ch 20 sun-earth moon system

Question 1

Earth and the Sun

Answer 1

*Earth is always in motion, though it doesn’t seem that way when you look out the window.
*Day changes to night and back to day again
*The seasons change as the Earth travels around the Sun

Question 2

Sun

Answer 2

*Nearest star to Earth
*Sun’s diameter is 100 times greater than Earth

Question 3

Nuclear fusion

Answer 3

*nuclei of atoms combine releasing huge amounts of energy
*Small part of the sun’s energy reaches Earth as light and thermal energy.
*Is a giant ball of hot gasses that emits light and energy

Question 4

Earth’s orbit

Answer 4

*Nearly circular around the sun

Question 5

Orbit

Answer 5

*path an object follows as it moves around another object

Question 6

Revolution

Answer 6

*motion of one object around another object

Question 7

Law of Universal Gravitation

Answer 7

*the pull of gravity between two objects depends on the masses of the objects and the distance between them

Question 8

Rotation

Answer 8

*spinning motion

Question 9

Earth rotates

Answer 9

*on imaginary line through its center

Question 10

Rotation axis

Answer 10

the line on which an object rotates

Question 11

Earth rotates in what direction

Answer 11

*counterclockwise
*Takes about 24 hours
*Creates cycle of day and night
*Daytime for the side facing the sun
*Nighttime for facing away from the sun

Question 12

Earth’s rotation is always

Answer 12

*in the same direction by the same amount
*North end will be towards the sun for half of Earth’s orbit
*North end will be away from the sun for half of Earth’s orbit

Question 13

Tilt of Earth’s curved surface

Answer 13

*The Earth is not flat
*The Earth becomes more tilted as you move away from the equator
*Poles receive less energy than regions by the equator

Question 14

Seasons

Answer 14

*Caused by Earth’s motion around the sun along with the tilt of Earth’s rotation axis

Question 15

Spring and Summer in the Northern Hemisphere

Answer 15

*During one half of the rotation the northern half is closer to the sun.
*Receives more energy from the sun
*Temperatures increase
*Daylight hours are longer
*Fall and winter occur in the Southern hemisphere

Question 16

Fall and Winter in the Northern Hemisphere

Answer 16

*During one half of the rotation the northern half is away from the sun
*Receives less energy from the sun
*Temperatures decrease
*Daylight hours are less, nighttime is longer
*Spring and Summer occur in the Southern Hemisphere

Question 17

Solstice

Answer 17

*day when Earth’s rotation axis is the most toward or away from the sun

Question 18

Equinox

Answer 18

*day when Earth’s rotation axis is leaning along Earth’s orbit, neither toward nor away from the sun

Question 19

March equinox to June Solstice

Answer 19

*(Spring) - *north end of the rotation axis gradually points more toward the sun
*Northern hemisphere receives more solar energy

Question 20

June Solstice to September Equinox

Answer 20

(Summer)-north end of rotation axis points toward the sun but less and less
*Northern hemisphere receives less solar energy

Question 21

September Equinox to December Solstice

Answer 21

• (Fall)- north end of the rotation points more away from the sun
  *Northern hemisphere receives less solar energy

Question 22

December Solstice to March Equinox

Answer 22

*(Winter)- *north end of the rotation axis points away from the sun but less and less
*Northern hemisphere receives more solar energy

Question 23

Changes in the Sun’s apparent path across the sky

Answer 23

*The sun’s path across the sky is at its lowest during December Solstice
*The sun’s path across the sky is at its highest during June Solstice
*The sun’s path across the sky is about the same for March and September Equinox