# Ball Mixing Activity: 2 Balls - 3rd-6th grade probability (NOW: InterActivity)

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Then, double-click on 2balls.html. How do I do all this?

Scratch file designed by Linda Fahlberg-Stojanovska.

Activity Notes

We have 2 balls - 1 Red and 1 Green. We mix and drop them into a vertical box. What color ball drops first?

The following two events are mutually exclusive and complete.

 (a) The green ball will drop first.  We call this event: Green first. (b) The red ball will drop first.  We call this event: Red first.

Guided Activity

Do the experiment 200-1000 times.

• What is the percent of green first?
• What is the percent of red first?

Now for some dreaded theory ...

• Theoretically, how often should the green ball drop first into the box?
• Theoretically, what is the probability that the red ball will drop first?
• Does this agree with your experimental results?
• What other real life situations give this kind of probability?

"Mutually exclusive" means both events cannot happen at same time and "complete" means no other event can occur.