Graphing Colors

So you've come to Ptolemy for a graphing activity. Who am I? Well, I'm an ancient Greek astronomer. One of my most important works of astronomy was compiling an encyclopedia of the heavens. In it I used centuries of Babylonian observations to map the stars and the planets, which I thought revolved around the Earth. Your graphs are not the same as the ones I used, but I think I can help you with a modern graphing activity.

Astronomers use graphs to sort information about the colors and wavelengths of light that they collect with their telescopes. In this activity we will be sorting colors too. This time, you will be sorting different colored objects of your choice.  Pull down the menu in this box
by holding the mouse button down over the arrow, then move the mouse to select something to sort:

Good choice! Do you see the group of  and the graph that I made for you?

Just for fun, try to guess quickly how many there are of each color without counting them, and write your guesses down.

Now take a look at the colors on the graph. Drag each of your onto the graph so that it is right above its color. Do this until all of your ALIENS are on the graph. When you're done, you should be able to tell easily how many  there are of each color.  How close were your guesses?

Make a picture of your graph in your notebook, and don't forget to draw the x-axis and y-axis (the axes). Write down how many  there are of each color.

If it's too hard to draw them, you can just draw a colored square for each one in its place on the graph.

Congratulations! You have completed your graph.
How do astronomers use graphs like this?  Go on to your next guide to find out and make your own graph.