
Marbles and the Bell Curve
Medium
Can you predict where a marble will land after bouncing through a grid of pegs? You build a pegboard device with 12 compartments along the bottom. A funnel at the top drops marbles onto wooden dowels that deflect them randomly.
You release 200 marbles at a time. About 50% land in the two center slots. Around 34% split across the three slots on each side. The remaining 16% reach the two outermost slots on each end.
This pattern repeats within 5% on every trial. The results form a bell curve, and you can predict the spread before each drop.
Hypothesis
The hypothesis is that the probability of the marbles falling into each compartment will follow a bell curve.
Method & Materials
You will construct a device with 12 compartments and drop marbles from a funnel at the top.
You will need a 1 foot X 2 foot piece of pegboard, 12 one inch slats, wooden dowels, and marbles.
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See what’s includedResults
The experiment showed that the probability of the marbles falling into each compartment followed a bell curve. The results were consistent within 5% each trial.
Why do this project?
This science project is interesting because it shows how a bell curve can be used to predict probability.
Also Consider
Experiment variations to consider include using different sizes of marbles or different sizes of compartments.
Full project details
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