Regents Earth Science Date Started ______

Time ________ Name ___________________________

Regents Earth Science Date started _________________

Astronomy Due date __________ Period ___

Lab: Scale Model of the Solar System

Introduction: Actual distances of planets are difficult to visualize. The actual size of stars, like our Sun, is difficult to understand. Astronomers often use scale models or proportions to help make large distances meaningful. Engineers use scale models of airplanes, cars and boats, to give meaning and understanding.

The solar system’s radius is approximately 4.5 billion kilometers. The Sun is over 100 times the size of the Earth. During this lab, you will be calculating scale proportions, in order to give meaning, to large distances and sizes. Perhaps at the conclusion of the lab, we can make scale models of the Sun and planets, and then place them in the hall. Let’s see how many planets we can “fit” in the hall, to scale.

Preparation: Before you start calculating scale proportions, let’s review the term scale by reviewing an old topic, topographic map scales (text book p.46-47). Find a text and look over those pages. Recall that on a map scale of “1 inch to 50 statute miles”…1 inch on the map is equal to 50 miles in the surface of the Earth, or “1 inch : 50 statute miles”. Remember that the first number means on the model, the second number means on the actual object. Example, many model airplanes are 1/48 scale, which is equal to 1:48. That ratio means that 1cm on the model is equal to 48cm on the actual airplane. The scale that you will be using during this lab is “1 meter is equal to 1 solar diameter”, in other words “1 meter on the model is equal to 1,392,000 kilometers on the actual”.

How are your skills at scientific notation? Review text p.730-731 if you need help. One solar diameter is 1,392,000 kilometers or 1.392 x 106 km.

You will need one last reference source, you ESRT p.15 Solar System Data. This data table will be your source of Mean distance from the Sun (millions of km) and planetary Equatorial diameter (km). During this lab you will be calculating scale distances from the Sun, as well as scale equatorial diameters of the planets, using the same scale of “1m : 1,392,000km”.

Procedure:

1. Make a hypothesis: How large and how far away, would a scale model of the Earth be from the Sun, using the scale: 1 meter = Sun’s diameter? Take your best guess.

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2. Here is an example of how to find the scale distance from the Sun to Mercury. We will use the scale ratio of “1m: 1,392,000 km”. This is an example of “showing your math”. You will need to “show your math” for step three and further questions. Mercury scale distance:

Here is an example of “showing the math” using Microsoft Word:

5.79 x 107 km x (1m / 1.392 x 106 km ) = 41.595m

Here is an example of “showing the math” using Equation Editor (a little complicated): Mercury scale distance:

Mean distance from the Sun for Mercury Our scale ratio of “1m : 1,392,000 km”

Also notice, in the above example, that we have “km” in the numerator…and “km” in the denominator so the “km” cancel out, leaving units of “m”.

3. You may want to word process or find some blank paper or lined paper and “show the math,” for the selected planet distances from the Sun: Venus, Earth, Jupiter and Neptune. Use your ESRT p.15 for your Mean Distances from the Sun values . Please label each “show the math”…example: Mercury scale distance. Staple this sheet to the back of your lab, when you have completed the calculations.

4. In step 2, you have examples of finding the scale distance. Now, here are examples of finding the scale diameter of selected planets.

We will use the same scale ratio of “1m : 1,392,000 km”. This is an example of “showing your math”. You will need to “show your math” for step four and further questions. Mercury scale diameter:

Here is an example of “showing the math” using Microsoft Word:

4880 km x (1m / 1.392 x 106 km) = 0.0035m = 3.5mm

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Here is an example of “showing the math” using Equation Editor: Mercury scale diameter:

Diameter of Mercury Our scale ratio of “1m : 1,392,000 km”

Also notice, in the above example, that we have “km” in the numerator…and “km” in the denominator so the “km” cancels out, leaving units of “m”. Since 0.0035m is a difficult measurement, change meters to millimeters for the selected planet diameters.

5. “Show the math,” for the selected planet diameters: Venus, Earth, Jupiter and Neptune. Use your ESRT p.15 for your Equatorial diameter values. Please label each “show the math”…example: Mercury scale diameter. Staple this sheet to the back of your lab, when you have completed the calculations.

6. Go to the following web site: http://www.exploratorium.edu/ronh/solar_system/index.html

Read the introduction. Go to page 2 and place the number “1000” in the space below “Body Diameter (mm), then click on the calculate button. You will then confirm you calculations for your scale distances and diameters. Correct any errors in your calculated scale answers…how cool!

7. Construct a data table of your scale distances and diameters of the selected planets. Include this title: Scale distances and diameters of selected planets. You may draw or use a word processor. Staple this data table to the back of the lab.

Conclusion questions:

1. a) Calculate the scale distance Mars would be from the Sun using the scale: “1m : 1,392,000 km”. Show the math on the space below.

b) Calculate the scale diameter of Mars using the scale: “1m : 1,392,000 km”. Show the math on the space below.

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2. Answer the following questions: Research on-line about the following topic questions. Explain fully.

a) What is the definition of “planet”. __________________________________

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b) Why is Pluto, no longer, classified as a planet? ____________________________

c) What are the components of the Kuiper Belt? _______________________________

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