Student can instruct a simple Plinko board with large-head nails, a smooth board and some colorful disks or poker chips. Carefully measure and determine the distance that needs to be between two nails to allow the poker chips to drop through. When the exact distance is determined, carefully mark the board to indicate where all the nails should be placed. Then hammer the nails carefully into the center of each marking. After the first few nails, attempt to drop the poker chips again to make certain that the spacing is exactly correct. There should be between six and 10 possible places for the chip to drop out at the bottom. The game is played by dropping a poker chip from the top of the board, where it will choose its own path as it bounces off the different nails. If built properly, there will be no way to predict which opening at the bottom the chip will come out of. Students should calculate the probability of the different possible outcomes. They can number the open slots at the bottom, and if they create six openings, have them determine that the probability of any possible ending point will be 1 in 6, or 17 percent. If they create eight openings, the probability will be 1 in 8, or 12.5 percent, etc.
A simple probability game for two students to construct is to take a large rectangle of Styrofoam and stick lollipops into it. The lollipops can be arranged in 10 rows of 10. Mark each lollipop stick near its end with a bright marker. There should be different quantities of each color. The lollipops should be pushed far enough into the Styrofoam to hide the colored markings. Students will determine the probability of picking out one of several possible colors. Students can choose the number of different colors there should be and how many there should be of each color. Students should calculate the probability of the different possible outcomes with their partner. For example, if there are 100 lollipops, and 20 of them are red, then the probability of drawing a red is 2 in 10, or 20 percent.
This game might be a bit more fun with oversized dice, but can be played with traditional small dice as well. To make it challenging for middle school students, have them calculate the probability of not only total sums of the dice i.e., "rolling a 10," but of particular combinations, as in "rolling two fives." To make the game even more challenging, three or more dice can be used. Students can create a fun, decorated "arena" to roll the dice in, using the lid of a dress box or something similar. Students should calculate the possibility of the possible outcomes, for example, if there are two dice, the probability of rolling a 3 is 2 in 36, or 5.5 percent. (Of the 36 possible outcomes when rolling a pair of dice, two of those outcomes would result in a sum of 3). The probability of rolling two threes is 1 in 36, or almost 3 percent. (Of the 36 possible outcomes when rolling a pair of dice, only one of those outcomes is double threes.)
Simple spinners taken from other board games, created by the students out of card stock and metal brads, or purchased at a teacher's supply store, offer many possibilities for probability games. If a spinner has eight places each marked with the numbers 1 through 8, have students calculate the probability of landing on a certain number when they spin. The probability of any possible outcome would be 1 in 8, or 12.5 percent. Then, have students calculate the probability of landing on an even number, which would be 1 in 4, or 25 percent. Have students come up with ideas for other things they can spin for and have them calculate the probability of each possible outcome. Spinners can also be created with colors or symbols in the slots.