Chapter 2; Section 2 Atmospheric Heating Heat transfer

THINK ABOUT IT… If you add ice to lemonade on a hot summer’s day why does the ice melt? Choose the best answer: A. The coldness from the ice moved into the lemonade B. The heat from the lemonade moved into the ice C. The coldness and heat moved back and forth until the lemonade cooled off

The correct answer is B. The heat from the lemonade moved into the ice. Heat energy is transferred from one place to another through the process of heat flow. This thermal energy will only move from a warmer object to a cooler object, never the other way around. Heat went into the ice from the lemonade, cooling the lemonade and melting the ice

Heat can be transferred in 3 ways:

Radiation: Solar Energy Transfers by Waves Radiation: is energy that is transferred as electromagnetic waves, such as visible light and infrared waves. Examples include visible light, radio waves, and radiant heat. Can be in the form of particles or waves.

Examples of radiation (heat)

Conduction Solar Energy Transfers by Contact The direct transfer of heat from one substance to another substance that is touching it. Molecules can pass heat energy to adjacent molecules, heating them as well Conduction works better in certain substances, like metals

Examples of conduction

The transfer of heat by a liquid or gas (such as air). Convection The transfer of heat by a liquid or gas (such as air). Can only occur in liquids and gases (relatively big spaces between the molecules) A convection current is where hot air rises and cold air sinks.

Examples of convection

All 3 types work together:

Green house effect Green house effect- Is a natural process that permits the Earth to retain some of the heat from the sun. This process functions like the glass of a greenhouse, allows solar energy to enter but prevents it from escaping. Without the greenhouse effect the earth would be cold as Mars! But too much Greenhouse gases can heat up the Earth too fast: Rising seas, Polar ice melting, Unpredictable storms

Green house gases Gases in the atmosphere (water vapor, carbon dioxide, nitrous oxide, and methane) trap energy from the sun.

Global warming The gradual increase in average global temperatures Data shows that the average global temperatures have increased in the past 100 years. Scientists hypothesize that greenhouse gases may be the cause.

Heating in the troposphere Convection causes most of the heating of the troposphere Air near the ground is heated by the sun (radiation) The molecules gain energy and move faster As they bump into each other they move further apart and become less dense The less dense air then rises due to the warm temperature Cooler, denser air sinks This causes a constant movement of heat through the troposphere called convection current!!

Radiation Direct transfer of energy without heating the space in between Fireplace Microwave Radiator Energy from the Sun to the Earth

Convection Transfer of a heat through a fluid (gas or liquid) Oven Boiling Water Air rising (hot) and falling (cold

Conduction Transfer of heat from one substance to another that is touching Hair Straightener Heating Pad Electric Blanket Energy from molecules that touch Earth’s surface