ACTIVITY: Cosmic Scales





Answer the following questions about scales (the objects in the blanks will be given in class):


1.    If one edge of cube A is __5__  times longer than one edge of cube B, and one edge of cube B is ___7__  times longer than cube C (exhibited on front desk),  then how long is one edge of cube A?  Would it fit in the classroom?

3500 mm (320 cm) i.e. factor 1 x factor 2 x cube C length



2.    What is the volume of cube A?

(factor 1 x factor 2)3x(100 mm)3=4.2875x1010 mm3


3.    What is the diameter of the marble? What is its radius? What is its volume?

16 mm

8 mm

(4/3)p x (8 mm)3 ~ 2145 mm3


4.    About how many marbles would fit in cube A? (Disregard the effects of air gaps between marbles.) Considering the accuracy of your ability to measure the size of your marble, what might be a more realistic guess for how many marbles could fit in cube A?


2.0x107 = 20,000,000


5.    What is the ratio of diameters between the planets ____Venus_____ and ____Mars_____? Suppose the marble you were given in class represented the size of the planet __Venus___.  What diameter (mm) marble would be required to represent  the size of the planet___Mars__?


marble diameter (mm)/1.78 = 8.98 mm~9.0 mm


6.    Estimate how many people set end-to-end would reach from the Earth to _____ the Moon____ ?  Do we have enough people in __the U.S__ to do this?

200 to 250 million



7.    Rewrite your first answer from question #6 in scientific (exponential) notation.

2.0 x 108 to 2.5 x 108


8.    The distance from the Earth to the Sun is 1 Astronomical Unit (AU).  What is the distance from the Sun to ___(current position of) Voyager 1__ in AU's?  Give Voyager 1 distance to students= 20,570,000,000 km . 1 AU = Find in Appendix A

137.5 AU


Open the web site
and click “START.” Notice the grey ring that is 1 meter in diameter.


9.    Slowly drag the slider near the bottom of the screen to the left until you see another circle appear. What size does this circle represent?

10-3 m = 0.001 m = 1 mm


10.  Drag the slider to the left, until another ___   _5______ grey rings appear; the number in the lower-right part of the screen should be ___  10-15______. What objects are approximately this size?

Proton or neutron


11.  Drag the slider to the right, until the number in the lower-right part of the screen reads ____106______. What is the smallest astronomical body just outside the grey ring?



12.  Drag the slider until the number in the lower-right part of the screen reads 1019.4; you will start to see the smallest galaxies. Continue moving the slider to the right until you see __ The Milky Way _____. How large is it in meters?

1021 meters (Zettameter) or 1.2 x 1021 meters (if clicked on)