules to each other, pulls water up. Plants are composed of huge numbers of tube-shaped cells that take advantage of these physical forces.
In this experiment, you can see colored water being taken up, via capillary action, into your cabbage.
Imagine how high the water in giant redwoods has to travel to reach the leaves at the top. In very tall trees, a process called transpiration helps the water overcome the forces of gravity. Here’s a transpiration experiment you can try at home.
Halloween Halloween brings out the kid in all of us, and there’s no better way to celebrate than with some ghoulish science experiments. Next week, I’ll be adding Vegetable Vampires and Zombie Candy to the lineup!
Here’s a list of our favorites. Just click on the name of the experiment to go to the instructions, see photos of what to do, and learn a little science. Most have links to videos or TV segments where I demonstrate how to do the experiments.
Shocking Machine Make an electrophorus and Leyden jar to shock your friends! Here’s how to do it. We demonstrated it on Kare11 last week!
Frankenworms Gummy worms soaked in baking soda and water come to “life” when you drop them into vinegar! Click here for directions and a video.
Goblin Goo (All you need is cornstarch and water. Here’s a video on how to make the goo. You can add a little food coloring to the water if you want, but it may stain your hands!)
Bag of Blood (If you have ziplock baggies, water, red food coloring and skewers, you can do this experiment!) Here’s the video.
Fizzy Balloon Monster Heads (After we made Goblin Goo, I demonstrated how to make Fizzy Balloon Monster heads. Click here to watch.)
Magic Potion (Bubbly, stinky Halloween fun: I made a short video on how to make magic potion. Click here to watch it.
Mad Scientist’s Green Slime (To see a TV segment where we made Mad Scientist’s Green Slime, click here!) Here’s another video.
Apple Mummies (Here’s a link to a TV segment where the kids and I demonstrated how to make Apple Mummies. Click here.)
Alien Monster Eggs (These make a great centerpiece for a Halloween party, when you’re done playing with them.) I demonstrated how to make them on Kare 11! Click here to watch the video.
Creepy Critter Slingshots Lob Marshmallow eyeballs and spiders at a pumpkin or another target in this fun physics experiment.
Today, Target shared three of our favorite Halloween science experiments on abullseyeview.com.
Doctor Frankenstein would have loved this experiment that makes electrons jump from place to place, with a shocking conclusion. You can watch us demonstrate it on Kare11 Sunrise by clicking here.
To make an electrophorus, or charge carrier, all you need is a Styrofoam plate, a cardboard square large enough to tape the plate onto, an aluminum pie pan, a Styrofoam cup, aluminum foil and wool, like an old mitten or stocking cap.
Tape the foam cup to the inside of the pie pan. Then cover the cardboard with foil and tape the plate on to the surface, facing down.
For your Leyden jar, which can make a bigger spark and shock, you’ll need a plastic film canister or an empty spice jar*, a nail longer than the canister, aluminum foil and water.
Cover the outside of the bottom of the film canister or spice jar with foil, push the nail through the cap, fill it 3/4 up with water and replace the lid/nail so the nail is in the water. *If you’re using a spice jar, put foil on the bottom half of the jar, remove the lid, fill it 3/4 full of water, and make a new “lid” by covering the top of the container with duct tape. Stick your nail through the duct tape and your Leyden jar is ready to go! If your nail doesn’t stay in place, use more duct tape to secure it!
Now rub the foam plate with wool for about a minute. The Styrofoam attracts electrons from the wool, giving the plate a negative charge.
It’s important to do the next steps in order!
1. Put the pie tin on the foam plate. The electrons on the pie tin are repelled by the negative charge on the plate, but they can’t go anywhere.
2. Put your thumb on the foil at the bottom and leave it there while you touch the pie tin with a finger on the same hand. You should feel a small spark as the electrons jump from the pie plate to your hand, leaving the plate with a positive charge.
3. Lift the plate using the foam cup and touch it to the head of the nail on your Leyden jar. Electrons will flow from the nail to the pie plate, leaving the nail and inside of the jar with a positive charge. Repeat steps 1-3 a few times to build up a charge in your Leyden jar.
4. When you’re ready for a shock, put your thumb on the foil on the bottom of your Leyden jar, leave it there, and bring your fingertip close to the nail on the jar. Electrons will jump from the negatively charged foil on the bottom of the jar to the positively charged nail, giving you a shock. If you try it in the dark, you may see a spark as the electrons move through the air to your finger!
When you’re tired of getting shocked, you can always whip up a batch of color-changing, bubbling Magic Potion! Click here for directions and a video.
If you love marshmallows, you’ll love this physics experiment for Halloween. We’ve taken our ordinary Marshmallow Slingshot experiment to a spooky new level by adding edible tattoos to the marshmallows for Halloween. (We found them online at Oriental Trading Company.)
They’d be perfect for any Halloween party. Set up some pumpkins as targets and watch elastic energy turn into kinetic energy as you fire away. Click here to see the original post and learn about conservation of energy.
A fun video about making these slingshots and showing them in action is on both the free and Premium versions of KidScience app for iPhones and iPod touch.
You’ll be amazed when you fill a plastic zip-lock bag with “blood” and poke sharp skewers through, only to find that the bag doesn’t leak! All you need is a ziplock bag, water, food coloring and wooden skewers. Heavy-duty ziplocks work best! Fill a quart-sized ziplock bag with water, add a few drops of red food-coloring, and seal it. Slowly poke several wooden skewers completely through the bag, from one side to the other, avoiding the part with air in it. See how many you can push through! (Remember to be careful with the sharp points and I’d recommend putting a bowl underneath to collect drops.)
Why doesn’t the bag leak? Plastic is a polymer, made up of long, elastic molecules that form a seal around the spot where the skewer is poking through. In addition, the bag is sealed and contains very little air, so there isn’t much air pressure pushing on the water. If you make a hole in the part of the bag with air in it, surrounding air pressure (atmospheric pressure) can push on the liquid and make the bag leakier!
What could be more fun than creating your own green slime to play with? It’s easy to synthesize your own green goo using only Elmer’s glue (the non-washable kind), Borax (found in the laundry detergent section of Target and some grocery stores), green food coloring and water.
Mix together about 1/3 cup glue and 1/3 cup water with a spoon or Popsicle stick. These measurements don’t have to be exact. Add a few drops of green food coloring and stir.
To make the Borax solution, add around a cup of water to a jar. To the water, add about a Tablespoon of Borax. Shake or stir to dissolve as much of the Borax as possible. You’re making a saturated solution, so it may not all dissolve!
Here’s the fun part: Add a teaspoon at a time of the Borax solution to the glue/water mix. After each addition, stir the mixture. You’ll see long strings begin to form and stick together. Keep adding Borax until the mixture doesn’t feel sticky. It will form a shiny playdough-like substance. If you add too much Borax solution, it will feel wet, but you should be able to squish it around in your hands to absorb the extra water! The slime isn’t toxic, but Borax is soap, so don’t eat it!
What happens? Mixing Elmer’s glue with water forms a substance called a polymer, which is a long chain of molecules, sort of like a string of pearls. (A molecule is the smallest amount of a specific chemical substance that can exist alone, like H2O, a single water molecule). The polymer formed by water and glue is called polyvinyl acetate.
The Borax solution (sodium tetraborate) is a cross-linking substance that makes the polymer chains stick together. As more and more chains stick together, they can’t move around and the goo gets thicker and thicker. Eventually, all the chains are bound together and no more Borax solution can be incorporated.
You can store the slime in plastic bags. If you want to make a larger batch, just remember to mix equal amounts of glue and water and then add as much Borax solution as needed.