Surface tension-Introduction

The video tutorial explores the concept of surface tension, starting with observable phenomena like oil and water not mixing and water forming droplets on surfaces. It delves into molecular forces and surface energy, explaining how surface tension arises from these forces. The tutorial covers the angle of contact and cohesion, illustrating how different surfaces interact with liquids. It also examines the behavior of drops and bubbles, capillary rise, and the role of detergents in reducing surface tension to aid cleaning. The tutorial provides a comprehensive understanding of surface tension and its applications.

What is the primary reason oil and water do not mix?

• Oil and water have different surface tensions.

• Oil and water have different colors.

• Oil is lighter than water.

• Oil is denser than water.

Why do molecules at the surface of a liquid have more energy than those below?

• They are closer to the air.

• They are more attracted to the container.

• They are less dense.

• They are only partially surrounded by other molecules.

What happens to the surface tension of a liquid as temperature increases?

• It fluctuates randomly.

• It increases.

• It decreases.

• It remains constant.

What determines whether a liquid will spread out or form droplets on a surface?

• The density of the liquid.

• The temperature of the liquid.

• The angle of contact.

• The color of the liquid.

How do wetting agents affect the angle of contact?

• They increase the angle of contact.

• They decrease the angle of contact.

• They make the angle of contact obtuse.

• They have no effect on the angle of contact.

What is the role of the angle of contact in the behavior of liquids on surfaces?

• It influences whether the liquid spreads or forms droplets.

• It changes the density of the liquid.

• It affects the temperature of the liquid.

• It determines the color of the liquid.

Why are drops and bubbles spherical in the absence of gravity?

• Due to their weight.

• Due to surface tension minimizing surface area.

• Because they are filled with air.

• Because of their color.

What is the phenomenon called when water rises in a narrow tube?

• Condensation.

• Evaporation.

• Capillary rise.

• Surface tension.

How do detergents help in cleaning greasy stains?

• By changing the color of the stain.

• By reducing the surface tension at the water-oil interface.

• By making the stain heavier.

• By increasing the surface tension.

What is the relationship between surface tension and pressure inside a bubble?

• Pressure is lower inside the bubble.

• Pressure is higher inside the bubble.

• Pressure fluctuates inside the bubble.

• Pressure is the same inside and outside the bubble.