Materials
● Clear plastic or glass container (e.g., petri dish or shallow dish)
● Water
● Measuring cylinder
● Pipette or dropper
● Small objects for testing (e.g., paper clip, small leaf, or coin)
● Ruler
● Stopwatch (optional)
Procedure
Part A: Cohesion
1. Droplet Test:
○ Using a pipette, carefully place water droplets on the surface of the petri dish.
○ Observe how many drops you can add before the water spills over the edge.
Record the number of drops.
○ Measure the diameter of the largest droplet before it spills over using a ruler.
2. Observation:
○ Discuss how the cohesion of water molecules contributes to the droplet's ability
to hold its shape and resist spilling.
Part B: Adhesion
1. Water on Different Surfaces:
○ Place small amounts of water on different surfaces (e.g., glass, plastic, wax
paper).
○ Observe the shape of the water on each surface. Record your observations
regarding how water behaves on each material.
2. Observation:
○ Explain how adhesion affects the behavior of water on different surfaces.
Part C: Surface Tension
1. Paper Clip Float Test:
○ Fill the petri dish with water until it is nearly full.
○ Carefully place a paper clip on the surface of the water. Note whether it sinks or
floats.
○ If it sinks, try to place it back on the surface gently to see if it can float due to
surface tension.
2. Soap Effect:
