Easy Cork Meniscus Experiment

Ever wonder why cork floats to the side of a glass of water? Learn all about molecules and menisci with two easy experiments below!

What you need:

Glass of water

Wine cork

How to do the meniscus experiment:

1. Fill a glass halfway with water.

2. Carefully place a cork in it and watch it float to the edge.
3. Take the cork out.
4. Fill the glass to the top with water, being careful to not cause it to spill but making sure there is a dome of water over the glass.
5. Carefully place a cork in the water and watch it stay in the middle.

What’s going on?

When you fill a glass halfway with water, the water molecules are attracted to the glass container, causing them to cling to the side. Because of water’s adhesive properties, more water is attracted to the molecules already on the side of the container, resulting in a negative meniscus. Since cork is buoyant in water, it floats to the edge of the glass where the water level is the highest. When the glass is overfilled, the water forms a positive meniscus due to surface tension preventing it from spilling over the sides. When a cork is placed in the overfilled glass, it floats in the center because the water level is highest there.