Where can water go?
A model helps us explain where water can move, including changes we cannot directly see.
Pause: Predict a route. What can this model show, and what might it leave out?

Liquid water becomes invisible vapor
Energy from the Sun supports evaporation. Liquid water becomes water vapor in the air. Water vapor is invisible. Evaporation can also happen without direct sunlight.
Pause: Has the water stopped existing? Explain your reasoning.

Cooling can form tiny droplets
When water vapor cools, it can condense into tiny liquid droplets. Clouds contain tiny droplets, ice crystals, or both. The visible cloud is different from invisible water vapor.
Pause: Explain why a visible cloud is not a cloud of visible water vapor.

Gravity helps water move downward
Gravity helps water fall as precipitation and move downhill. Some water runs over the surface. Some enters the ground. These are possible routes, not one required sequence.
Pause: Which arrows show water moving because of gravity?

Water can travel through plants
Plants take up water through their roots and release water vapor from their leaves through transpiration. Water can travel along different routes.
Pause: Trace a route that returns water to the air without visiting the ocean.

Water can remain in storage
Water can remain in storage, including underground. It does not all move around one loop at the same speed. This model does not show quantities or real travel times.
Pause: What does a single circular arrow hide?

Explain your model
Use evidence to support, extend, or revise your model. Explain a possible route and a limitation. Pause here to respond to the question.
Pause: Use evidence to support, extend, or revise your earlier model. Show two possible water routes. Explain one energy transfer and one role of gravity, then state a limitation of your model.