Evaporation and Condensation _ GCSE Physics

The video explains the processes of evaporation and condensation. Evaporation occurs when particles in a liquid gain enough energy to become gas, cooling the remaining liquid. This is why sweating cools the body. Factors like temperature, surface area, and air movement can increase evaporation. Condensation is the reverse, where gas turns into liquid, releasing energy. This energy release can cause burns when steam condenses on the skin.

What happens to the average kinetic energy of the remaining liquid particles during evaporation?

• It increases.

• It decreases.

• It remains the same.

• It fluctuates randomly.

Which of the following factors does NOT increase the rate of evaporation?

• Higher temperature of the liquid

• Decreasing the temperature of the liquid

• Larger surface area of the liquid

• More violent air movement over the surface

Why does sweating help cool the body?

• It reduces the blood flow to the skin.

• It blocks the pores on the skin.

• It increases the body temperature.

• It absorbs energy from the skin to evaporate.

What occurs during condensation?

• Gas particles gain energy and spread out.

• Gas particles lose energy and form bonds.

• Liquid particles gain energy and evaporate.

• Liquid particles lose energy and freeze.

Why can steam cause burns when it touches the skin?

• Steam is cold and absorbs heat from the skin.

• Steam is hot and releases energy as it condenses.

• Steam is dry and dehydrates the skin.

• Steam is acidic and reacts with the skin.