Goal 2 – Students will explain how energy is transferred in the atmosphere.

What is Weather?

• Energy is transferred between fast-moving molecules and slower-moving molecules–CONDUCTION – transfer of energy when

molecules collide (Touching a hot plate)–CONVECTION – occurs when warm air rises

and cool air sinks; it’s the transfer of heat, usually in liquids or gases (Lava lamp)–RADIATION - energy transferred in rays or

waves (Sun)

If we were to pick one term to help explain why we have weather, what do

you think would be a good word?

You might pick heat or sun….but another good

choice would be

Convection

After the atmosphere is warmed by radiation and conduction, the heat is transferred

throughout the atmosphere by convection.

• Since warmed air has more space between the molecules, it’s less dense and rises

• Cooled air is more dense and tends to sink

• In general, air near the equator tends to rise and air near the poles tends to sink

Homework

Find and describe 3 examples of energy transfer in your home. Write it out on your own sheet of lined notebook paper. Draw a picture of how the energy is being transferred.

YES, THIS WILL BE A GRADE!!

In the picture to the right, some workers are trying to reconnect two rails that have separated due to the extreme cold. To fix the problem, the workers have lit an oil-soaked rope that lies next to the track. The heat of the fire will cause the tracks to expand so that they can be reconnected once again.

Gases expand when heated and contract when cooled. For instance, a balloon will expand if it is left in a hot car. It will get smaller if it is put in the refrigerator.

Liquids expand when heated and they contract when cooled. Think about mercury in a thermometer! Ice however, expands when it freezes. This is why we have potholes!!

• The water cycle—water moves back and forth between Earth's atmosphere and surface

• http://www.crickweb.co.uk/assets/resources/flash.php?&file=watercycle

• Energy from the Sun causes water to evaporate from the hydrosphere, and rise as vapor.

• Water vapor in the atmosphere can cool and return to liquid form through condensation.

• a. When water vapor condenses, clouds of tiny water droplets may form.

• b. Water droplets collide to form larger precipitation

Precipitation