Heading to one of our wonderful hands-on science museums may not be wise during the coronavirus outbreak. But there are still plenty of opportunities for science fun and learning at home.
Try out one of these Science Snacks from a Bay Area favorite, the Exploratorium in San Francisco. Most of these experiments use everyday materials you may already have at home. You can find dozens more ideas on subjects ranging from biology to chemistry to physics at exploratorium.edu/snacks.
Remote Control Roller
Rub a balloon on your head, then watch a soda can race across the floor or a table. As you observe the interplay between electrons and protons, you’ll also discover why clothes cling together in a dryer.
Tools and Materials:
• Empty soda can
• A balloon
• Your hair (Dry, not-too-short hair with no hair products in it works best.)
• A flat surface such as a table or a floor
Assembly:
Inflate the balloon and tie it off.
To Do and Notice:
Put the can on its side on a table or the floor – any place that’s flat and smooth. Hold it with your finger until it stays still.
Rub the balloon back and forth quickly on your hair.
Hold the balloon about an inch from the side of the can. The can will start to roll, even though you’re not touching it.
Move the balloon away from the can – slowly – and the can will follow the balloon. If you move the balloon to the other side of the can, the can will roll in the other direction.
How fast will the can roll? How far can you roll the can before it stops? Will it roll uphill?
Invite some friends over – have them bring their own cans and balloons – and have a race across the room or down the sidewalk.
For more information about What’s Going On and further exploration, visit exploratorium.edu/snacks/remote-control-roller.
Ice Balloons
Have a ball experimenting with a frozen water balloon – and learn about water chemistry, phase changes and density.
Tools and Materials:
• 9-inch spherical balloons (12-inch will also work)
• Water faucet (or some other way to fill balloons)
• Access to a freezer
• Plastic tub big enough and deep enough to float an ice balloon: 12 by 12 by 9 inches or larger
• Scissors
• Cafeteria-style plastic tray (to catch the meltwater)
• Salt
• Food coloring
Assembly:
1. Stretch the neck of a balloon over a faucet and carefully fill with tap water. Work slowly to avoid pumping a lot of air into the balloon. When the balloon is at least 5 inches in diameter, remove it from the faucet, squeeze out the air at the top, and tie it closed.
2. Make as many water-filled balloons as you will need. Then put them in the freezer and allow them to freeze for at least two days.
3. When everything is ready, fill a plastic tub with enough water to float an ice balloon. Don’t fill it all the way to the brim; leave room for the water to rise when you add the balloon.
To Do and Notice:
Cut off the neck and peel the balloon off the ice.
Put the ice balloon on the cafeteria tray and start by just taking a close look at it. What do you notice? A few things to look for are clear ice near the surface of the balloon, bubbles inside (some elongated, some making chains), the opaque center and frost forming and then disappearing from the ice balloon’s surface.
Sprinkle a small amount of salt on top of the balloon – about half a teaspoon. Then wait and watch. Notice how liquid water forms around the salt, creating meandering patterns as it flows down the balloon. Put a few drops of food coloring onto the salt to make the flow patterns more obvious.
Finally, rinse off the salt and food coloring and put the ice balloon into the water basin. Notice how it floats. How much of the balloon is above the water level, and how much is below?
For more information about What’s Going On and further exploration, visit exploratorium.edu/snacks/ice-balloons.
Marshmallow Puff Tube
Experiment with cardboard tubes of different lengths to see how far you can blow a marshmallow.
Tools and Materials:
• One file folder (or other stiff paper or lightweight cardboard)
• Scissors
• Masking tape or transparent tape
• One or more full-sized marshmallows
• A few spoonfuls of flour
Assembly:
1. Cut a rectangle from the file folder, measuring about 11.5 by 7.5 inches.
2. Place one of the long edges of the file folder inside the other and tighten to form a tube that fits around the circumference of a marshmallow. The tube should be snug around the marshmallow, but not so tight that the marshmallow isn’t able to move. It may be easier to make the tube if you first pull the folder over the edge of a table to give the material a slight curve.
3. When the tube has been rolled to the appropriate size, tape it once so it stays rolled, and then tape the entire length of the seam.
To Do and Notice:
Roll the marshmallow in flour, then shake it or tap it to remove any excess (this will help prevent the marshmallow from sticking to the tube).
Place the marshmallow in one end of the tube. Hold the other end of the tube up to your mouth, parallel to the floor, and blow hard into the tube. Notice how far the marshmallow goes.
Again place the marshmallow in one end of the tube, but this time put your mouth up to the same end of the tube where the marshmallow is located. Blow hard against the marshmallow itself, so that it has to travel the length of the tube before exiting. Be sure to keep the tube horizontal, and keep blowing the whole time the marshmallow is in the tube. Did the marshmallow go farther this time?
If you blow and the marshmallow won’t move, check the diameter of the tube. It may either be too tight (in which case friction prevents the marshmallow from moving) or too loose (in which case air blows right by the marshmallow instead of pushing it).
For more information about What’s Going On and further exploration, visit exploratorium.edu/snacks/marshmallow-puff-tube.