13.2 Radiation, Conduction & Convection

Before you learned The atmosphere supports and protects life The atmosphere supports and protects life The atmosphere contains a mixture of gasses. The atmosphere contains a mixture of gasses. 78% Nitrogen 78% Nitrogen 21% Oxygen 21% Oxygen 1% Other gasses 1% Other gasses The atmosphere is affected by natural processes. The atmosphere is affected by natural processes.

Now we will learn how Solar energy heats earth’s surface and atmosphere. Solar energy heats earth’s surface and atmosphere. The atmosphere moves heat energy around. The atmosphere moves heat energy around. The layers of the atmosphere play a role in the movement of energy. The layers of the atmosphere play a role in the movement of energy.

13.2 Key Terms Radiation Radiation Energy that travels distances in the form of waves. This can include solar radiation like UV radiation and visible light. Energy that travels distances in the form of waves. This can include solar radiation like UV radiation and visible light. Conduction Conduction This is the transfer of heat based on direct contact. You walk on a hot sidewalk or touch a hot piece of metal. This is the transfer of heat based on direct contact. You walk on a hot sidewalk or touch a hot piece of metal.

13.2 Key Terms Convection Convection This is the transfer of heat energy from place to place by the motion of a gas or a liquid. Think about pouring a hot liquid into a cold one, or feeling the heat rising off of a fire. This is the transfer of heat energy from place to place by the motion of a gas or a liquid. Think about pouring a hot liquid into a cold one, or feeling the heat rising off of a fire.

Radiation Radiation is not always a bad thing! Radiation is not always a bad thing! Solar radiation constantly is bombarding earth. Without it, we would not be able to live. Solar radiation constantly is bombarding earth. Without it, we would not be able to live. Solar radiation provides us with light and heat. Solar radiation provides us with light and heat. However, not all of the radiation from the sun reaches our planet’s surface. However, not all of the radiation from the sun reaches our planet’s surface.

Radiation and Earth Of the 100% of solar energy that reaches our planet, only about 70% is actually absorbed. Here’s the breakdown; Of the 100% of solar energy that reaches our planet, only about 70% is actually absorbed. Here’s the breakdown; 70% absorption 70% absorption 40-45% absorbed by Earth’s surface % absorbed by Earth’s surface. This radiation can be released as heat from Earth’s surface, be used to evaporate water, or to create wind. This radiation can be released as heat from Earth’s surface, be used to evaporate water, or to create wind % absorbed by Earth’s atmosphere % absorbed by Earth’s atmosphere.

Radiation and Earth 30% Reflection 30% Reflection 25% by clouds in the atmosphere 25% by clouds in the atmosphere 5% by surface objects such as glass & metal buildings, ice and snow. 5% by surface objects such as glass & metal buildings, ice and snow.

Solar Energy and Earth’s Atmosphere

The atmosphere moves energy It does this through 3 actions It does this through 3 actions Radiation Radiation Conduction Conduction Convection Convection

Radiation and the atmosphere The atmosphere as we have already pointed out, is capable of absorbing some heat from the sun. The atmosphere as we have already pointed out, is capable of absorbing some heat from the sun. It absorbs a special kind of energy called infrared energy. It absorbs a special kind of energy called infrared energy.

Conduction & the atmosphere Conduction is the transfer of energy based on direct contact. Conduction is the transfer of energy based on direct contact. When you walk along a hot beach, the heated atoms in the sand are making contact with the atoms in your foot. They transfer energy to your foot and your foot gets hot. When you walk along a hot beach, the heated atoms in the sand are making contact with the atoms in your foot. They transfer energy to your foot and your foot gets hot.

Conduction & the atmosphere The atmosphere can be heated by conduction. You have seen this (and convection too) if you’ve ever seen air shimmering and waving over a parking lot on a hot summers day. The atmosphere can be heated by conduction. You have seen this (and convection too) if you’ve ever seen air shimmering and waving over a parking lot on a hot summers day. This transfer of heat by direct contact causes the air to rise, and cool air rushes in below to take its place. This transfer of heat by direct contact causes the air to rise, and cool air rushes in below to take its place.

Convection and the atmosphere Convection is the movement of air through the atmosphere. Convection is the movement of air through the atmosphere. The air movement is driven by energy gained from radiation or conduction. The air movement is driven by energy gained from radiation or conduction. As the air gains energy, the atoms move more, spreading out. As the air gains energy, the atoms move more, spreading out. As they spread out, they become less dense, and are squeezed up by colder, more dense air trying to get under it. As they spread out, they become less dense, and are squeezed up by colder, more dense air trying to get under it.

Convection and the atmosphere

Density and the atmosphere Differences in density are what drive the movement. Differences in density are what drive the movement. The differences in density are caused by solar energy however. The differences in density are caused by solar energy however.