Atmosphere & Weather — Chapter quiz · Earth & Space Science, Grade 9

Trace water and energy through the atmosphere and interpret changing weather evidence.

Problem 1

Which process is powered directly by energy from the sun?
  1. Evaporation
  2. Runoff
  3. Gravity's pull on rain
  4. Infiltration into soil
Answer and explanation

Evaporation

The sun's energy heats liquid water, causing evaporation; gravity, not the sun, drives runoff and infiltration.

Problem 2

Which lists the water cycle processes in a correct general order, starting from ocean water?
  1. Evaporation → condensation → precipitation → runoff
  2. Precipitation → evaporation → runoff → condensation
  3. Condensation → runoff → evaporation → precipitation
  4. Runoff → precipitation → evaporation → condensation
Answer and explanation

Evaporation → condensation → precipitation → runoff

Water evaporates from the ocean, water vapor condenses into clouds, precipitation falls, and runoff then carries it back toward the ocean.

Problem 3

Roughly what percent of Earth's total water is salty ocean water?
Answer and explanation

97 %

About 97% of Earth's water is ocean saltwater; only around 3% is freshwater.

Problem 4

A maritime tropical (mT) air mass is best described as...
  1. Warm and moist
  2. Cold and dry
  3. Warm and dry
  4. Cold and moist
Answer and explanation

Warm and moist

'Maritime' means it formed over water (moist) and 'tropical' means it formed at a warm latitude.

Problem 5

Which type of front typically brings a longer period of light, steady precipitation as it slowly approaches?
  1. Warm front
  2. Cold front
  3. Occluded front only
  4. None — all fronts bring the same weather
Answer and explanation

Warm front

Warm fronts have a gentle slope and move slowly, spreading lighter precipitation out over a longer time.

Problem 6

A region is under the influence of sinking air. What kind of pressure and weather should you expect?
  1. High pressure; clear and calm
  2. Low pressure; cloudy and stormy
  3. High pressure; stormy
  4. Low pressure; clear and calm
Answer and explanation

High pressure; clear and calm

Sinking air piles up near the surface, creating high pressure, which is generally associated with clear, calm weather.

Problem 7

What does a barometer measure?
  1. Air pressure
  2. Wind speed
  3. Humidity
  4. Precipitation amount
Answer and explanation

Air pressure

A barometer measures air pressure.

Problem 8

In New York State, weather systems generally move...
  1. West to east
  2. East to west
  3. South to north only
  4. In no predictable direction
Answer and explanation

West to east

The prevailing westerlies and jet stream generally steer mid-latitude weather, including New York's, from west to east.

Problem 9

Which process returns water to the atmosphere from the ocean?
  1. Infiltration
  2. Evaporation
  3. Runoff
  4. Deposition
Answer and explanation

Evaporation

The ocean is the largest source of atmospheric water vapour.

Problem 10

Explain why most of Earth's water is not available as fresh drinking water.
Answer and explanation

The great majority is salt water in the oceans, which needs energy-intensive treatment to drink. Of the small fresh fraction, much is locked in ice sheets and glaciers or held deep underground where extraction is difficult or slow to replenish. Accessible fresh surface water in rivers and lakes is a very small share of the total, which is why supply is a local problem even on a wet planet.

Response criteria

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

Problem 11

Independent chapter check: A lake starts at 250 m³. Daily input is 40 m³ and output 28 m³ for five days. Find final storage and explain why the height change cannot be determined from these data alone.
Answer and explanation

Net input is 12 m³/day, so storage gains 60 m³ and reaches 310 m³. Lake area/shape or a volume-level relationship is needed for height change.

Subtract 40−28 = 12 m³/day.

Multiply by five days to obtain 60 m³ and add to 250.

Distinguish volume from height and request geometry.

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.

Problem 12

Which provides a major source of energy for atmospheric circulation?
  1. Unequal absorption of sunlight
  2. Destruction of air molecules
  3. Earth’s map grid
  4. Magnetic north alone
Answer and explanation

Unequal absorption of sunlight

Unequal heating creates conditions that drive circulation.

Problem 13

Connect evaporation and condensation to energy transfer.
Answer and explanation

Evaporation absorbs energy where it occurs; condensation releases energy elsewhere, transferring energy through the water cycle.

Problem 14

Independent chapter check: 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.

Problem 15

High pressure is generally associated with
  1. rising air and storms
  2. sinking air and settled weather
  3. fronts
  4. rapid pressure change
Answer and explanation

sinking air and settled weather

Sinking air warms and dries, suppressing cloud formation.

Problem 16

Explain why forecasts become less reliable several days ahead.
Answer and explanation

The atmosphere is sensitive to small differences in starting conditions, and measurements are never perfect or complete. Tiny errors grow as a forecast model runs forward, so predictions that are accurate over hours become progressively less certain over days. Forecasters handle this by running many simulations from slightly different starting points and reporting a probability rather than a single outcome.

Response criteria

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

Problem 17

Independent chapter check: Two maps have the same ground scale. Map A shows a 4 hPa change over 100 km; map B a 2 hPa change over 25 km. Compare pressure-gradient magnitudes and explain why neither gives a full wind direction alone.
Answer and explanation

A is 0.04 hPa/km; B is 0.08 hPa/km, twice as large. Actual wind also responds to rotation and friction, so pressure-gradient magnitude alone is not a complete directional forecast.

Calculate 4/100 and 2/25 in matched units.

Compare 0.08 with 0.04: factor two.

Include rotation/friction and distinguish pressure-gradient force from wind.

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.

Problem 18

To forecast tomorrow's weather for a mid-latitude town, the most useful information is conditions
  1. directly overhead now
  2. to the west now
  3. to the east now
  4. last month
Answer and explanation

to the west now

Systems generally travel west to east, so upstream conditions arrive next.

Problem 19

Explain how a forecaster uses a pressure map and an air-mass map together.
Answer and explanation

The pressure map shows where systems are, how intense they are and which way the wind will blow, with closely spaced isobars indicating strong winds. The air-mass map says what kind of air each system is carrying — warm and moist, or cold and dry. Combining them predicts not just that a system is coming but what weather it will bring when it arrives, which neither map gives alone.

Response criteria

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

Problem 20

Independent chapter check: A front is 90 km from a town. Model A gives steady motion 30 km/h and model B 45 km/h. Calculate the two arrival times and define a fair observation-based timing check.
Answer and explanation

A gives 3 h and B 2 h. Record the forecast issue time, defined passage indicator/location and predicted intervals, then compare with later observations using the original criteria. Changing criteria after the event undermines verification.

A gives 3 h and B 2 h. Record the forecast issue time, defined passage indicator/location and predicted intervals, then compare with later observations using the original criteria. Changing criteria after the event undermines verification.

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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