Atmospheric Energy & Circulation — Practice · Grade 9 Science

Chapter: Atmosphere & Weather

What this practice covers

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

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

Vocabulary used: albedo, convection, latent energy transfer.

Problem 1

A surface receives 200 units and reflects 50. How many are absorbed if none pass through?
Answer and explanation

150 units

200 − 50 = 150.

Problem 2

Condensation generally…
  1. absorbs energy from surrounding air
  2. releases energy to surrounding air
  3. destroys water molecules
  4. requires sunlight in every case
Answer and explanation

releases energy to surrounding air

The phase change releases energy.

Problem 3

Why can a global wind belt fail to predict wind at one sheltered valley?
Answer and explanation

Local terrain and conditions modify large-scale circulation.

Problem 4

Two identical dry tiles, one dark and one light, receive the same sunlight. Predict a difference and name a control. Explain the reasoning in your own words.
Answer and explanation

The dark tile may warm more under the controlled conditions; real outdoor surfaces require additional evidence.

The dark tile is expected to absorb a larger share of sunlight.

Keep material, thickness, exposure and starting temperature comparable.

Response criteria

  • Use the stated conditions.
  • Show the evidence or calculation.
  • Explain the conclusion and any stated limitation.

Problem 5

Why does unequal solar heating help drive atmospheric circulation? Show the reasoning, not just the conclusion.
Hints

Actual circulation also depends on larger-scale wind and geography.

Answer and explanation

It creates temperature and pressure differences that move air and redistribute energy.

Problem 6

What distinguishes convection from radiation in an atmospheric energy diagram?
Hints

State what the supplied observations or conditions establish, and separate that from any assumption.

Answer and explanation

Convection transports energy with moving matter; radiation transfers energy electromagnetically.

Problem 7

Right and left are relative to motion, not always east and westRight and left are relative to motion, not always east and westNorthern Hemisphere: right of motionSouthern Hemisphere: left of motionBlue: selected motion. Red: deflection.
Original selected-direction Coriolis diagrams in a top-view Earth frame. Arrows compare direction only and do not represent measured accelerations. The effect depends on latitude and speed; friction and other forces are omitted.
Interpret the supplied visual model. In the Northern Hemisphere, what direction is right of an eastward-moving parcel?
Answer and explanation

Southward. Coriolis changes direction relative to the moving parcel; it does not always deflect east and does not initiate motion from rest.

Turn mentally to face each blue motion arrow, then identify its right or left side. Do not read right as a fixed page compass direction.

Southward. Coriolis changes direction relative to the moving parcel; it does not always deflect east and does not initiate motion from rest.

Response criteria

  • Read the labeled quantities, reference frame or objects correctly.
  • Explain the relation between the visual evidence and the mechanism.
  • Keep the drawing’s stated assumptions and limits in the conclusion.

Problem 8

A Northern Hemisphere air parcel initially moves north, while another moves east. Give the Coriolis deflection direction for each and explain why the effect does not begin a wind from rest.
Answer and explanation

Right of northward motion is east, and right of eastward motion is south. Coriolis modifies existing motion in the rotating Earth frame; pressure-gradient or other forces initiate the wind. The complete wind also depends on friction and other forces.

Right of northward motion is east, and right of eastward motion is south. Coriolis modifies existing motion in the rotating Earth frame; pressure-gradient or other forces initiate the wind. The complete wind also depends on friction and other forces.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

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