Name______________________ Hr. _________ Date______________
Chapter 18.1 Notes Earth and Its Moon (Pgs. 424-429)
Revolving around Earth at a distance of 384,000 km is our only _____________.
on the moon thanks to _______________________________.
Humans have walked
I. Earth’s Shape and Orbit
A. Earth’s Shape
1. Earth’s shape is ________________________________.
2. The distance around Earth’s equator is 40, 076 km. This distance is called the ________________________.
3. The distance from one side to the other thorugh the center is called the _______________________.
4. The ____________________ of the Earth is the distance that is one half its diameter. Label the picture
below to illustrate the Earth’s dimensions; diameter, circumference and radius.
B. Earth’s orbit around the Sun
1.The shape Earth’s orbit and of the other planets are slightly__________________________.
2. The distance from Earth to the Sun varies as it revolves because the sun is not at the exact _______________
of Earth’s _____________.
3. According to figure 18.2 on page 424, in the northern hemisphere, Earth is closer to the sun at the beginning
of the ________________ season.
4. Remember, the distance that Earth is from the sun does not cause the seasons, the ___________ of Earth’s
____________ is what causes the Earth to have seasons due to the different amount of direct sunlight that each
hemisphere receives at different times of the year.
II. Comparing Earth and the Moon
A. How far away is the Moon?
1. Earth’s moon is ____________km away from the earth. However, the earth is ___________km away
from the sun.
2. So, this means the ______________is relatively very close to the earth when compared to
the distance the ___________ is away from the earth.
B. Diameter, Mass, Density
1. The moon’s diameter is about the length of the distance between ________________ and
_____________ in the USA.
2. The moon is about __________ the size of Earth.
3. Moon does not have an atmosphere because ______________________________________________ .
4. It would take about ___________moons to equal the mass of the Earth.
C. Gravitational force
1. The gravitational force of the moon is_______________________________________________ because
the moon’s ______________ is less than the earth’s.
2. A 2,500 pound car would weigh _____________ pounds on the moon.
3. Figure this out?? A student on earth weighs 100 pounds. How much would the same student weigh
on the moon? ________________
D. The Moon’s Rotation
1. The _____________ side of the moon always faces the __________.
2. The moon rotates much more slowly than the earth.
3. It takes the moon _____________ earth days to make one complete spin (rotation) on its axis
4. This is exactly the same time it takes the moon to make one ___________ around the Earth.
Use the space below to explain/illustrate the demonstration we did in class to show why and how we always see the
same side of the moon from earth.
III. How the Moon was formed
A. Where did the Moon come from? Different ideas1.
2.
3.
B. Analyzing lunar rocks
1. Lunar rocks composed of _______________________________________________ and this is much
like rocks found in Earth’s ____________________.
2. Earth’s core is composed of ____________________________________________
3. The density of the Moon’s rocks are like ________________________________________________.
C. The theory that is widely accepted today about the formation of the moon proposes that ________________
_________________________________________________________________________________________
_________________________________________________________________________________________.
IV. Surface Features of the Moon
A. Craters are ____________________________________ that are now believed to be caused by the
__________________________. For many years it was thought that the craters were caused by
____________________.
B. Highlands and Marias
1. Features on the moon appear as ___________ and ___________ areas.
2. The brighter areas are called ___________________ because they are ________________ in elevation.
3. ____________________are the darker areas which are actully low, dry areas that were once believed to
be ______________. We now believe these are low, dry areas that were covered with
______________________ when the moon formed. One of the largest marias is named
_________________________.
V. Tides—remember that all objects with mass exert a gravitational force on other objects with mass…..so….
A. Tides are caused by the moon’s gravity- (Read and review Figure 18.8 (p. 428))
1. A ___________________is a cycle of rising and falling of ocean levels.
2. In most places ocean levels ___________________________ twice each _____________as the Earth
rotates. We notice this change in ocean levels along the _________________________________ .
3. At _______ times during the day, the ocean(water line) comes up closer on
the beach than it does at other times during the day.
4. As Earth rotates beneath the moon, it feels a small tug of __________________ from the _________
on the side of the Earth closest to the moon. __________________ has less mass than rock, so the
water on earth “feels” the gravitational pull more than the rock surface does. In most places ocean
levels rise and fall ______________ each day as the moon revolves areound the Earth as the earth
rotates. The cycle of _________________and __________________of ocean levels is call
a________________________.
a. The _________________________is caused by the attraction of the Moon’s gravity pulling
on the side of on the earth that is facing the moon.
b. The cause of the ________________________ is caused by the ocean being _____________
outwards due to it’s own ____________ and the ________________ orbit around the earth.