4.6. Surface Tension

Try these first

1. 1.

   Define surface tension.

   Hint

   Think about the forces at the surface of a liquid.

2. 2.

   What are cohesive forces?

   Hint

   Consider why water droplets stay together.

3. 3.

   What acts as the main force creating surface tension?

   • Adhesive Forces
   • Cohesive Forces
   • Gravitational Forces

   Hint

   Think about the forces that hold liquid molecules together.

4. 4.

   Surface tension increases with temperature. True or False?

   • True
   • False

   Hint

   Consider the effect of heating on molecules.

5. 5.

   A water droplet has a radius of 2 mm. Calculate the surface tension force acting on the droplet if the liquid's surface tension is 0.072 N/m. Use the formula f = surface_tension * circumference.

   Hint

   Don't forget to calculate the circumference first!

6. 6.

   If the surface tension of mercury is 0.485 N/m, what is the pressure difference across a mercury drop with a radius of 5 mm?

   Hint

   Use the surface tension relation formula.