The inner planets

1. The inner planets What do the inner planets have in common? what are their characteristics?

2. How do the inner and outer planets compare in size? The inner planets are all small compared to the outer planets. • What are two more shared characteristics of the inner planets? They are dense and rocky. • The inner planets are often called the terrestrial planets. Terra in Latin means earth.

3. The four inner planets are Mercury, Venus, Earth, Mars. • Which planet is largest? Earth • Which planet is smallest? Mercury. • Which planet has the most moons? Mars. • Which planet is most similar to Earth in size? Venus. • Students page 147 figure 1

4. Characteristics of the inner planets • Mercury is the smallest of the inner planets, and the planet closest to the sun. • It takes Mercury 88 days to orbit the sun, and it rotates on its axis 3 times for every two revolutions around the sun. • What features are similar on Mercury and Earth’s moon? Heavily cratered surfaces, little atmosphere, no liquid water, little erosion. • What differences do you see between the surface of Earth’s moon and the surface of Mercury? Mercury’s surface has no maria.

5. The temperature in Mercury can range from 430 Celsius to below 170 Celsius. • The interior of Mercury is probably made up off dense metal iron. • Students page 148 build inquiry, observe Mercury. Answer the question.

6. What are three very significant differences between Venus and Earth? • A) the pressure of Venus’s atmosphere is 90 times greater than the pressure of Earth’s atmosphere. • B)the news rotates from East to West and so slowly that its day is longer than its year. • C)Venus’s surface is much hotter than Earth’s. Hotter than any planet’s surface.

7. Earth rotates from West to East. • Venus rotates from East to West. • Venus and Earth are similar in size and mass. • Venus and Earth have different atmospheres and rotations. • Venus atmosphere is very thick and it’s always cloudy. The pressure of Venus atmosphere is 90 times greater than the pressure of Earth’s atmosphere. You couldn’t breathe on Venus because its atmosphere is mostly carbon dioxide.

8. the • Carbone dioxide in Venus’s atmosphere traps heat so well that Venus has the hottest surface of any planet. • Could astronauts land on Venus? probably not. The surface is so hot and the atmospheric pressure so great, that the first probe to land on Venus survived for only a few minutes. • carbon dioxide in Venus’s atmosphere acts like a garden greenhouse, trapping heat so well that Venu’s surface has an average temperature of 460 Celsius.

9. What characteristics does Earth have that enable living things to survive? Liquid water and the right temperature range and atmosphere. • How much liquid water does Earth has on its surface? about 70%. • How would conditions on earth be different if Earth were just a little farther from or closer to the sun? closer to the sun Earth would be so hot that liquid water would evaporate. Farther from the sun it will be colder so water would always be solid ice.

10. What enables Earth to hold onto a mix of gases that support life? Gravity area • Does oxygen make up most of Earth’s atmosphere? no, the atmosphere is mostly made up of nitrogen.

11. Mars is called the red planet. The color is due to the breakdown of iron rich rocks living a rusty dust behind. • What does Mars have in common with the other inner planets? Like Earth, Mars has seasons, volcanoes, polar caps, and water ice. Mars moons are covered with craters like Earth’s moon. The composition of Mars atmosphere is similar to Venus’s. • What distinguishes Mars from the other inner planets? unlike Earth and Venus, Mars has a very thin atmosphere. Mars has two moons.

12. Homework compare and contrast inner planets. Students use Venn diagrams to compare and contrast its inner planet with Earth. Name similarities between Venus and Earth, Mercury and Earth, Mars and Earth. Name differences between Mars and Earth, Venus and Earth, Mars and Earth.