In this activity, your child will separate salt and pepper using static electricity.
Learning Area(s): Science
MATERIALS
- 2 teaspoons salt
- 1 teaspoon ground pepper
- dry fabric (wool or a fluffy towel)
- small plate
- 3 spoons (1 plastic, 1 wood, 1 metal)
- journal, notebook, or a few sheets of paper stapled together
- pencil
LET'S PLAY
Before the activity, pour two teaspoons of salt on a small plate. Set the teaspoon of pepper aside.
Activate your child’s background knowledge by asking, “Do you remember a time when you touched someone or something and felt a little zap?” Talk about how it felt. “That little zap is a kind of electricity called static electricity.” Talk about other examples of static electricity in the home, like socks sticking to shirts when they come out of the dryer, or hair standing up when you take off a hat or sweater in the winter. “We are going to experiment with static electricity to learn about how it works! You will use static electricity to separate salt and pepper.” Allow your child to gently mix the pepper with the salt.
Experiment steps for each spoon:
- Have your child hold the (wooden, plastic, metal) spoon about half an inch above the mixed salt and pepper. Ask, “What do you observe (see) happening?” (Nothing.)
- “Next, you’ll rub the spoon against this fabric. What do you think will happen when you test the spoon again?” Allow your child to share their prediction and write it in their journal. Have them rub the bottom of the spoon back and forth quickly against the fabric about 10 times.
- Your child should immediately hold the spoon about half an inch above the pile. If the spoon doesn’t attract any pepper, have them rub the spoon and try again. (Note: Static electricity will stay on the plastic spoon but not the others.) Ask, “What do you observe now?” Have them write their observations in their journal.
- Dust any salt and pepper back into the pile.
- Repeat steps 1-4 with the other two spoons.
After testing all of the spoons, ask your child, “How did the type of spoon change what you observed?” Encourage your child to draw a conclusion about static electricity, fabric, and plastic objects based on the results of the experiment.
Explain how static electricity occurs. You can say, “Did you know that everything in the world, including you and me, is made of particles? What does the word part-icle make you think of?” Allow time for your child to respond. “Particles are very tiny parts of what something is made of. Particles are such tiny parts that they are too small to see. Scientists know that some of those tiny parts are positive and some are negative. That doesn’t mean some are good and some are bad. Positive and negative are scientific words that describe how much electricity is in particles. When something has more negative particles, it has a negative charge. When something has more positive particles, it has a positive charge. Negatively charged and positively charged particles move toward each other. In our experiment, how did we try to give the spoons a negative charge? Allow time for your child to respond. “By rubbing it against the fabric, we gave the plastic spoon a negative charge to try to make static electricity on the surface. The positively charged particles in the pepper were attracted to the negatively charged plastic spoon.”
You can ask and discuss questions like:
- “Do you think other plastic things could create static electricity when rubbed on a piece of fabric? How can you find out?” (All kinds of plastic will hold onto an electric charge.)
- “Do you think all kinds of fabric help create static electricity?” (Wool, silk, polyester, acrylic, and rayon will also work. Cotton and leather do not work because they hold onto moisture.) “How could you test that?”
- “Are there any other materials you want to test?”
- “What other things could you attract using static electricity?” (Examples: Hair/fur, dust, paper)
- “Why do you think the negatively charged spoon only attracted the pepper?” (The pepper weighs less than the salt.)
TIPS
- Try this activity when the air is dry instead of humid. If the air is humid, more water is in the air. Microscopic water molecules can collect on some materials which keeps them from building up electrical charges. This makes it more difficult to create static electricity.
- Rubbing a neutral item on something made with wool can help create a better charge. Some items you might have that are made with wool might be yarn, socks, sweaters, hats, mittens, carpets, blankets, ponchos, etc.
- Use one or all of these resources to learn more about static electricity.
- book: Fun with Static Electricity: Static Electricity (Science Storybooks) by Chocolate Tree
- website: How Does Static Electricity Work?
- video: “Static Electricity: Snap, Crackle, Jump”
- To extend this activity, collect an assortment of items from around the home made of different plastics, silicone, and rubber to rub on the fabric to see if they can create static electricity to pick up pepper. Alternatively, you could use the plastic spoon to try to attract different spices or baking materials.