1. U1L2&3 – The Water Cycle, Surface Water and Groundwater
8th Grade Water & Atmosphere (Mod F)
U1L2&3 – The Water Cycle, Surface Water and Groundwater
Water gets into the atmosphere in three ways:
1. evaporation
liquid water turns into water vapor (gas)
90% of water in atmosphere comes from this (mostly from oceans)
2. transpiration
Plants release water vapor through stomata (tiny pores on leaves)
About 10% comes from this
3. sublimation
Solid water (ice) turns directly into gas (water vapor)
Where dry, cold air blows over ice & snow
Very small amount

2. Water in the atmosphere does 2 things 1. condensation
When temperatures lower, water vapor condenses on small particles like dust or pollen in air
If drops are too small to fall, they stay as clouds
2. precipitation
When droplets get too big to stay in clouds, they fall out
Rain, snow, hail, etc.

3. Water moves on land & in oceans
1. Runoff: streams, rivers & other water that flows over earth’s surface because of gravity
2. Infiltration: water on land seeps into the ground
Groundwater – water under the ground!
3. Ice flow: glaciers “rivers of ice” flow because of gravity
4. Ocean circulation: ocean currents can move water thousands of miles
Surface currents and deep ocean currents

4. ENERGY is transported in the water cycle
MATTER is transported in the water cycle
Read p. 21
Water (like all matter) is not created or destroyed, it only changes form!