Explore the magic-like properties of water with this fun experiment!
Materials
- 2 identical cups (clear glasses would work best)
- Water
- Spoon or stir stick
- Food colouring
- Paper towel
How to Do The Walking Water Experiment
Step 1
Take your two empty glasses and place them about 2 inches apart from each other.
Step 2
Pour water into one of the glasses so that it is halfway full.
Step 3
Add the food colouring colour of your choice to the water. Stir until the water is all one colour.
Step 4
Grab a piece of paper towel that is 1-2 inches wide (use one section of the paper towel and fold it halfway until it is 1-2 inches wide).
Step 5
Put one end of the paper towel in the glass filled with water. Place the other end of the paper towel into the empty glass. Crease or fold the paper towel so that the ends are facing towards the bottoms of the cups.
Step 6
Make a prediction! What do you think is going to happen with your cups over time?
Leave the glasses and paper towel bridge to sit for an hour.
Step 7
After one hour, go back to the glasses and see what has happened!
Try This! Experiment with using different paper towels if you have more than one brand. Which one allows the water to travel the best?
What Happened to Your Water?
Over time the coloured water should have traveled up the paper towel and into the empty cup, slowly filling it with coloured water too!
Try This: Rainbow Walking Water
Repeat the same experiment, this time using 7 identical cups. Separate them each by two inches, then fill every other cup half full with water starting with the first cup. Add red colouring to the 1st and 7th cup, yellow food colouring to the 3rd cup, and blue food colouring to the 5th cup. Place your 1-2 inch wide paper towel between each of the cups. Watch as your water walks across the paper towel to create a rainbow between all of the cups.
How is the Water Able to Travel up the Paper Towel?
The water is able to travel by using a process called capillary action! The water molecules become more attracted to the fibres in the paper towel than to each other, resulting in the water travelling up the paper towel and into the empty glass. Another way to say this is that adhesion between the water molecules and the paper towel becomes stronger than the cohesion between the individual water molecules.
Where is capillary action used in nature?
Plants use capillary action to bring water from the soil to their roots then all the way up to their leaves!
What is Adhesion?
Adhesion is the process by which particles that are not the same stick together. Think of a bandaid. Bandaids are also known as adhesive bandages because they have a sticky part that allows the bandaid to stick to you.
What is Cohesion?
Cohesion is the process by which particles that are the same stick together. Water for example, is made up of many small water molecules, and each of those molecules stick together through the process of cohesion.
