Question

activity (continued from previous page)

1. define: a phase change is a change from one state to another, such as from a liquid to a gas. based on what you have read in the gizmo, fill in the blanks with the words liquid, gas, orsolid to define each change.

evaporation: change from a __________ to a __________
condensation: change from a __________ to a __________
melting: change from a __________ to a __________
freezing: change from a __________ to a __________

1. practice: fill in the process that causes each transition. your choices are evaporation, condensation, precipitation, melting, and freezing.

a. ocean → atmosphere ____________
b. atmosphere → clouds ____________
c. cloud → snow ____________
d. glacier (river of ice) → river ____________
e. cloud → soil ____________

1. practice: fill in the two processes that cause each of the following transitions.

a. ocean → cloud __________, __________
b. cloud → glacier __________, __________

1. think and discuss: water covers over two - thirds of earth’s surface. yet water shortages are a major problem for many people around the world. why do you think this is the case?

Explanation:

Step1: Define evaporation

Evaporation is the change of a liquid to a gas.

Step2: Define condensation

Condensation is the change of a gas to a liquid.

Step3: Define melting

Melting is the change of a solid to a liquid.

Step4: Define freezing

Freezing is the change of a liquid to a solid.

Step5: Analyze transition from ocean to atmosphere

Ocean is liquid water, atmosphere has water - vapor (gas). The process is evaporation.

Step6: Analyze transition from atmosphere to clouds

Water - vapor (gas) in atmosphere forms liquid droplets in clouds. The process is condensation.

Step7: Analyze transition from cloud to snow

Clouds have water - vapor or liquid droplets, snow is solid. The process is precipitation (in the form of snow).

Step8: Analyze transition from glacier to river

Glacier is solid ice, river is liquid water. The process is melting.

Step9: Analyze transition from cloud to soil

Clouds release water as rain (precipitation) which can reach the soil.

Step10: Analyze transition from ocean to cloud

Water evaporates from the ocean to form water - vapor in the atmosphere, then condenses to form clouds. So the processes are evaporation and condensation.

Step11: Analyze transition from cloud to glacier

Water in clouds precipitates as snow, which accumulates and compresses over time to form a glacier. So the processes are precipitation and freezing.

Step12: Analyze water shortage problem

Most of Earth's water is salt - water in oceans, not suitable for direct human use. Freshwater is limited and unevenly distributed. Also, pollution can make freshwater sources unusable.

Answer:

3.
Evaporation: Change from a liquid to a gas
Condensation: Change from a gas to a liquid
Melting: Change from a solid to a liquid
Freezing: Change from a liquid to a solid
4.
A. Evaporation
B. Condensation
C. Precipitation
D. Melting
E. Precipitation
5.
A. Evaporation, Condensation
B. Precipitation, Freezing

1. Most of Earth's water is salt - water in oceans. Freshwater is limited and unevenly distributed, and pollution can contaminate freshwater sources.