Aim: What are Earth’s physical properties?. 1. Spherical shape 2. Rotates on an axis ◦ Rotation...

Aim: What are Earth’s physical properties?

1. Spherical shape2. Rotates on an axis◦ Rotation of Earth: causes day and night 1rotation= 1 day

3. Magnetic field◦ North and south pole◦ Protects you from harmful solar

radiation by trapping charged particles from the Sun

Magnetic axis is different from its rotational axis Magnetic axis-the line joining the

north and south poles When you follow a compass you are

following the magnetic axis not rotational axis

1revolution=1year◦Earth’s orbit is an ellipse◦Distance from the Earth to the sun changes

◦Earth is closest to the sun in January

◦Earth is farthest from the Sun in July

Earth’s tilted axis causes seasons

The number of daylight hours is greater for the hemisphere that is tilted towards the Sun◦Winter-hemisphere titled away from the Sun

Less sunlight each day◦Summer-hemisphere titled towards the sun

Longer periods of sunlight each day

Earth’s tilt also causes the Sun’s radiation to hit the Earth at different angles

Summer◦the Sun’s radiation strikes at a higher angle causing it to be hot

Winter◦the hemisphere that is not tilted toward the sun, experiences less radiation

The day when the Sun reaches its greatest distance north or south of the equator

Northern Hemisphere◦Summer Solstice occurs on June 21 or 22

Longest day of the year hours of sunlight begin to decrease

◦Winter Solstice occurs on December 21 or 22

Shortest day of the year hours of sunlight begin to increase

Southern Hemisphere◦Winter Solstice is in June◦Summer Solstice is in December

Occurs when the Sun is directly above the equator

Causes fall and spring#of daylight and night time hours are equal

Neither the Northern or Southern Hemisphere is tilted toward the Sun

Northern Hemisphere◦Spring Equinox-March 20 or 21◦Fall Equinox-September 22 or 23

Southern Hemisphere◦Spring Equinox-September◦Fall Equinox- March

Aim: How does the Moon move around the Earth?

Rotates on an axisRevolves around the EarthMoons rotation and revolution both take 27.3 days◦Because of this the same side of the moon always faces Earth

Moon’s surface reflects sunlight◦Half of the moon is lighted, while the other half is dark

The moon’s appearance changes as the Moon revolves around the Earth and you see different portions of its lighted side

Different forms that the moon takes in appearance from Earth

Phase depends on position of the moon, Earth and sun

New moon◦Occurs when the moon is between the

Earth and the sun◦Lighted half of the moon is facing the Sun

and dark side is facing the Earth◦can not be seen◦Rises and sets with the sun

Begins after a new moon Waxing-more of the illuminated half of the

moon can be seen each night Waxing crescent

◦ 24 hrs after a new moon you see a thin slice of the moon

First quarter phase◦ See ¼ of the moon’s surface

Waxing gibbous◦ More than ¼ of the moon is seen

Full moon◦ Occurs when all of the moon’s surface faces

Earth

Happens after a full moon You see less of the moon’s surface Waning gibbous

◦begins just after a full moon Third-quarter phase

◦See only half of the lighted side of the moon

Waning crescent◦Occurs just before a new moon

Takes about 29.5 days for the moon to complete its cycle of phases

Discrepancy between cycle of phases and the moons revolution is due to Earth’s revolution

Video

Caused by the revolution of the moon

Occur when the Earth or moon block out the sun

Can only occur when the sun, Earth and moon are lined up perfectly

Solar eclipse happens during a new moon

Lunar eclipse happens during a full moon

Occurs when the moon moves directly between the sun and the Earth

It casts a shadow over part of the Earth Umbra-darkest part of the Moon’s shadow

Experience a total solar eclipse-can only see a pearly white glow around the edge

Penumbra-lighter shadow that surrounds the umbra◦Experience a partial solar eclipse

Never look directly at the Sun, it can cause permanent eye damage

•Earth’s shadow falls on the Moon•Begins when the moon moves into the Earth’s penumbra•Curved shadow from Earth forms on the Moon•Total lunar eclipse-Moon completely in Earth’s umbra•Partial lunar eclipse-portion of the Moon moves into Earth’s umbra•Sunlight bent through Earth’s atmosphere-eclipse moon is red

craters-caused by meteorites, asteroids and comets

Dark, flat regions are called maria◦Formed from lava◦Igneous rock is 3-4 billion years old

Moon must have once been geologically active as Earth is today

Use seismograph to study moonquakes

Has helped them draw models of moons interior

Figure 11 Pg 671

Apollo mission supported a new theory about Moon:◦The Moon formed billions of years ago when Earth collided with a Mars-sized object

◦A ring of gas and debris formed around earth

◦Particles joined together to form the moon

Studying the moon has helped scientists draw conclusions about:◦Earth’s shape◦Movement of Earth and Moon around the Sun

◦Presence of surfaced features on bodies other than Earth