Transcript Chapter 2: Recognizing Energy Transfer

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
 Uneven heating causes wind
• Storms
– Come from transfer of sun’s energy to the Earth
 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)
 Called Photosynthesis
 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
 A large log can take decades
The Food Chain
• Energy transferred between living things
– Food chains show how 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