SCIENCE EXPERIMENTS ON FILE™ Revised Edition

3.10-1

Scale Model of Our Solar System Sue Anne Nothstine

Topic Solar system/measurements to scale

Time 2 hours

!

Safety Please click on the safety icon to view safety precautions.

Materials handful of clay metric ruler basketball 13-m adding machine tape

football field or public park pencil metric tape measure

Procedure PART A

1. Make two copies of the data table. Label them A and B. 2. Fill in data table A by making the following calculations: a. The scale for this model of the solar system is 1 cm = 50,000 km. To find the scale diameter of each planet, divide the mean diameters in column 2 of the data table by 50,000. Enter your results in column 3. b. To find the scale distance of each planet from the sun, take the actual distances listed in column 4 and divide them by 50,000. Enter your results in column 5. (Note that the figures in column 4 refer to millions of kilometers, so that the number 58 stands for 58,000,000. ) c. To figure out the travel time of light between planets, take the actual distance listed in column 4. Divide this number by 300,000 km/sec, the speed of light. Record the result in column 6. 3. To make your model of the solar system, first form the planets from clay by using the scale diameters in column 3. Use a basketball for the sun. 4. Now take your model planets to a football field or public park. Measure off the scale distances in column 5 to position each planet. 5. If you encounter any problems in completing your scale model, return home and try Part B.

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3.10-2

SCIENCE EXPERIMENTS ON FILE™ Revised Edition

PART B

1. Look at data table A again, and fill in data table B. Divide each figure in column 3 and column 5 by 100. This will give you a new scale of 1 cm = 5,000,000 km. 2. Using your new scale, mark the position of the planets and sun, and place them on the adding machine tape. 3. How successful was your attempt to make a scale model in Part A? Describe any problems you encountered and explain their cause. 4. How successful was your attempt to make a scale model in Part B? Describe any problems you encountered and explain their cause. 5. What was the most surprising thing about this experiment? 6. Compare the relative sizes of planets close to the sun with the sizes of those farther from the sun. How do you explain the difference? 7. Which planet doesn’t fit the pattern you found in step 4? Explain your answer.

D ATA T A B L E A Scale: 1 cm = 50,000 km 1

2

3

4

5

6

Object

Mean diameter (km)

Scale diameter (cm)

Mean distance from sun (million km)

Scale distance from sun (cm)

Travel time (sec)

Sun

1,392,000

27.840

Mercury

4,900

58

Venus

12,100

108

Earth

12,800

150

Mars

6,800

228

Jupiter

142,800

778

Saturn

120,000

1,427

Uranus

51,000

2,870

Neptune

48,600

4,500

3,000

5,900

Pluto

What’s Going On Using the scale 1 cm 4 50,000 km, the solar system will not fit in an area the size of a football field. Approximately three-quarters of a mile is needed. Although it is possible to see the relative distances between the planets using a scale of 1 cm = 5,000,000 km, the planets themselves would be too small to be seen

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SCIENCE EXPERIMENTS ON FILE™ Revised Edition

3.10-3

by the naked eye, and only their relative position may be marked. This further illustrates the enormous size of the solar system and how small the planets are in relation to these distances. The planets close to the sun are smaller than those farther away because the inner planets are terrestrial in nature, while the outer planets are thought to be composed largely of gases. Pluto, which is small, does not fit the pattern. It is composed of ices rather than gases. The distances between planets and the distances of planets from the sun are hard to imagine. This demonstration helped you understand these relationships. D ATA T A B L E B Scale: 1 cm = 5,000,000 km

Object

Mean diameter (km)

Scale diameter (cm)

Sun

1,392,000

27.840

4,900

.098

58

1,160

193

Venus

12,100

.242

108

2,260

360

Earth

12,800

.256

150

3,000

500

Mars

6,800

.136

228

4,560

760

Jupiter

142,800

2.856

778

15,560

2,593

Saturn

120,000

2.400

1,427

28,540

4,757

Uranus

51,000

1.020

2,870

57,400

9,567

Neptune

48,600

.972

4,500

90,000

15,000

3,000

.060

5,900

118,000

19,667

Mercury

Pluto

Mean distance from sun (million km)

Scale distance from sun (cm)

Travel time (sec)

Connections Our solar system is vast. When you look up at the night sky, you see a mixture of stars and planets. How can you be sure that it is a planet? You can identify the planets in the night sky by (a) looking for a steady shine, not the blinking light that is exhibited by stars, (b) by observing the movement of the planets over time (stars do not move), (c) by observing that the planets appear larger and disklike through a telescope and stars appear pointlike, and (d) planets appear to remain in a path that the sun follows, but stars are distributed throughout the sky.

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Safety Precautions READ AND COPY BEFORE STARTING ANY EXPERIMENT

Experimental science can be dangerous. Events can happen very quickly while you are performing an experiment. Things can spill, break, even catch fire. Basic safety procedures help prevent serious accidents. Be sure to follow additional safety precautions and adult supervision requirements for each experiment. If you are working in a lab or in the field, do not work alone. This book assumes that you will read the safety precautions that follow, as well as those at the start of each experiment you perform, and that you will remember them. These precautions will not always be repeated in the instructions for the procedures. It is up to you to use good judgment and pay attention when performing potentially dangerous procedures. Just because the book does not always say “be careful with hot liquids” or “don’t cut yourself with the knife” does not mean that you should be careless when simmering water or stripping an electrical wire. It does mean that when you see a special note to be careful, it is extremely important that you pay attention to it. If you ever have a question about whether a procedure or material is dangerous, stop to find out for sure that it is safe before continuing the experiment. To avoid accidents, always pay close attention to your work, take your time, and practice the general safety procedures listed below. PREPARE

• Clear all surfaces before beginning work. • Read through the whole experiment before you start. • Identify hazardous procedures and anticipate dangers. PROTECT YOURSELF

• Follow all directions step by step; do only one procedure at a time. • Locate exits, fire blanket and extinguisher, master gas and electricity shut-offs, eyewash, and first-aid kit. • Make sure that there is adequate ventilation. • Do not horseplay. • Wear an apron and goggles. • Do not wear contact lenses, open shoes, and loose clothing; do not wear your hair loose. • Keep floor and work space neat, clean, and dry. • Clean up spills immediately. • Never eat, drink, or smoke in the laboratory or near the work space. • Do not taste any substances tested unless expressly permitted to do so by a science teacher in charge. USE EQUIPMENT WITH CARE

• Set up apparatus far from the edge of the desk. • Use knives and other sharp or pointed instruments with caution; always cut away from yourself and others. • Pull plugs, not cords, when inserting and removing electrical plugs. • Don’t use your mouth to pipette; use a suction bulb. • Clean glassware before and after use. • Check glassware for scratches, cracks, and sharp edges. • Clean up broken glassware immediately. v © Facts On File, Inc.

vi

Safety

SCIENCE EXPERIMENTS ON FILE™ REVISED EDITION

• Do not use reflected sunlight to illuminate your microscope. • Do not touch metal conductors. • Use only low-voltage and low-current materials. • Be careful when using stepstools, chairs, and ladders. USING CHEMICALS

• Never taste or inhale chemicals. • Label all bottles and apparatus containing chemicals. • Read all labels carefully. • Avoid chemical contact with skin and eyes (wear goggles, apron, and gloves). • Do not touch chemical solutions. • Wash hands before and after using solutions. • Wipe up spills thoroughly. HEATING INSTRUCTIONS

• Use goggles, apron, and gloves when boiling liquids. • Keep your face away from test tubes and beakers. • Never leave heating apparatus unattended. • Use safety tongs and heat-resistant mittens. • Turn off hot plates, bunsen burners, and gas when you are done. • Keep flammable substances away from heat. • Have a fire extinguisher on hand. WORKING WITH MICROORGANISMS

• Assume that all microorganisms are infectious; handle them with care. • Sterilize all equipment being used to handle microorganisms. GOING ON FIELD TRIPS

• Do not go on a field trip by yourself. • Tell a responsible adult where you are going, and maintain that route. • Know the area and its potential hazards, such as poisonous plants, deep water, and rapids. • Dress for terrain and weather conditions (prepare for exposure to sun as well as to cold). • Bring along a first-aid kit. • Do not drink water or eat plants found in the wild. • Use the buddy system; do not experiment outdoors alone. FINISHING UP

• Thoroughly clean your work area and glassware. • Be careful not to return chemicals or contaminated reagents to the wrong containers. • Don’t dispose of materials in the sink unless instructed to do so. • Wash your hands thoroughly. • Clean up all residue, and containerize it for proper disposal. • Dispose of all chemicals according to local, state, and federal laws. BE SAFETY-CONSCIOUS AT ALL TIMES

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