Student Exploration : Solar System Explorer
Vocabulary: astronomical unit, dwarf planet, eccentricity, ellipse, gas giant, Kepler’s laws, orbit, orbital radius,
period, planet, solar system, terrestrial planet
Gizmo Warm-up
The Solar System Explorer Gizmo shows a model of the solar system. All
of the distances, but not the sizes of the planets, are shown to scale. To
begin, turn on Show orbital paths and click Play ( ). You are looking at
the four inner planets.
1. In which direction do planets go around the Sun, clockwise or
counterclockwise?
counterclockwise
2. An orbit is the path of a body around another body.
What is the shape of the planetary orbits around the Sun? about orbital
3. Click Pause ( ). You can see the name of each planet by holding your cursor over the planet. What is
the order of the eight planets, starting from the Sun? Click the “zoom out” button ( ) to see the outer
planets and Pluto, which is classified as a dwarf planet.
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune
Activity A:
Get the Gizmo ready:
Classifying ● Click Reset ( ).
planets
Planets Classification
4. Gather data: Select Mercury from the Solar system menu at left. Turn on Additional data. In the table
below, record Mercury’s Mass, Mean radius, and Density. Then repeat for each of the other planets as well
as the dwarf planet Pluto. Include units.
Planet Mass (×1023 kg) Mean radius (km) Density (g/cm3)
Mercury 3.3×1023 kg 2440 km 5.427 g/cm3
Venus 48.7×1023 kg 6052 km 5.243 g/cm3
Earth 59.7×1023 kg 6378 km 5.515 g/cm3
Mars 6.4×1023 kg 3397 km 3.933 g/cm3
, Jupiter 18,990×1023 kg 71490 km 1.326 g/cm3
Saturn 5680×1023 kg 60270 km 0.687 g/cm3
Uranus 869×1023 kg 25560 km 1.270 g/cm3
Neptune 1020×1023 kg 24760 km 1.638 g/cm3
Pluto (dwarf planet) .1×1023 kg 1195 km 1.750 g/cm3
5. Analyze: What patterns do you notice in your data table?
inner planets have lower masses but higher densities while outer planets have higher masses
but lower densities
6. Summarize: Compare the masses, radii, and densities of the terrestrial planets and the gas giants.
A. What do the terrestrial planets have in they are all low in mass but high in
common? density
B. the gas giants have in common? they are all high in mass but low in
density
7. Extend your thinking:
Why doesn’t Pluto fit into either the terrestrial planet Pluto has too small of a mass to be a
group or the gas giant group? gas giant and too small a density to be
a terrestrial planet
8. Think and discuss: Why do you think the inner planets are small and dense, while the outer planets are gas
giants?
I think the inner planets are dense and small because since they’re closer to the sun, they are
more affected by gravity which makes them compact as much as possible, while the outer
planets are still held together by gravity but not as much since they’re so far away.
Get the Gizmo ready:
Activity B:
● Click Reset.
Planetary orbits ● Click the “zoom in” button ( ) several times to
zoom in as far as possible.
Introduction: Johannes Kepler (1571–1630) was a German astronomer who spent years poring over a vast
store of planetary data compiled by his predecessor, Tycho Brahe. After many incorrect theories and other
setbacks, Kepler at last determined the beautifully simple physical laws that govern orbiting bodies. These
rules are now known as Kepler’s laws.
Kepler’s laws: Rules to describe the size and shape of planetary orbits?
9. Observe: Select Mercury from the Solar system menu. Look at Mercury’s orbit.
Vocabulary: astronomical unit, dwarf planet, eccentricity, ellipse, gas giant, Kepler’s laws, orbit, orbital radius,
period, planet, solar system, terrestrial planet
Gizmo Warm-up
The Solar System Explorer Gizmo shows a model of the solar system. All
of the distances, but not the sizes of the planets, are shown to scale. To
begin, turn on Show orbital paths and click Play ( ). You are looking at
the four inner planets.
1. In which direction do planets go around the Sun, clockwise or
counterclockwise?
counterclockwise
2. An orbit is the path of a body around another body.
What is the shape of the planetary orbits around the Sun? about orbital
3. Click Pause ( ). You can see the name of each planet by holding your cursor over the planet. What is
the order of the eight planets, starting from the Sun? Click the “zoom out” button ( ) to see the outer
planets and Pluto, which is classified as a dwarf planet.
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune
Activity A:
Get the Gizmo ready:
Classifying ● Click Reset ( ).
planets
Planets Classification
4. Gather data: Select Mercury from the Solar system menu at left. Turn on Additional data. In the table
below, record Mercury’s Mass, Mean radius, and Density. Then repeat for each of the other planets as well
as the dwarf planet Pluto. Include units.
Planet Mass (×1023 kg) Mean radius (km) Density (g/cm3)
Mercury 3.3×1023 kg 2440 km 5.427 g/cm3
Venus 48.7×1023 kg 6052 km 5.243 g/cm3
Earth 59.7×1023 kg 6378 km 5.515 g/cm3
Mars 6.4×1023 kg 3397 km 3.933 g/cm3
, Jupiter 18,990×1023 kg 71490 km 1.326 g/cm3
Saturn 5680×1023 kg 60270 km 0.687 g/cm3
Uranus 869×1023 kg 25560 km 1.270 g/cm3
Neptune 1020×1023 kg 24760 km 1.638 g/cm3
Pluto (dwarf planet) .1×1023 kg 1195 km 1.750 g/cm3
5. Analyze: What patterns do you notice in your data table?
inner planets have lower masses but higher densities while outer planets have higher masses
but lower densities
6. Summarize: Compare the masses, radii, and densities of the terrestrial planets and the gas giants.
A. What do the terrestrial planets have in they are all low in mass but high in
common? density
B. the gas giants have in common? they are all high in mass but low in
density
7. Extend your thinking:
Why doesn’t Pluto fit into either the terrestrial planet Pluto has too small of a mass to be a
group or the gas giant group? gas giant and too small a density to be
a terrestrial planet
8. Think and discuss: Why do you think the inner planets are small and dense, while the outer planets are gas
giants?
I think the inner planets are dense and small because since they’re closer to the sun, they are
more affected by gravity which makes them compact as much as possible, while the outer
planets are still held together by gravity but not as much since they’re so far away.
Get the Gizmo ready:
Activity B:
● Click Reset.
Planetary orbits ● Click the “zoom in” button ( ) several times to
zoom in as far as possible.
Introduction: Johannes Kepler (1571–1630) was a German astronomer who spent years poring over a vast
store of planetary data compiled by his predecessor, Tycho Brahe. After many incorrect theories and other
setbacks, Kepler at last determined the beautifully simple physical laws that govern orbiting bodies. These
rules are now known as Kepler’s laws.
Kepler’s laws: Rules to describe the size and shape of planetary orbits?
9. Observe: Select Mercury from the Solar system menu. Look at Mercury’s orbit.
