Moving on from the *likelihood* of an event happening, today students focused on *experimental probability*, or the ratio of how many times an event occurs to the total number of trial attempts.

After some brief notes, we did a spinner experiment on the Smartboard. Smartboard has some great interactive components, one of which is a spinner that actually spins! Before actually doing the experiment, we talked about the theoretical probability of landing on a certain color. If we spin the spinner 5 times, it should land on each individual color 1 time each. Students understood that if we spun the spinner 20 times, it would then land on each color 4 times (ah, proportional thinking!) In experimental probability, we realized these chances are not always true.

I gave several students a chance to come up to the board and spin the spinner (which just involves “tapping” the spinner one time). They had a lot of fun trying to guess where it would land and would cheer when it landed on the color of their “bet”. (Watch out Las Vegas!)

20 spins with the tallies recorded, and students were ready to answer some questions on experimental probability. They worked in groups and then answers were put up onto the board.

## About Gretchen Simmerson

Middle School math teacher living in Austin, Texas.