Sun Notes

Starter If it is summer in the northern hemisphere, which statement is true? A.Earth has changed the tilt of its axis by 20 degrees due to its revolution. B.It is winter in the southern hemisphere due to the tilt of Earth’s axis. C.It is summer in the southern hemisphere due to the tilt of Earth’s axis. D.Earth has reached its closest point to the sun due to its revolution.

The Sun The sun is the source of all energy on Earth. The Sun transfers energy by 1.Radiation 2.Conduction 3.Convection

The Sun  Radiation: transfer of energy through space by light and waves  Conduction: transfer of energy when molecules collide (touch)  Convection: transfer of energy by the flow of a substance (convection currents)

The Sun  Light absorbed by plants is turned into food. This is called photosynthesis. Plants need Water, Carbon Dioxide and light to produce food (glucose) and Oxygen 6H CO 2 light  C 6 H 12 O 6 + 6O 2

THE SUN’S ENERGY  Nuclear Fission  Splitting of large-nuclei elements, such as uranium or plutonium, into smaller pieces with the release of considerable energy.  Used on Earth to produce electricity in nuclear power plants and to make atomic weapons.  Nuclear fusion  Combining of atomic nuclei into larger nuclei with the release of a very large amount of energy.  Occurs only on the sun  Requires a temperature of tens of millions of degrees C.

How Sun’s Energy is Transferred  Solar radiation is radiant energy emitted by the sun, particularly electromagnetic energy.  Conduction occurs when energy is transferred from earth’s surface air to atmospheric air.  Convection occurs as pockets of air near earth’s surface are heated, become less dense, rise, cool, and sink. Then heated and cycle over again.

How Sun’s Energy is Transferred

Energy from the Sun video  +sun