Chapter 7
* All the waters of the Earth make up the hydrosphere
* The oceans cover 75 percent of the Earth.
* Currents carry warm water toward the poles.
* Cold water with high salinity is heavier than warm water with low salinity.
* Rivers, streams, and lakes are surface freshwater.
* Icebergs form when a large piece of ice breaks off a glacier or ice sheet.
* Water that fills spaces between particles of rock and soil is groundwater.
* The top level of groundwater in an aquifer is called the water table.
* Condensation is when water vapor changes into liquid
* During condensation, dew forms.
* Water vapor on a surface may freeze without becoming liquid water first. This is called frost.
* Many clouds in the summer sky are made of ice crystals.
* Sleet is frozen raindrops falling from clouds.
* Clouds form when water vapor changes into tiny water droplets or ice crystals. Clouds often
form when air moves upward to areas of less air pressure.
* There are two ways water is treated before it comes into your home.
* 1) It passes through filters that remove small particles.
2) Many communities add chlorine to kill bacteria and fluoride to help your teeth.
* Evaporation and sublimation both occur during the water cycle. During both, water vapor is
formed. During evaporation, liquid water turns into water vapor. During sublimation, ice turns
directly into water vapor, without turning into liquid water first. Sublimation is much slower than
evaporation.
* Be able to identify and describe the different types of clouds
1. Vertical clouds grow vertically because they have rising air inside them. This air pushes the
tops of the clouds higher. They are sometimes called thunderheads.
2. Altocumulous clouds are mid-altitude clouds that look like small puffy balls. The bottoms
can look dark because sunlight cannot reach them.
3. Stratus clouds are low altitude clouds that are often seen less than 2000 m above the
ground. They cover the whole sky and can look dark because sunlight cannot get through
the layers of clouds.
4. Cirrus clouds are high-altitude clouds that are thin wispy and white. They form at an altitude
of more than 6000m
* Fog is a cloud at ground level.
* Rain, snow, sleet and hail are types of precipitation
* The layer of rock and soil that groundwater flows through is an aquifer.
* Sublimation is the process of ice turning directly from a solid to a gas.
* Salinity is a measure of how salty water is.
* A reservoir is a lake that forms behind a dam.
* Hail forms when strong winds toss ice crystals up and down in a cloud.
* Some examples of evaporation are
* Clouds are made of water droplets or ice crystals.
* Clouds fall in winter and not summer because in the summer, the temperature of air near the
ground is warmer than 0°C. Ice crystals that fall from clouds melt and become rain before they
reach the ground. In winter, the temperature of air near the ground is colder. Thus, ice crystals
may not get warm enough to melt.
* Water as a solid is ice, water as a liquid is water, and water as a gas is water vapor.
* Snowflakes fall in the winter and not in the summer because the temperature of air near the
ground is warmer than 0°C.
* Some currents carry warm water toward the poles, such as the Gulf Stream
* Some currents carry cold water toward the equator
* Much of the salt we add to our food comes from the ocean