demonstrations:pouring_water_down_string

Pouring Water Down a String

Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required

Categories: Fluids and Surface Tension

Alternative titles: Water String Trick, Cohesion and Adhesion Demonstration, Travelling Water

Summary

Water is poured from one container into another along a piece of string. The demonstration shows how the adhesive and cohesive properties of water allow it to cling to the string and flow downward instead of falling freely.

Procedure

  1. Cut a piece of cotton string or yarn about 60 cm long.
  2. Tape one end of the string to the inside bottom of a glass.
  3. Fill a measuring cup with water.
  4. Soak the free end of the string in the measuring cup for about 30 seconds until it is fully wet.
  5. Raise the measuring cup about 30 cm above the glass, holding the string taut but not pulling it free or letting it touch the side of the glass.
  6. Slowly pour water from the measuring cup so that it travels along the string into the glass.

Traveling Water Experiment | Cohesion and Adhesion in Water Explained | Science Experiment for Kids - Hungry SciANNtist:


Pouring water down a string experiment - Phil McCordic:


📄 Pour Water Down a String! - Blue Marble: https://thinkbluemarble.com/learning-galaxy/activity-lab/pour-water-down-a-string/

Variations

  • Try using different types of string (cotton, nylon, wool) to see which works best.
  • Test different string lengths to find the maximum distance water can travel.
  • Change the angle of the string to compare how slope affects water flow.
  • Try using a stirring rod to pour from one beaker to another (this is actually a technique use in science laboratories).

Safety Precautions

  • Work on a waterproof surface or place a towel underneath to catch spills.
  • Pour slowly to prevent splashing.

Questions to Consider

  • Would water flow down a dry string? (No, because adhesion requires the string to be wet first.)
  • How does the angle of the string affect the water’s flow? (Steeper angles generally allow smoother flow.)
  • What happens if the string touches the side of the glass? (The water may run down the glass instead of along the string.)
  • What property of water makes it stick to itself? (Cohesion.)
  • What property of water makes it stick to the string? (Adhesion.)