Coin Curiosity

Children will learn about bankers as community helpers and perform an experiment using water and coins.

Lesson Objective

Children will learn about the role of a banker as a community helper and use coins to experiment with water on surfaces.


What You'll Need

  • Coins - a penny, nickel, dime, and quarter for each child
  • Eyedroppers - one for each child
  • Small paper or plastic cups - one for each child
  • Paper towels
  • Chart paper and marker
  • Water

What To Do

  1. Explain to the children that banks are a special kind of business that help us to save and manage our money. People who work in a bank have a variety of jobs; talk about the different jobs.
  2. Ask the children, “Have you ever been to a bank?” "What did you see at the bank?” "What did you do at the bank?”
  3. Let’s look at some money. Show the children the coins. “Do you know the names of any of these coins? We use money to pay for things. Today, we are going to use these coins to experiment with water."
  4. Ask the children some probing questions: “What would happen if I placed a drop of water on a penny?” “How many drops of water do you think will fit on a penny?”
  5. Encourage them to make predictions. Record each child’s prediction on the chart paper.
  6. Give each child an eye dropper, a small cup of water, a penny, and a paper towel. Have them spread out the paper towel and place the cup and coin on the towel.
  7. Show them how to use the eye dropper to place a single drop of water on the penny. Have them observe the drop of water, does it stay on the penny?
  8. Give the children time to place additional drops of water onto the surface of the penny. Remind them to count the number of drops as they do this.
  9. Ask each child how many drops they fit onto the penny before the water rolled off. Write their answers next to their predictions.
  10. Are students surprised by how many drops fit on the surface of their pennies? Were their predictions accurate? Did everyone fit the same number of water droplets onto their penny?
  11. Give each child a nickel, a dime, and then a quarter and let them try the experiment with each of the coins.
  12. What do they notice about the different coins and the amount of water that they can hold?

Guiding Student Inquiry

  • How does the water stay on the coins?
  • Why does the water eventually roll off the coins?
  • Which coin(s) hold more water? Why?
  • Use other objects such as balls and funnels. How does the water fall differently over the coins than the ball? The funnel?
  • What do we use money for?
  • Do you think they do activities with water and coins at the bank?

Explore, Extend & Integrate

  • Try the experiment again using the back of the coins. Compare the results with the results from the experiment using the front of the coins. Is there any difference in how much water they could hold?
  • Try other liquids, such as soapy water, oil, or milk.
  • Turn your dramatic play area into a neighborhood bank. Provide adult work clothing such as dresses, suits, and ties. Include a cash register and play money. Go to a local bank and ask if they will donate some deposit and withdrawal slips, coin wrappers, or other related items. Include paper and crayons or markers.

Check for Children’s Understanding

  • Were the children able to make predictions about the the coins and the water?
  • Did the children understand why different coins were able to hold different amounts of water?


Did You Know?

Banks are a special kind of business in our community. They help us to save and manage our money. People who work in a bank have a variety of jobs. The bank teller is the person who greets you at the bank and helps you with deposits (putting money into your bank account) and withdrawals (taking money out of your bank account).

The water droplets gather and stay on the surface of a coin as a result of surface tension. Water molecules do not like to separate from each other, so they cling together. The molecules that are closest to the surface, like the outside of a water droplet, cling even tighter to the water molecules that are near it. The water molecules on the surface of the droplet hold on to the other water molecules so tightly that they form a tight surface. If the water is on a smooth surface, like a coin, a rounded surface or droplet is created.

The United States mint is responsible for making all of our money. The mint began making money in 1792. The mint produces millions of coins a day. Pennies are made from a combination of the metals copper and zinc. Nickels, dimes, and quarters are made from a combination of copper and nickel.

Vocabulary: Child-Friendly Definitions

  • bank – a business in a community that keeps your money safe and lends money to people.
  • banker – a person who owns a bank or works in a bank.
  • coin – a small, flat, round piece of metal that is used as money.
  • droplet – liquids like water or juice can form droplets on things like tables or windows. The droplet is small and round on the top and flat on the bottom.
  • money – coins or paper bills that we use to buy things or pay for things.
  • water – the clear liquid that is in rain and that comes out of our faucets; we drink it.

Lesson Tips

  • Some children may have difficulty using the eye dropper. You may want children to work in pairs so they can help each other.
  • The children might get wet, smocks are a good idea.


  • Money, Money, Honey Bunny! by Marilyn Sadler
  • One Cent, Two Cents, Old Cent, New Cent: All About Money by Bonnie Worth
  • Little Critter, Just Saving My Money by Mercer Mayer

Home School Resources

Home educators: use these printable lesson PDFs to teach this lesson to your home schoolers. They're available in English and Spanish.

Home/School Connections

Las Conexiones a la Casa

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Content Provided By

Common Core State Standards Initiative – These lessons are aligned with the Common Core State Standards ("CCSS"). The CCSS provide a consistent, clear understanding of the concepts and skills children are expected to learn and guide teachers to provide their students with opportunities to gain these important skills and foundational knowledge [1]. Visit the CCSS