Atmospheric Energy & Circulation — Drills · Grade 9 Science

Chapter: Atmosphere & Weather

What these drills covers

By the end of Atmospheric Energy & Circulation you should be able to:

8 questions, numeric, written answer and multiple choice, each with a worked explanation.

Vocabulary used: albedo, convection, latent energy transfer.

Problem 1

A surface reflects 30 out of 100 incoming units. Find its albedo as a percentage.
Answer and explanation

30 %

30 ÷ 100 × 100 = 30.

Problem 2

What does Earth’s rotation do to large-scale air motion?
Answer and explanation

It deflects motion relative to the surface and helps organize circulation patterns.

Problem 3

Warm air rises because it is
  1. heavier
  2. less dense than the cooler air around it
  3. attracted upward
  4. pushed by the Sun
Answer and explanation

less dense than the cooler air around it

Heating expands air, lowering its density so it is buoyant.

Problem 4

The equator receives more energy per unit area than the poles because sunlight there strikes
  1. from further away
  2. more directly
  3. through more atmosphere
  4. at night
Answer and explanation

more directly

A steeper angle concentrates the same beam on a smaller area.

Problem 5

Global circulation cells exist mainly because of
  1. uneven heating between equator and poles
  2. the Moon
  3. ocean salinity
  4. volcanoes
Answer and explanation

uneven heating between equator and poles

The temperature difference drives air to move, redistributing energy.

Problem 6

Earth's rotation deflects moving air, an effect called
  1. convection
  2. the Coriolis effect
  3. conduction
  4. radiation
Answer and explanation

the Coriolis effect

It is why winds curve rather than flowing straight from high to low pressure.

Problem 7

Explain why deserts are common near 30° latitude.
Answer and explanation

Air that rose at the equator and lost its moisture as rain travels poleward aloft and descends around 30°. Descending air warms and its relative humidity falls, so cloud and rain are suppressed. The dryness is a consequence of the circulation pattern rather than of local conditions, which is why deserts appear at similar latitudes on several continents.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

Problem 8

Explain how the atmosphere moves energy from the equator toward the poles.
Answer and explanation

Air heated at the equator rises and flows poleward at altitude, carrying energy with it as both temperature and latent heat in water vapour. It cools, descends and returns toward the equator near the surface. Storm systems in the mid-latitudes carry further energy poleward. Without this transport the tropics would be far hotter and the poles far colder than they are.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

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