Download PATTERNS OF MASS AND DENSITY IN THE SOLAR SYSTEM

PATTERNS OF MASS AND DENSITY IN THE SOLAR SYSTEM
Name: ____________________________________
Date: ______________
Purpose: To investigate the patterns of mass, density, and size of planets in the solar system and
compare the terrestrial and giant planets.
Background: Mass is a measure of the amount of matter an object contains. The masses of the
planets on the Planet Data Table are given in relation to Earth’s mass. For example, mercury’s mass
is given as 0.056, which means that it contains only a small fraction of the matter that Earth contains.
On the other hand, the giant planets contain several times more matter than Earth. Density is the
amount of matter in a given amount of space, or the mass per unit volume of a substance. The
average densities on the Planet Data Table are expressed in grams per cubic centimeter (g/cm3). For
density, the density of pure water is approximately 1 g/cm3.
Hypothesis: What relationship do you think you will observe between the mass, density, and size of
planets.
Procedure: Refer to the Planet Data Table handout to find the information needed to answer the
following questions. Answer in complete sentences unless answer is a fill-in.
1.
2.
The planet ____________________ is the most massive planet in the solar system. It is
_______________ times more massive than Earth.
The least massive planet (excluding Pluto) is _________________________, which contains
only _______________ as much mass as Earth.
The gravitational attraction of a planet is directly related to its mass. In other words, as a planet’s
mass increases, its gravitational attraction increases.
3.
Which planet exerts the greatest pull of gravity? Explain your answer.
Your weight is a function of the gravitational attraction of an object acting on your mass.
4.
On which planet (excluding Pluto) would you weigh the least? Explain your answer.
5.
Which of the two groups of planets, terrestrial or giant, would have the greatest ability to hold
large quantities of gas as part of their composition? Explain your answer.
6.
Write a general statement comparing the masses of the terrestrial planets to the masses of the
giant planets.
7.
Plot a point on the graph below for each planet (excluding Pluto). The point should be plotted
where the planet’s diameter intersects its density. Use the diameter measurements in kilometers
from the Planet Data Table. Label each point with the planet’s name. Use a different color for
the terrestrial planets and the giant planets. Give the graph a title and include a key.
DIAMETER (km X 1000)
150
100
50
0
0
1.0
2.0
3.0
4.0
5.0
6.0
DENSITY (g/cm3)
8.
What general relationship exists between a planet’s diameter and its density?
Circle your answers for the next two questions.
9. The densities of the two rock types that form the majority of Earth’s surface, the igneous rocks
granite and basalt, are each about 3.0 g/cm3. The average densities of the terrestrial planets are
(greater than, less than) the density of Earth’s surface rocks. The average densities of the giant
planets are (greater than, less than) the density of Earth’s surface rocks.
10. The term (rocky/gaseous) best describes the terrestrial planets.
11. The average density of Earth is about 5.5 g/cm3. Considering that the densities of Earth’s
surface rocks are much less than Earth’s average density, you could infer that the center of the
Earth is made of _____(rock/gas) that is (more than /less than) 5.5g/cm3________.
12. Which of the planets has a density less than water and could therefore “float” (if you could find
a large enough container!)? ______________________________
13. Circle your answer. The giant planets can best be described as (rocky, ice and gas) worlds.
14. Write a general statement comparing the densities of the terrestrial planets to the densities of the
giant planets.
15.
Why are the inner and outer planets densities so different? Consider both what you found out on
your graph and also what you know about composition to support your statements
16.
Examine the estimated mass, diameter and density of Pluto. Complete the following statements
by circling the correct response.
The mass of Pluto is most like the masses of the (terrestrial, giant) planets, while the density is
similar to that of the (terrestrial, giant) planets. This suggests that Pluto is a (small, large) body
made of (rock, ice and frozen gas).
17. Pluto makes up the Kuiper belt. What do you think the other objects in the Kuiper belt would be
like in terms of density and composition (use the data in the chart and the patterns seen to support
your statement)?
18. If the material in the asteroid belt (2.8AU) had coalesced to form a planet, what do you think it
would have been like? Would it likely have been a terrestrial planet or a Jovian planet? Explain your
reasoning
19. Make a T chart of the terrestrial vs. the Jovian planets. List as many properties as possible based
on this lab and also based on info. in the planetary data table
22. Why do the inner and outer planets differ? (Hint: think about the Nebular Hypothesis)
PART 2 Density of Moons
We know that rocks have an average density of 3.5g/cm3 and ice has a density of 0.9 g/cm3. We can
calculate the density of a moon by using the following formula:
(3.5 x percentage of rock) + (0.9 x percentage of ice) = density
100
DENSITY OF MOON
Use the formula above to find the densities to complete the chart:
Percent rock
Percent Ice
Density of
moon g/cm3
100
0
3.5
80
20
60
40
40
60
20
80
0
100
Make a line graph below of the density of moon vs. the percent Rock. Give it a title.
3.0
2.0
1.0
% ROCK
1. Jupiter’s moon Ganymede has a density of 1.9 g/cm3. Based on your graph what percentage of it
is rock?
2. Neptune’s moon Triton has a density of 2.1 g/cm3 and would therefore be ____% rock.
3. Jupiter’s moon Europa has a density of 3.0g/cm3. What is its % of rock?