Chapter 2 Recognizing Energy Transfer Objective recognize that

Chapter 2: Recognizing Energy Transfer Objective: recognize that energy moves from place to place and changes forms to make things happen

Energy Transfers • The movement of energy – Every time something happens energy is involved – Movement of energy from one object to another, one form to another, and one place to another causes a change

Energy Transfers and the Natural World • Energy transfers from the sun – Earth receives a steady supply of energy from the sun, the source of all weather • Clouds and Precipitation – Heats water which evaporates, cools and condenses to form clouds, then falls as precipitation (water cycle) • Wind – Sun does not heat the Earth equally v Uneven heating causes wind • Storms – Come from transfer of sun’s energy to the Earth v Forms hurricanes- see p. 15

Photosynthesis • The transfer of energy from the sun feeds plants – Almost all living things depend on food created by green plants • Have special colored substance that catches the sun’s energy – Use this light energy to create food (chemical energy) v Called Photosynthesis v plants use food to grow and when animals eat the plants, the energy transfers to them

Energy Transfers from Inside the Earth • Energy also comes from the Earth’s center (4300 C to 7200 C) – Causes changes on surface like earthquakes and volcanic eruptions • Heat energy from deep in the earth is being transferred to motion energy

Heat Transfer from Earth’s Core • Cause of Earthquakes – Core- center of the earth is very hot – Heat energy is transferred from core out towards surface • Heat makes mantle so hot that it can flow slowly • The earth’s crust rests on the mantle – As the mantle flows, the crust shifts causing an earthquake • Cause of Volcanic Eruption – Heat from core is transferred to rock under the earth’s surface • The rock melts, and sometimes escapes through cracks

Energy Transferred Between Living Things • Some energy transfers happen so slowly, or on such a small scale, it is hard to see them at all – Decomposing log • Chemical energy transfers to living organisms feeding on it – Mushrooms, bacteria, and worms v A large log can take decades

The Food Chain • Energy transferred between living things – Food chains show energy is passed from one organism to another • See p. 20 for an example

Frequently Asked Questions • Does energy change when it is transferred? – Sometimes it does • Sun light (light energy) to plant (chemical energy) – Sometimes it does not • Spoon put in hot liquid – Heat travels up through spoon • How can I tell that energy is being transferred in the natural world? – Where ever there is change • seasons change, earth changes, living things change