How Many Drops of Water Can Fit on a Penny?

The Experiment

Have you ever wondered how many drops of water a penny can hold? It’s a fun interesting experiment that you can do with your kids or friends to learn about surface tension water properties. The experiment is simple requires only a few materials:

• A clean penny
• An eyedropper or pipette
• Water

The Procedure

1. Clean the penny with rubbing alcohol or soap water to remove any dirt or oil.
2. Fill the eyedropper or pipette with water.
3. Slowly add one drop of water at a time onto the penny’s surface counting each drop.
4. Continue adding drops until the water spills over the edge of the penny.
5. Record the number of drops before the water spills over.

The Results

The number of drops of water a penny can hold varies depending on the coin’s condition your technique. On average a penny can hold about 30-35 drops of water before spilling over. However some pennies may hold more or less depending on their surface tension any defects on the coin’s surface.

The Science Behind It

Water has properties that allow it to hold a certain volume of liquid depending on the surface tension. When drops of water adhere to the penny’s surface they create a dome-like shape that has a slight upward curve at the edges. As you add more drops the surface tension of the water holds the liquid in place until the water cannot resist gravity any longer it spills over.

The Takeaway

The number of drops of water a penny can hold may seem insignificant but it provides insight into the properties of water surface tension the effect of gravity. It’s a simple experiment that you can do at home with household items it’s a fun way to learn about science while also having fun with friends or family.