SiSBoS Collaborative Graph

Kinematic Attic Notebook : Motion & Speed

Speed Graph

Choose Your X-Axis:

If you've been collecting speed data, you'll have noticed already that we don't all move at the same speed. What's causing the difference?

Does it have to do with how long you've been a citizen? Maybe you move faster if you've been around longer? If that's the case, by plotting each citizen's Whyville lifetime on the x-axis and speed on the y-axis, you would expect to see a pattern emerge, perhaps a line that slants up. If the graph is a complete mess, with no pattern to speak of, then there is probably no relationship between lifetime and speed. Remember though that even when you see a pattern, it only shows that there is a correlation. This might be the cause, but it's not for sure.

Use the drop-down menu to choose what data to plot the speed data against. Take a look at all the different possible causes we've suggested. Which one is correlated with speed? Post your thoughts in the BBS below.

What do you think determines how fast you move in Whyville?

A causal (not casual!) relationship is one in which one thing causes another to happen. For example, heat causes ice to melt. What are other examples of causal relationships?

A correlation is when two things have a tendency to happen or change together. For example, maybe you notice that every time your brother is upset, your cat disappears. It could be because when your brother is upset, he kicks the cat, so the cat has learned to make himself scarce. Or maybe the reason is that whenever your baby sister throws a tantrum, it upsets your brother and scares away the cat. The correlation you observe doesn't tell you enough to make any causal conclusions. What are other examples of correlations?

Once you've established what your speed in Whyville is correlated to, how would you go about testing if it actually determines your speed or if the two things are merely correlated?