Science Study Guide: Chapter 1

What is the relationship between density, pressure and altitude?

All properties of air.

Name two ways carbon dioxide is added to the atmosphere.

Animals put out carbon dioxide as a waste product when breathing. When fuels such as coal and gasoline are burned, they release carbon dioxide.

Why do you get out of breathe easily at the top of a mountain?

As you go up through the atmosphere, the air pressure decreases. As air pressure decreases, the density of the air decreases. So density decreases as altitude increases. It doesn't matter at what altitude you are at; the air still contains 21% oxygen. However, since the air is less dense at a high altitude, there are fewer oxygen molecules to breathe in each cubic meter of air than there are at sea level. You are taking in less oxygen with each breath.

Why is the atmosphere important to living things?

Earth's atmosphere makes conditions on Earth suitable for living things. It contains oxygen and other gases we need. It traps the sun's energy and allows water to exist as a liquid. It also protects us from being hit by most meteoroids.

What might conditions on Earth be like without the greenhouse effect?

Earth's temperature would be around -18 °C. All water on Earth would freeze. The oceans would turn to ice. Life would not be able to exist.

What is Global Warming? What gas is the cause of Global Warming?

Global warming is the gradual increase in the temperature of Earth's atmosphere. Human activities are adding greenhouse gases into the atmosphere like Carbon Dioxide. We burn fossil fuels everyday and it adds to the Carbon Dioxide already in the atmosphere.

What is the greenhouse effect?

In Earth's atmosphere, there are gases. These gases are Methane, Carbon Dioxide, and Nitrous Oxide. These gases are also known as greenhouse gases. These gases warm up our atmosphere through a process called the greenhouse effect. The greenhouse effect occurs when sunlight strikes the Earth. Some of the light is reflected and some of it is absorbed. The absorbed light warms the surface of the Earth. The heated surface then radiates infrared light into the atmosphere where it is absorbed by the greenhouse gases. These gases help regulate the temperature of Earth. Due to the burning of large amounts of fossil fuels (coal, oil, natural gas), the amount of greenhouse gases in the atmosphere has dramatically increased (burning fossil fuels releases Carbon Dioxide). Trees help remove Carbon Dioxide as part of a process between humans and plants (breathing). People are cutting down trees and as a result, staggering amounts of Carbon Dioxide is in the atmosphere. This is resulting in an increase in Earth's surface temperature.

List the 4 main atmospheric gases and their percents'.

Nitrogen (78%), Oxygen (21%), Carbon Dioxide (0.036%), and Argon (0.93%). Water vapor also exists in our atmosphere.

Know the characteristic scientists use to classify the atmosphere into layers.

The four main layers of the atmosphere are classified according to changes in temperature.

How does the ozone layer help life on earth?

The ozone absorbs energy from the sun and the energy is converted into heat, warming the air.

What is air pressure?

The result of the weight of a column of air pushing down on an area.

List the 4 main layers and describe one characteristic of each of the four main layers of the atmosphere.

Troposphere: Earth's weather occurs here. Stratosphere: The ozone layer in the stratosphere absorbs ultraviolet radiation. Mesosphere: Most meteoroids burn up in the mesosphere, producing meteor trails. Thermosphere: Nitrogen and oxygen molecules in the thermosphere convert energy from the sun into heat. This is why it is extremely hot in the thermosphere.

Why is water vapor considered the most variable?

Water vapor varies from place to place and from time to time. It plays an important role in Earth's weather.

How would a barometer change if it were carried down a mineshaft?

A barometer is an instrument that is used to measure changes in air pressure. If you are going down a mineshaft, it is going below sea level. The pressure would increase. With a mercury barometer, the mercury would increase higher the further you go down.