chapter 4
BLOW
IT UP
How would you make a marshmallow bigger? By pulling on the corners? By stretching it out? Could you do it without using your fingers?
In this chapter, you’ll learn all sorts of ways to make candy bigger—without touching it. Read on to find out how air, heat, or water can blow up your candy.
Caution: Some of these experiments involve heating candy in the microwave. Ask a grown-up to help you with these. Hot candy can be hotter than boiling water, so don’t touch!
Time: 5 minutes
Skill Level: Get a grown-up
Hot air puffs up a hot air balloon. You can try the same thing at home—in your microwave.
What you need:
Marshmallow or Peeps marshmallow candy
Microwave-safe plate
Microwave
What to do:
1 Put the marshmallow on the plate and microwave it to watch it expand (30 seconds to 1 minute).
2 When the microwave stops, open the door. As the marshmallow shrinks, listen for the hiss of air escaping from the marshmallow. Hold your hand over it—can you feel the hot air moving?
What’s happening:
Marshmallows are made of air bubbles trapped in a mix of water, sugar, and gelatin. When you microwave them, the water heats up, softening the sugar and warming the air. The hot air expands, pushing out the sides of the soft marshmallow like a balloon. But it can’t last forever. As the marshmallow cools, the bubbles shrink and collapse as hot air escapes, leaving a puddle of marshmallow goo.
A Peeps chick becomes a giant chicken in the microwave.
more fun
Make a marshmallow pyramid with three on the bottom and one on top. Microwave the marshmallows. How tall does your pyramid get?
Time: 5 minutes
Skill Level: Get a grown-up
You can microwave marshmallows and make them expand. Can you do this with any other candy?
What you need:
3 Musketeers bar (unwrapped)
Microwave-safe plate
Microwave
What to do:
1 Put the 3 Musketeers bar
on the plate.
2 Microwave it until it expands and starts to bubble (30 seconds to 1 minute, depending on the size of the bar).
What’s happening:
Like marshmallows, a 3 Musketeers bar contains air bubbles. When you microwave it, the air bubbles heat up and expand, pushing out the sides of the candy bar.
Microwaved 3 Musketeers bar.
more fun
What other candies contain air bubbles? Microwave them and see what happens.
Time: 5 minutes
Skill Level: Get a grown-up
Can you make a cratered moonscape in your microwave?
What you need:
Chocolate-covered marshmallow, such as a chocolate bunny, egg, pumpkin, or Santa
Microwave-safe plate
Microwave
What to do:
1 Put the chocolate-covered marshmallow on the plate.
2 Microwave it for 30 seconds to 1 minute. Do you see the marshmallow growing? Do you see how the chocolate creates craters in the marshmallow?
What’s happening:
When you microwave a marshmallow, the air bubbles expand, pushing out the sides of the marshmallow (see the Enormous Expanding Marshmallow experiment). But the chocolate doesn’t expand. Instead, it melts and breaks into pieces. These pieces weigh down the marshmallow, creating craters.
Time: 2 hours to 2 days
Skill Level: Easy
Gummi candy grows bigger as it absorbs water. How big can your gummi get?
What you need:
Gummi candy containing
gelatin, such as gummi worms, Life Savers Gummies, or gummi
fruit snacks
Bowl of water
What to do:
1 Put the gummi candy in the bowl of water.
2 Check the candy after a few hours. Is it expanding?
3 Wait a couple of days. How big did your gummi candy grow? (Since different gummi candies are made using different recipes, some don’t expand in water. If your candy didn’t grow, try a different kind.)
What’s happening:
“A dehydrated gummi worm is an unhappy gummi worm,” says one scientist. That’s because gummi worms absorb water. Lots of water.
Gummi candies are made with gelatin, a tangle of long protein molecules. (The tangled molecules don’t break apart easily, which makes gummies stretchy.) When you put gelatin in water, the protein pulls the water into the tangle and the candy expands. Eventually, it absorbs so much water that the molecules spread apart and untangle, which makes the candy fall apart more easily.
As the gummi candy absorbs more and more water, it starts to resemble a different kind of gelatin dessert. Jell-O is also made of gelatin, sugar, and water. So when you expand your gummi candy, you’re making something like Jell-O.
A two-day soak turns gummi worms into gummi snakes.
more fun
If you want to find out how much water your gummi worm absorbed, weigh it before and after the experiment. The added weight is the extra water. (If your gummi candy breaks, try lifting it with a slotted spoon or pouring the water and candy onto a plate.)
Time: 15 minutes
Skill Level: Get a grown-up
Can you make marshmallows dance without touching them?
What you need:
Small bottle with a lid, such as an empty jam or peanut butter jar
A drill or a hammer and nail
Marshmallows
Rubber band
Bicycle pump
What to do:
1 Have a grown-up help you drill or hammer a hole through the lid of the jar. Try to make the hole the size of the bicycle pump nozzle.
2 Fill the jar with marshmallows.
3 Wrap the rubber band several times around the bicycle pump nozzle.
4 Insert the nozzle in the air hole in the lid of the jar. Slide the rubber band down to block air from escaping. Screw the lid onto the bottle.
5 Pump a few times. If too much air escapes from the bottle, try moving the rubber band to the underside of the lid to block air from that direction.
6 Pump air into the bottle and watch your marshmallows dance.
What’s happening:
A marshmallow’s size depends on air. Air bubbles inside the marshmallow push out, making it puffy. Air outside the marshmallow pushes in.
When you pump air into the bottle, air pushes against the marshmallows, causing them to shrink and move. When the air escapes from the bottle, the marshmallows expand back to their original size.
Pumping air into this bottle makes the marshmallows dance.
more fun
Try this with Peeps hearts. The hearts will look like they’re actually beating.
Time: 5 minutes
Skill Level: Get a grown-up
Air bubbles inside a marshmallow push outward, but the air outside pushes back in. What happens if you remove some of the outside air?
What you need:
Marshmallows
FoodSaver vacuum sealer and container
What to do:
1 Place a marshmallow inside the FoodSaver container.
2 Seal the container.
3 With a grown-up’s help, attach a hose to the container and to the vacuum sealer (see the FoodSaver instructions for more details).
4 Turn on the FoodSaver to vacuum air out of the container. Does the marshmallow expand? When you open the container to let air back in, does the marshmallow shrink? Does it look even smaller than when you started?
What’s happening:
When you turn on the FoodSaver, you’re vacuuming air out of the container. With less air pushing against the marshmallow, the air bubbles inside the marshmallow expand, making it grow.
After you unsealed the container, did your marshmallow look small and wrinkled? This may happen because air bubbles inside the marshmallow break open as the marshmallow expands, letting air leak out. With less air inside the marshmallow, it shrinks to a smaller size when the air pressure returns to normal.
Vacuuming air out of this bottle makes the marshmallows expand.
more fun
Try filling the container half-full of marshmallows. When you turn on the vacuum, how much do the marshmallows expand?
Time: 5 minutes
Skill Level: Medium
Did you know that candy can cause an eruption? To see how, try this. This experiment can get messy, so make the fountain outside, and wear old clothes.
What you need:
Toilet paper tube
Package of mint or fruit Mentos
2-liter bottle of Diet Coke
What to do:
1 Cut the toilet paper tube lengthwise, cut off a 1-inch-long strip, and then wrap the tube around the Mentos package. When you can easily slide the Mentos in and out, tape the sides together.
2 Open the Coke bottle and the Mentos package.
3 Fill the cardboard tube with Mentos. Block the bottom with the cardboard strip.
4 Hold the tube over the Coke bottle opening. When you’re ready, remove the strip and let the Mentos fall into the Coke. Then get out of the way!
What’s happening:
Soda pop is full of carbon dioxide gas. When you drop in Mentos, bubbles of carbon dioxide form on the surface of the candy. So many bubbles form so fast that they push the soda right out of the bottle.
Why use Mentos and Diet Coke? The rough surface of Mentos creates lots of places for bubbles to form. As they form, more carbon dioxide turns into gas and makes the bubbles bigger. More gas is released. Mentos also contain gum arabic, a surfactant, which decreases surface tension in the soda, so that bigger bubbles can grow. Diet Coke also contains surfactants.
Soda explodes skyward after Mentos are dropped into the bottle.
more fun
Try dropping other kinds of candy in soda. Which kinds make the most bubbles? Do any work as well as Mentos?
