Ch. 1- Lesson 1Earth’s Motion

Periods 1,3,5,7- Students should have these notes copied in notebooks with 3 questions on each page, and on 62,64, 66

Vocabulary and a bellringer on NB pg 61

Seasons descriptions on NB 63

Ch. 1 Outline on NB 65

Lesson 1-1• The nearest star to Earth is the Sun.

• The Sun is approximately 150 million km from Earth.

Earth and the Sun

Lesson 1-1Earth moves around the Sun in a nearly circular path.

Earth and the Sun (cont.)

Lesson 1-1• The path an object follows as it moves around

another object is an orbit.

• The motion of one object around another object is called revolution.

• Earth makes one complete revolution around the Sun every 365.24 days.

Earth and the Sun (cont.)

Lesson 1-1Earth orbits the Sun because the Sun’s gravity pulls on the Earth.

Earth and the Sun (cont.)

Lesson 1-1• A spinning motion is called rotation.

• The line on which an object rotates is the rotation axis.

• The tilt of Earth’s rotation axis is always in the same direction by the same amount.

• During half of Earth’s orbit, the north end of the rotation axis is toward the Sun and during the other half the north end of the rotation axis is away from the Sun.

Earth and the Sun (cont.)

Lesson 1-2Because Earth’s surface is curved, different parts of Earth’s surface receive different amounts of the Sun’s energy.

Temperature and Latitude

Lesson 1-2Relative to the direction of a beam of sunlight, Earth’s surface tends to become more tilted as you move away from the equator.

Temperature and Latitude (cont.)

Lesson 1-2The energy in a beam of sunlight tends to become more spread out the farther you travel from the equator (this picture is also on NB 61)

Temperature and Latitude (cont.)

Lesson 1-2Regions near the poles receive less energy than regions near the equator, which means Earth is colder at the poles and warmer at the equator.

Temperature and Latitude (cont.)

Lesson 1-3During one half of Earth’s orbit, the north end of the rotation axis is toward the Sun.

Seasons

Lesson 1-3• Due to Earth’s tilt, the northern hemisphere receives

more solar energy.

• Temperatures increase in the northern hemisphere and decrease in the southern hemisphere.

• This is when spring and summer happen in the northern hemisphere, and fall and winter happen in the southern hemisphere.

Seasons (cont.)

Lesson 1-3During the other half of Earth’s orbit, the north end of the rotation axis is away from the Sun.

Lesson 1-3• Due to Earth’s tilt, the southern hemisphere

receives more solar energy.

• Temperatures decrease in the northern hemisphere and increase in the southern hemisphere.

• This is when fall and winter happen in the northern hemisphere, and spring and summer happen in the southern hemisphere.

Seasons (cont.)

Lesson 1-3There are four days each year when the direction of Earth’s rotation axis is special relative to the Sun.

Seasons (cont.)

Lesson 1-3A solstice is a day when Earth’s rotation axis is the most toward or away from the Sun.

Seasons (cont.)

Lesson 1-3An equinox is a day when Earth’s rotation axis is leaning along Earth’s orbit, neither toward nor away from the Sun.

Seasons (cont.)

Lesson 1-3The Sun’s apparent path through the sky in the northern hemisphere is lowest on the December solstice and highest on the June solstice.

Seasons (cont.)