GED Science
Weather, Climate & the Water Cycle
Weather is what the sky does today; climate is what it usually does over decades. Underneath both runs the water cycle — the sun endlessly lifting water up and gravity bringing it back down. Most questions are either the weather/climate distinction or one loop of the cycle.
The words first
- weather vs climate
- today's conditions vs the 30-year average pattern
- evaporation / condensation / precipitation
- liquid → vapor / vapor → droplets (clouds) / droplets falling
- humidity
- how much water vapor the air holds
- front
- a boundary where two air masses meet — where weather happens
The method
THE WATER CYCLE LOOP
sun heats ocean → EVAPORATION (liquid → vapor)
vapor rises, cools → CONDENSATION (vapor → cloud droplets)
droplets merge, get heavy → PRECIPITATION (rain, snow)
water flows back → RUNOFF and groundwater → ocean → repeat
The engine is the SUN; the return trip is GRAVITY.
WEATHER vs CLIMATE — the wardrobe rule
weather picks today's outfit;
climate fills your closet.
"It snowed Tuesday" → weather
"Winters here average −5°" → climate
FRONTS
cold front: cold air shoves under warm → quick storms, then clear
warm front: warm air slides over cold → long, steady rain
AIR PRESSURE
HIGH pressure → sinking air → clear skies
LOW pressure → rising air → clouds and storms
Worked all the way through
The problem
A puddle disappears by noon; that evening, dew coats the grass. Name the two water-cycle processes and what drove each.
- Step 1 — The vanishing puddle.Liquid water became vapor: evaporation, driven by the sun's heat.
- Step 2 — The evening dew.Air cooled after sunset; its vapor turned back to liquid on the cold grass: condensation, driven by cooling.
- Step 3 — Note the symmetry.Same water, opposite direction: heat sends it up, cooling brings it back.
On the board
puddle → vapor
evaporation (sun's heat)
night air cools
vapor → droplets on grass
condensation (cooling)
heat up, cool down — one cycle
Answer
Evaporation (daytime heating), then condensation (nighttime cooling)
A second one, in a different form
"Phoenix hit 95° today" and "Phoenix summers average over 100°." Which is weather, which is climate?
today's number
one day → weather
the summer average
long-term pattern → climate
one hot day proves nothing about climate
and vice versa
Answer
95° today = weather; the long-run average = climate
The usual mistake
Swapping evaporation and condensation. Evaporation needs heat added.
Check yourself
Check the time span before answering: one day or one storm is weather, a multi-decade average is climate. And in cycle questions, name the driver — heat for the trip up, cooling and gravity for the trip down.
Practice it
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