Lesson 2 | The Inner Planetsimages.pcmac.org/SiSFiles/Schools/AL/MobileCounty/... · Name Date Class Content Practice B LESSON 2 The Inner Planets Directions: Answer each riddle by
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What affects the temperature on the inner planets?Mercury and Venus are closer to the Sun than Earth. What determines the temperature on these planets? Let’s find out.
Procedure 1. Read and complete a lab safety form.
2. Insert a thermometer into a clear 2-L plastic bottle. Wrap modeling clay around the lid to hold the thermometer in the center of the bottle. Form an airtight seal with the clay.
3. Rest the bottle against the side of a shoe box in direct sunlight. Lay a second thermometer on top of the box next
to the bottle so that the bulbs are at about the same height. The thermometer bulb should not touch the box. Secure the thermometer in place using tape.
4. Read the thermometers and record the temperatures below.
5. Wait 15 minutes and then read and record the temperature on each thermometer.
Data and Observations
Think About This 1. How did the temperature of the two thermometers compare?
2. Key Concept What do you think caused the difference in temperature?
The Inner PlanetsDirections: On each line, write the term from the word bank that correctly completes each sentence. NOTE: You may need to change a term to its plural form.
Earth greenhouse effect Mars
Mercury terrestrial planet Venus
1. Earth, Mars, Mercury, and Venus are .
2. is the closest planet to the Sun and has no atmosphere.
3. has an atmosphere made of water vapor and gases.
4. The occurs when a planet’s atmosphere traps solar energy and causes the surface temperature to increase.
5. is about the same size as Earth.
6. has soil that contains iron oxide, which makes its surface appear reddish in color.
The Inner Planets Directions: Match each fact with the correct planet by writing the letter of each fact in the correct box. Each fact is used only once.
Mercury
Venus
Earth
Mars
A. period of rotation = 24 hours
B. polar ice caps made of frozen carbon dioxide
C. surface features last for billions of years because of little erosion
D. surface always covered by thick clouds
E. period of rotation = 244 days
F. period of revolution = 1.88 years
G. has soil rich in iron oxide
H. has no atmosphere or winds
I. third planet from the Sun
J. atmosphere made up of 95 percent carbon dioxide
K. period of rotation = 59 days
L. 80 percent of surface is covered by solidified lava
The Inner PlanetsDirections: Answer each riddle by writing the name of the correct inner planet on the line provided.
1. Which planet is 5.5 percent of Earth’s mass and has no moon?
2. Which planet has an average distance from the Sun of 1.52 AU, the compound iron
oxide present in its surface, and carbon dioxide ice caps?
3. Which planet is hotter than Mercury, has a longer period of rotation than revolution,
and has an atmosphere of about 97 percent carbon dioxide?
4. Which planet has the largest known mountain in the solar system, two moons, and
a period of rotation equal to 24.6 hours?
5. Which planet has the presence of liquid water, a period of rotation equal to 24 hours,
and a solid inner core?
6. Which planet is the only planet with liquid water on its surface, a liquid outer core,
and a crust broken into large plates?
7. Which planet shows no evidence of life, experiences great dust storms, and has
a volcano on it as wide as Arizona?
8. Which planet has clouds of acid and an atmospheric pressure that is 90 times greater than Earth’s but an internal structure that is similar to Earth’s?
9. Which planet has a liquid outer core, a mantle, and an atmosphere that protects life
from the Sun’s radiation?
10. Which planet has the greatest extremes of temperature depending on which side faces
the Sun, a thin crust, and a core made of iron and nickel?
11. Which planet has an average temperature of 460°C, has no water in its atmosphere,
and rotates from east to west?
12. Which planet has a cracked and wrinkled surface, gravity so small that it cannot hold
The Inner Planets Key Concept How are the inner planets similar?
Directions: Complete this table by putting a check mark under each planet that the characteristic applies to. The first two lines have been completed for you.
Applying Critical-Thinking SkillsDirections: Answer each question or respond to each statement.
1. Predict what would happen to Earth’s Moon if the force of gravity stopped.
2. Hypothesize what would happen to the Moon if its forward motion stopped.
3. Infer If you have ever gazed at the Milky Way on a clear night, you know that our galaxy is composed of countless objects: suns, planets, asteroids, comets, gas, and dust. These objects orbit around the center of the Milky Way. What can you infer is at the center of the Milky Way?
An object at rest will tend to stay at rest. An object in motion will tend to stay moving in a straight line, unless acted upon by an external, unbalanced force. This is Newton’s first law of motion. If you roll a ball on a level surface, it will roll in a straight line until the force of friction (an external, unbalanced force) stops it. In space, there is very little friction to slow the planets, but they don’t travel in a straight line. The external, unbalanced force that keeps the planets in curved orbits is gravity.
Gravitational Force We usually go about our lives without
giving much thought to gravity. We can’t notice the pull of gravity we have on Earth, but we surely notice the pull of gravity Earth has on us, especially when we fall
LESSON 2
down. But the pull of gravity exists between every pair of objects that have mass. The more massive an object is, the more gravity it has.
Staying in Orbit Gravity keeps the planets in orbit
around the Sun, the moons around the planets, and the Sun around the center of the Milky Way. Mass and distance determine which object orbits another object. Small satellites such as the Moon are attracted to the nearest larger object with mass, as Earth attracts the Moon. Mars doesn’t orbit Jupiter because the Sun is far more massive than Jupiter and Jupiter is far away from Mars. Mars is about 228,000,000 km from the Sun and about 551,000,000 km from Jupiter.
Use the Venn diagram below to compare the characteristics of Venus and Earth. Describe the features they share in the center area of the diagram. Differentiate between the greenhouse effect on Venus and the greenhouse effect on Earth in a brief essay.
What can we learn about planets by graphing their characteristics?Scientists collect and analyze data, and draw conclusions based on data. They are particularly interested in finding trends and relationships in data. One commonly used method of finding relationships is by graphing data. Graphing allows different types of data be to seen in relation to one another.
Learn ItScientists know that some properties of the planets are related. Graphing data makes the relationships easy to identify. The graphs can show mathematical relationships such as direct and inverse relationships. Often, however, the graphs show that there is no relationship in the data.
Try It 1. You will plot two graphs that explore the relationships in data. The first graph
compares a planet’s distance from the Sun and its orbital period. The second graph compares a planet’s distance from the Sun and its radius. Make a prediction about how these two sets of data are related, if at all. The data are shown in the table.
2. Use the data in the table to plot a line graph below showing orbital period versus average distance from the Sun. On the x-axis, plot the planet’s distance from the Sun. On the y-axis, plot the planet’s orbital period. Make sure the range of each axis is suitable for the data to be plotted and clearly label each planet’s data point.
3. Use the data in the table to plot a line graph showing planet radius versus average distance from the Sun. On the y-axis, plot the planet’s radius. Make sure the range of each axis is suitable for the data to be plotted and clearly label each planet’s data point.
Apply It 4. Examine the Orbital Period v. Distance from the Sun graph. Does the graph show a
relationship? If so, describe the relationship between a planet’s distance from the Sun and its orbital period.
5. Examine the Planet Radius v. Distance from the Sun graph. Does the graph show a relationship? If so, describe the relationship between a planet’s distance from the Sun and its radius.
6. Key Concept Identify one or two characteristics the inner planets share that you learned from your graphs.