Energy in Earth’s Processes Unit 5

Introduction  Energy is the ability to do work.  Everything in the universe involves the use or transfer of energy.

Electromagnetic Energy  Energy given off by all matter not at absolute zero.  Absolute zero- lowest possible temperature.

Characteristics  Wavelength- distance from one crest to the next.  Visible light is the only form the human eye can see.  Electromagnetic E can be separated into two groups: long-wave and short-wave * visible light is the “middle”

E. E and the Environment  5 things can happen when energy hits an object: 1.Refracted- bent as it passes through. 2.Reflected- bounces off. 3.Scattered- refracted or reflected in all directions. 4.Transmitted- passed through the material. 5.Absorbed- taken into the material.

Absorbtion  Surface characteristics determine amount of E E that can be absorbed.  Darker surfaces can absorb more E.  Rougher surfaces absorb more E.  The more effective a material is at absorbing E E, the better it is at radiating it.

Transfer of E  E moves from areas of High concentration to L concentration.  Areas of highs are called sources. Areas of lows are called sinks.  Thermal E- energy of the motions of atoms and molecules.  Dynamic Equilibrium- a region loses and gains equal amounts of energy.

Methods of Transfer  3 ways: 1.Conduction- E is transferred from one molecule to another when they vibrate. 2.Convection- E is transferred by movement in fluids. 3.Radiation- E is transferred by electromagnetic waves.

Mechanical E  All the E of an object not related to the individual movements of the atoms and molecules.  Kinetic E- an object in motion.  Potential E- “stored E”. The more mass that is involved, the more potential E.  Potential E can be transformed into kinetic E.

Transformation of Electromag. Wavelength  When E E is abosorbed and re-radiated the wavelength is longer than when it was absorbed.

Temperature and Heat  Temperature of an object or region is directly related to the amount heat, or thermal E in the object or region.  Temperature- the measure of the average kinetic E of the particles of a body of matter.

Heat and Thermal E  When one object has a higher temp. than another, some of the E will be transferred to the cooler object.  The amount of E transferred is measured in calories.  Calorie- amount of heat needed to raise the temp. of one gram of water one degree Celsius.

Specific Heat  The amount of energy it takes to bring any object up one degree Celsius. -ex. Specific heat of H2O is 1 -Specific heat of a certain rock is 0.2 Specific heat is the resistance of an object to heat up or cool down.

Heat E and the States of Matter  An increase or decrease in the amount of E can cause matter to change states.  Melting- from solid to liquid  Solidification or freezing- liquid to solid  Evaporation- liquid to a gas  Condensation- gas to a liquid  Sublimation- gas directly to a solid or from a solid to a gas.

Earth’s E Supply  Some comes from Earth’s interior  Most comes from the sun

Solar E  Sun gives off all kinds of EE  Greatest intensity is visible light.  Nuclear Fusion

Earth’s E  Most E comes from the nuclear decay of radioactive materials.