Unit 1, Chapter 1 Reading Checks
Lyndon Cobb
Reading Check – Page 17
1. What is salinity?
salinity [suh-LIN-i-tee] the amount of salt dissolved in a specific amount of water (1.2)
2. Why is ocean water saltier near the equator?
Close to the equator, the salinity is high because of high rates of evaporation. When the water in the
ocean transforms into vapour in the air, it leaves the salt behind.
Water is very salty near the North and South Poles as well because when water freezes and changes
into ice, it also leaves the salt behind.
3. Name two sources of ocean salt.
a. when the rain falls on the land, most of it seeps into the ground, and then eventually into
streams and rivers. From there it travels to the ocean. Moving over and through the round,
the water picks up materials from the rocks. These materials are called dissolved solids, and
you cannot see them even with the help of a microscope. They get carried by the water from
the land and into the ocean (Figure 1.6).
b. Volcanoes contribute some chemicals as well. Undersea volcanic eruptions from the sea floor
release large amounts of sulphur, fluorine, chlorine, and hydrogen into ocean water. Eruptions
on land spew similar materials high into the atmosphere. These materials then fall directly
into the ocean, or onto Earth’s surface from where they get carried to the ocean as run-off.
4. What is density?
Density is the amount of mass of a substance in a certain unit volume.
5. Why is ocean water more dense than fresh water?
Because of the amount of salt in it, ocean water is denser than fresh water.
Reading Check – Page 24
1. Name four sources of fresh water on Earth.
The fresh water that is available is found wherever water falling as rain and snow runs off the land
and is collected in lakes, rivers, streams, and underground.
2. What is groundwater?
ground water precipitation that falls on land and sinks out of sight and remains in cracks underground
(1.3)
3. How is a glacier formed?
When snow doesn’t melt, it begins piling up. As it accumulates, the weight of the now becomes great
enough to compress the bottom layers into ice. Eventually, the snow can pile so high that the pressure on the
ice on the bottom causes partial melting. Then, the ice and snow begin to slide downhill. This moving mass of ice
and snow is called a glacier.
4. When did the last ice age end?
The most recent ice age began about 120 000 years ago, and ended only 11 000 years ago.
5. How is global warming affecting glaciers?
In the last 100 years, the average surface temperature on Earth has increased 0.5°C. Although that
may not seem like very much, it is enough to have an effect on the glaciers and polar ice caps. Most glaciers in
the world today are receding, meaning that they are melting and shrinking.
Reading Check – Page 28
Page 1 of 2
Unit 1, Chapter 1 Reading Checks
Lyndon Cobb
1. What is a drainage basin?
A drainage basin, or watershed, is the area of land that drains into a body of water, such as a river,
pond, lake, or ocean.
2. What is the Continental Divide?
These mountains form the Continental Divide that separates the Pacific drainage basin from drainage
basins to the east of the Rocky Mountains (Figure 1.16)
3. Explain what run-off is.
run-off precipitation that falls to land and flows into creeks, streams, and rivers and eventually into
the ocean (1.3)
4. What force pulls run-off to the lowest possible point?
The force pulling it down to the lowest point is gravity, the same force that keeps us on the ground.
5. Name four factors that affect run-off.
a. The nature of the ground material:
b. The amount of rain:
c. The length of time it rains:
d. The slope of the land:
e. The amount of vegetation:
f. The amount of development in the area:
Page 2 of 2