Science experiments with things found in your purse or pocket? It sounds like a great indoor activity for the kiddos! How many drops fit on a penny? Explore surface tension of water when you try this fun penny lab with the kids. We are always on the hunt for simple science experiments and this one is just super fun and easy!
HOW MANY DROPS CAN FIT ON A PENNY?
DROPS OF WATER ON A PENNY
Get ready to add this simple penny lab activity, to your science activities this season. If you want to learn about surface tension of water, let’s dig in. While you’re at it, make sure to check out these other fun water science experiments
Our science activities and experiments are designed with you, the parent or teacher, in mind! Easy to set up, quick to do, most activities will take only 15 to 30 minutes to complete and are heaps of fun! Plus, our supplies lists usually contain only free or cheap materials you can source from home!
Simple questions to get your junior scientist thinking!
- How many drops of fit do you think will fit on a penny? (PREDICTION)
- What is happening when one drop of water meets another drop? (OBSERVATION)
- Which coin held the most water? (EXPLANATION)
- Can you think of any everyday examples of how surface tension? (APPLICATION)
Learn more about using the scientific method for kids here.
PENNY DROP EXPERIMENT
Let’s get right to investigating how many drops of water can fit on a penny. Grab your purse or rob your piggy bank, it’s time to find some pennies to experiment with!
Looking for easy science process information and free journal pages?
We have you covered…
YOU WILL NEED:
- Eyedropper or pipette
- Food coloring (makes seeing this in action MUCH easier, but is optional)
- Small bowls
PENNY EXPERIMENT SET UP
STEP 1: Add water to both of your bowls, and to one of them add green food coloring. This is an optional step if you want to see the drops a bit better.
STEP 2: Use an eyedropper or pipette to pick up and carefully drip one drop of water at a time onto the penny.
STEP 3: Count how many drops you can fit onto one penny until the water overflows. We were able to get ours up to about 27!
Go ahead and record the data for separate trials on the same coin. What can you conclude?
PENNY DROP VARIATIONS
If you want to add a little bit of variety to this experiment, swap out the pennies for nickels, dimes, and quarters. Ask your students to guess how many drops will fit on each coin. Record the date from the experiment and make a class graph chart with your results!
WHY DO SO MANY DROPS OF WATER FIT ON A PENNY?
Were you surprised to discover that a lot more drops of water fit on a penny than you predicted? We had 27 drops of water on ours!
Surface tension and cohesion is the reason you can get so many drops of water on a penny. Cohesion is the “stickiness” of like molecules to one another. Water molecules love to stick together! Surface tension is the result of all the water molecules sticking together.
Once the water has reached the edge of the penny, a dome shape begins to form. This is due to the surface tension forming a shape that has the least amount of surface area possible (like bubbles)!
MORE FUN SCIENCE WITH PENNIES
MORE FUN SCIENCE EXPERIMENTS
- Walking Water
- Rubber Egg Experiment
- Why Do Things Float In Salt Water?
- Water Density Experiment
- Magic Milk