Penny Magnitudes

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Penny Magnitudes

Create piles of pennies to represent the magnitude values of stars

Use pennies and a calculator to show the value of each magnitude category for stars. Star magnitudes are represented by six traditional categories. Category six represents the dimmest stars one can see without using a telescope. Category one represents the brightest.

Materials

A calculator, either hand-held or on the computer
Six paper dessert plates to model star magnitudes
Four rolls (200) of pennies (or paper clips or nickels or stickers or crayon marks, etc.)

Write magnitudes and calculator steps on each plate.
Magnitudes	Calculator Steps
6th	1 penny = _________ penny
5th	1 x 2.51 = _________ pennies
4th	1 x 2.51 x 2.51 = _________ pennies
3rd	1 x 2.51 x 2.51 x 2.51 = _________ pennies
2nd	1 x 2.51 x 2.51 x 2.51 x 2.51 = _________ pennies
1st	1 x 2.51 x 2.51 x 2.51 x 2.51 x 2.51 = _________ pennies

Look at the plates of pennies. Think about star magnitudes!

1. How many pennies are on the sixth magnitude plate? ________

2. How many pennies are on the first magnitude plate? ________

3. Which is dimmer, a fifth magnitude star or a second magnitude star? _________________________

4. Which is brighter, a second magnitude star or a third magnitude star? _________________________

5. How many times brighter is a first magnitude star than a sixth magnitude star? _______________

* Describe the magnitude scale for stars in your own words.

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* What new questions do you have about stars?

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** Try graphing your results. Place magnitude values on the X axis. Connect the plotting points with a curve. Put numbers by fives up the Y axis from 0 to 100. Describe the slope of this curve.

01/16/2000

* HOU™ Explorations *