Pour Water down a String | STEM Activity

The Pour Water down a String is a super simple and easy STEM activity for preschool at home with simple materials. Learning by doing is the best way of learning for toddlers.

Age: 3+       Time: <10min

 Safety 

1. Adult supervision.
2. Be careful with the fragile glass.

 Materials List 

• Beaker
• Water
• String
• Tape
• Food coloring

 Instruction 

Step 1/4 – Soak the string into the water.

Step 2/4– Fix one end of the string on a beaker inside the bottom. Pull it to test if it is firmly fixed.

Step 3/4 – Add a few drops of food coloring into a glass of water.

Step 4/4 – Hold the unfixed end of the string and tighten it, slowly pour the water along the string, and see the water clings to the string and goes into the empty cup without spilling.

 Troubleshooting 

Why is my water spilling to the ground?

— It can be that you were pouring water too fast, the rope is not fully tightened, or the rope is not soaked in advance.

 Scientific Description 

The water has both a strong “cohesive” and “adhesive” trait. Adhesion: The ability of a substance to stick to an unlike substance; the attraction between unlike molecules. Cohesion: Various intermolecular forces that hold solids and liquids together; the attraction between like molecules. At the molecular level, the water has two hydrogen atoms with positive charges and one oxygen atom with negative charges. Because of the different charges, they can stick to one another, even to charges in another atom. Thus, water molecules stick to each other. That is why water makes a nearly spherical drop. In this experiment, you soak the string in advance so there are many water molecules on the string which will cling to the water you pour, preventing the water from falling down vertically.

 Extensions 

At what angle, you can pour the water without spilling it out.