The Science Behind Dew and Fog Formation

The video explains the formation of dew, frost, and fog. Dew forms when water vapor condenses on cold surfaces, a process demonstrated with a glass of chilled water. Dew point is the temperature at which air becomes saturated with water vapor, leading to dew formation. If temperatures drop below freezing, dew turns to frost. Fog forms when air temperature drops below dew point, causing water vapor to condense around dust particles, creating mist that reduces visibility.

What is the primary cause of dew formation on a glass of chilled water?

• Melting of ice

• Evaporation of water

• Condensation of water vapor

• Sublimation of ice

What happens to the kinetic energy of water vapor molecules when they contact a cold surface?

• It increases

• It remains the same

• It decreases

• It doubles

What is the term used for the minimum temperature required for dew formation?

• Dew point

• Melting point

• Freezing point

• Boiling point

What happens to dew drops when the temperature falls below the freezing point?

• They turn into rain

• They remain as dew

• They turn into frost

• They evaporate

What is the main reason for the ground becoming colder than the air during winter nights?

• The ground radiates heat

• The air absorbs heat

• The air radiates heat

• The ground absorbs heat

How does fog differ from dew in terms of formation?

• Fog forms in the air, dew forms on surfaces

• Fog forms on surfaces, dew forms in the air

• Fog and dew form in the same way

• Fog forms only at night, dew forms during the day

What role do dust particles play in the formation of fog?

• They reflect sunlight

• They provide a surface for water vapor to condense

• They increase the temperature

• They absorb water vapor

What is the effect of fog on visibility?

• It enhances colors

• It improves visibility

• It has no effect on visibility

• It restricts visibility

Which of the following conditions is necessary for fog to form?

• Temperature below dew point

• Temperature above dew point

• No dust particles

• High wind speed