Lesson 2 Student Labs and Activities Page Launch Lab 25 Content Vocabulary 26 Lesson Outline 27 MiniLab 29 Content Practice A 30 Content Practice B 31 School to Home 32 Key Concept Builders 33 Enrichment 37 Challenge 38 Skill Practice 39. 24 The Solar System
Launch Lab LESSON 2: 20 minutes 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 Solar System 25
Content Vocabulary LESSON 2 Directions: 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. 26 The Solar System
Lesson Outline LESSON 2 A. Planets Made of Rock 1. The inner planets are those closest to the. They are also called the. 2. The inner planets are made of and metallic materials. 3. The outer layers of the inner planets are in the state. B. Mercury 1. is the planet closest to the Sun. 2. Mercury has no gases close to its surface, which means it has no. a. Because of its small mass, Mercury s is not strong enough to hold gases to its surface. b. Because Mercury has no wind to move energy from place to place, the temperatures on the side of Mercury facing the Sun are always extremely. 3. Mercury s surface is covered with impact, smooth plains, and high cliffs. 4. Mercury has a core made of and nickel. Its mantle C. Venus is made of oxygen and. 1. is the second planet from the Sun. a. Venus more slowly than it revolves, so a day on Venus is longer than a year on Earth. b. Unlike most other planets, Venus rotates from to. 2. Most of Venus s atmosphere is made up of. a. Venus is covered by a thick layer of. b. The clouds on Venus are made of. The Solar System 27
Lesson Outline continued 3. Venus is the planet in the solar system. a. The high temperatures on Venus are caused by the. b. The greenhouse effect increases surface temperature because the traps solar energy. 4. Most of the surface of Venus is covered by solidified. D. Earth 1. The third planet from the Sun is. 2. Earth s atmosphere is made up of and a mixture of gases. a. The atmosphere produces a(n) that increases Earth s average surface temperature. b. is supported on Earth because of its atmosphere, large bodies of liquid water, and moderate temperature range. 3. Earth has a solid inner core and a(n) outer core. The surrounds the outer core. a. Earth s crust is broken into large sliding. b. Earth s is made mostly of oxygen and silicon. E. Mars 1. Mars is the planet from the Sun. a. Mars has small moons. b. Many probes have examined the surface of Mars; most have looked for signs of. 2. Mars s atmosphere contains mostly. 3. Mars s surface appears to be red because its soil contains. a. Ice caps on Mars are made up of ice and frozen. b. Features on Mars s surface include craters, lava flows, canyons, and the largest known in the solar system. 28 The Solar System
MiniLab LESSON 2: 20 minutes How can you model the inner planets? In this lab, you will use modeling clay to make scale models of the inner planets. Planet Actual Diameter (km) Model Diameter (cm) Mercury 4,879 Venus 12,103 Earth 12,756 8.0 Mars 6,792 Procedure 1. Use the data above for Earth to calculate in the Data and Observations section below each model s diameter for the other three planets. 2. Use modeling clay to make a ball that represents the diameter of each planet. Check the diameter with a centimeter ruler. Data and Observations Analyze and Conclude 1. Explain how you converted actual diameters (km) to model diameters (cm). 2. Key Concept How do the inner planets compare? Which planets have approximately the same diameter? The Solar System 29
Content Practice A LESSON 2 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 M. has one moon N. hottest planet in the solar system O. southern hemisphere covered with craters P. closest to the Sun 30 The Solar System
Content Practice B LESSON 2 Directions: 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 gases near its surface, and a thin crust? The Solar System 31
School to Home LESSON 2 Directions: Use your textbook to complete the table. Some information has already been filled in. Planet Atmosphere Structure Surface Mercury 1. 2. 3. Venus 97 percent carbon dioxide; thick acid clouds 4. 5. Earth 6. 7. rocky crust of silicon and oxygen; crust broken into moving plates Mars 8. solid inner core; liquid outer core; mantle 9. 32 The Solar System
Key Concept Builder LESSON 2 Key Concept How are the inner planets similar? Directions: Complete the chart by answering each question in the space provided. Planet Atmosphere Structure Surface Moons Mercury 1. Why does Mercury not have an atmosphere? 2. Which two metals make up the core? 3. What covers the surface? 4. How many moons does Mercury have? Venus 5. What makes up the atmosphere? 6. What is different about this planet s rotation? 7. What covers 80 percent of the surface? 8. How many moons does Venus have? Earth 9. What does the atmosphere support? Mars 13. What makes up about 95 percent of the atmosphere? 10. What type of core does Earth have? 14. What covers the polar caps? 11. What makes up most of Earth s crust? 15. What causes the reddish color? 12. How many moons does Earth have? 16. How many moons does Mars have? The Solar System 33
Key Concept Builder LESSON 2 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. Characteristic Mercury Venus Earth Mars Has a solid outer layer Has an atmosphere Has wind Has a surface that shows erosion Has a solid inner core Has a liquid outer core Has impact craters Has at least one moon Has an iron and nickel inner core Has a crust Has a mantle Has a surface temperature greater than 200 C Has a surface temperature less than 150 C Has liquid water on its surface Has lava on its surface 34 The Solar System
Key Concept Builder LESSON 2 Key Concept Why is Venus hotter than Mercury? Directions: Explain each fact about the inner planets in the space provided. FACT Mercury has no wind. 1. FACT Venus is covered by a thick layer of clouds. 2. FACT The atmosphere of Venus is very dense with an atmospheric pressure that is 90 times greater than Earth s. 3. FACT Mercury experiences temperature extremes. 4. FACT Mercury does not experience a greenhouse effect. 5. FACT Venus is hotter than Mercury even though Mercury is closer to the Sun. 6. The Solar System 35
Key Concept Builder LESSON 2 Key Concept What kind of atmospheres do the inner planets have? Directions: Complete the table by listing three facts about the atmosphere or lack of atmosphere on each planet. Then answer each question. Planet Facts Question Mercury 1. Why doesn t Mercury have an atmosphere? 2. 3. Venus 1. Why is Venus the hottest planet in the solar system? 2. 3. Earth 1. 2. 3. Mars 1. 2. What factors enable life to exist on Earth? What causes great dust storms on Mars that last for months? 3. 36 The Solar System
Enrichment LESSON 2 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 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. Applying Critical-Thinking Skills Directions: 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? The Solar System 37
Challenge LESSON 2 Comparing the Inner Planets 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. Characteristics of Venus Both Characteristics of Earth 38 The Solar System
Skill Practice Graphing Data LESSON 2: 25 minutes 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 It Scientists 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. Planet Average Distance from the Sun (Au) Orbital Period (yr) Radius of Planet (km) Mercury 0.39 0.24 2440 Venus 0.72 0.62 6051 Earth 1.00 1.0 6378 Mars 1.52 1.9 3397 Jupiter 5.20 11.9 71,492 Saturn 9.58 29.4 60,268 Uranus 19.2 84.0 25,559 Neptune 30.1 164.0 24,764 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. The Solar System 39
Skill Practice continued 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. 40 The Solar System