Name______

Date______

Solar System Scale: Planetary Sizes

We have looked at how distances scale in our solar system. This activity will allow us to grasp the variation in the sizes of the planets within our system, as well as how a model would look were it to scale in both object size and distance.

Part 1:

Planet / Object representing planet / Diameter of object (cm)
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune

Table 1: Initial model

1. Copy Table 1 into your lab notebook.

2.Select one object from the bag to represent each of the eight planets.

3. Measure the diameter of each object (in cm).

4. Record the name of the object and the diameter in table 1.

5. Answer these reflection questions in your lab notebook:

A. What are the largest and the smallest planet in your system?

B. Do you observe any patterns in planet sizes? What are they?

C. Do you think your model is to scale in terms of planet size? Why or why not?

Part 2: When your entire group has finished the reflection questions for part one, have a teacher check them. Once your group has been checked off, you will receive a bag of objects. These objects are to scale in terms of diameter.

1. Copy table 2 into your lab notebook

2. Determine which object represents each planet

3. Measure the diameter of each object

4. Following the example in table 2, calculate the scale factor for this model.

Table 2: Calculating the Scale Factor

Planet / Actual Diameter (AD) (km) / Scaled Object / Scaled diameter (SD) (cm) / Scale Factor (sf) (km/cm)
sf=AD ÷ SD
Mercury / 4,878 / Small bead / 0.2 cm / Sf= 4874 km ÷ 0.2 cm = 24,390 km/cm
Venus / 12,102
Earth / 12,756
Mars / 6792
Jupiter / 142,980
Saturn / 120,536
Uranus / 51,118
Neptune / 49,528
Average Scale Factor (km/cm)

Part 3: Using the average scale factor from part 2 and the information in table three, calculate the distances from the sun for the planets in your model. Copy and fill in table 3.

Table 3: Calculating scaled distance

Scale factor (sf): 1 cm= ______km
Planet / Actual Distance from sun (km) ADs / Scaled Distance (SDs) (cm)
SDs= ADs ÷ sf / Scaled distance converted (m)
Mercury / 57,900,000
Venus / 108,200,000
Earth / 149,600,000
Mars / 228,000,000
Jupiter / 778,400,000
Saturn / 1,426,700,000
Uranus / 2,866,900,000
Neptune / 4,486,100,000

Reflection Questions:

A. How is your second model similar and different from your first model?

B. How is your model similar and different than the actual solar system?

C. What is the relationship between the sizes of the planets and their distances from the sun? What reason do you have for this answer?

D. How do the distances between the first four planets compare with the distances between the other planets?