Thermal Energy (Heat)
- Infrared Radiation from the Sun is absorbed by the Earth and released as heat
- Heat Energy makes molecules move
- Temperature is the measurement of the motion of molecules
- Transferred from a HOTTER surface to a COLDER surface
Thermal Energy Transfer
- transferred in 3 ways: radiation, conduction, and convection
- RADIATION: direct transfer of energy from the Sun, travels in electromagnetic waves (infrared radiation), transferred to heat energy
- CONDUCTION: it is the transfer of heat energy through direct contact EX: bare feet on the concrete
- Solids conduct more heat while liquids conduct less heat
- Air is a poor conductor
- CONVECTION: it is the transfer of heat by the movement of molecules in liquids and gases, warm air rises and cold air sinks
Hot VS Cold
In a lava lamp, the heat gets transferred from the heat source (the outlet) to the lava through conduction. It is transferred through conduction because the heat source is touching the vase which is touching the lava. The, the hot lava rises and the cooler lava sinks which is convection. Convection is the movement of fluids. |
•Infrared radiation from the Sun is absorbed by the surface
•Surface converts infrared radiation into thermal energy
•Thermal energy heats up the air at the surface causing temperature
•Warm air is less dense than cold air. Since air is a fluid the warm air is pushed up by the cold air.
•Convection, warm air to rises and cold air to sinks, which makes a cycle
•When warm air rises it creates a low pressure area
•When cool air sinks it creates a high pressure area
•Air will be pushed away from the high pressure area to the low pressure area
•Surface converts infrared radiation into thermal energy
•Thermal energy heats up the air at the surface causing temperature
•Warm air is less dense than cold air. Since air is a fluid the warm air is pushed up by the cold air.
•Convection, warm air to rises and cold air to sinks, which makes a cycle
•When warm air rises it creates a low pressure area
•When cool air sinks it creates a high pressure area
•Air will be pushed away from the high pressure area to the low pressure area
Winds
•The horizontal movement of air is called wind.
Winds can be local or cover large areas of land
Winds can be local or cover large areas of land
Global Winds
The air around the equator is heated the most
It starts raising up through the troposphere
When it hits the top of the troposphere it moves laterally (north and south)
It starts raising up through the troposphere
When it hits the top of the troposphere it moves laterally (north and south)
Prevailing Winds
- winds above the surface of Earth that flow in a specific direction all year round
- Northern Hemisphere:Jet Streams are fast-moving, narrow bands of air that circle the Earth
- A jet stream is usually about 11 km above the Earth
Coriolis Effect
- The force due to the Earth's rotation that causes objects in motion to veer right in the Northern Hemisphere and to the left in the Southern Hemisphere.
Anemometer
- An instrument for measuring the speed of wind
- measures the wind speed from the speed of rotation of a windmill which consist of 3 or 4 conical cups, each fixed to the ends of horizontal arms attached to a vertical axis
Ocean Currents
- Ocean water contains stream like movements of water called ocean currents
- Currents are created by global winds, salinity, and convection.
- Currents are driven by the Earth’s rotation and continental deflection.
- Current Move:
Clockwise in the northern hemisphere
Counterclockwise in the southern hemisphere
Convection Cells Cause Currents
- Sun’s energy causes convective movement of the ocean’s water
- Heat from the sun causes differences in the density of the water
Global Winds Cause Ocean Currents
- Winds low across the Earth’s surface creating surface currents that can reach depths of several hundred meters
- Different winds cause currents to flow in different directions
Salinity Causes Deep Water Ocean Currents
- Powered by temperature, density and salinity
- Cooler saltier water is more dense causing it to sink
- The water is then pushed around the globe until it warms up
Earth's Rotation Drives Currents
- The earth’s rotation causes surface currents to move in curved paths rather than in straight lines
- Ocean current in the Northern hemisphere turn clockwise while ocean currents in the Southern Hemisphere turn counterclockwise
Continental Deflections Drives Currents
- If the Earth’s surface were covered only with water, surface currents would travel freely in a uniform pattern
- When surface currents meet continents, they deflect, or change direction