Showing posts with label experiments. Show all posts
Showing posts with label experiments. Show all posts

Saturday, November 24, 2007

Marble Run

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This weekend we've been playing a lot with my marble run. I really enjoy filling it completely with marbles.

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Daddy and I also like to do a version of mythbusters with the marble run. The latest myths we've been studying involve these two "Y" sections of the marble run, where the marbles can either go to the left or to the right. The way the marble run is formed, there's a "Y" early in the run and a "Y" later in the run. The marble has to pass through both Y's to land in the red or green bins but only the first Y to land in the yellow bin. The myth is that the marble is equally likely to land in any of the three bins. We busted that myth--a marble is more likely to land in yellow than either of the other two bins. We also checked that the Y's are "fair" in that the marble is just as likely to go left as right. So, how do you solve this mystery?

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Saturday, March 03, 2007

Aidan Morgan: Teaching Assistant

I helped with Daddy's class today. It seems that his class is playing the OPEC game and a coin flip determines whether the game continues. Check out how I determined the results for market A here and market B here in two short videos Daddy and I made.

Monday, October 23, 2006

Signals and Noise

I love to do experiments. As you know, I started experiments at a very young age--2--when I got to do some sinks versus floats experiments. Since that time, I've done lots of other experiments. Here is the most complex experiment I've done yet. It's called signal versus noise.

To do this experiment, you need poker chips in three different colors. I have red, white, and blue chips. You make two stacks of chips. One stack contains 2 blues, 1 red, and a variable number of white chips. The other contains 2 reds, 1 blue, and the same number of whites. The experimenter then decides which stack to put in the "urn" (my pumpkin basket) and which to hide in a nearby drawer. The other person, then draws chips from the urn, records their color on the data sheet, and then puts them back. After 5 draws, the goal is to guess whether the urn contains 2 reds or 2 blues.

When there are no white chips, it's not that hard to guess correctly. If more reds come up, you should guess red. If more blues come up, you should guess blue. Adding white chips makes things more interesting. The white chips are "noise"--you don't learn anything about the reds and the blues from the whites. After a bunch of trials, Daddy and I learned the following.

The more white chips there are in the urn, the more data you need to make a correct guess. We tried drawing 5, 7, 9, even up to 20 times and making guesses. It gets pretty hard when there are a lot of white chips. The more noise, the harder it is to guess correctly.

Now, for an even more surprising experimental finding. We tried the following comparison. 2 red, 1 blues and 6 whites versus 1 red, 2 blues, and 4 whites. Interestingly, when the number of whites is not the same in the two stacks, you can use the "noise" (the whites) to guess whether there are mostly reds or mostly blues. Amazingly, even without seeing any reds or blues, you can make a good guess. For instance, suppose you draw 7 whites and nothing else. We learned that this is a good indication that the urn contains mostly reds since there are more whites when there are more reds. Daddy says that this is because the whites are "correlated" with the reds.

This is maybe the coolest experiment ever!

A postcript: I've started thinking up and designing more of my own experiments. Yesterday's experiment asked the following question: Do you get more soap bubbles when you add the soap before adding the water or after. To conduct this experiment, I got two identical Dixie cups. In the first cup, I put in one squeeze of liquid soap, filled to the top with water, and observed the number of bubbles. I then filled the second cup to the same level and added one squirt of liquid soap after it was filled. I observed that the second cup had a lot fewer bubbles than the first.

Conclusion: Soap first produces more bubbles than soap added after.

Daddy was very impressed at the quality of this experimental design.