Bag of Beans - Contraceptives

In Health we begin our contraceptives unit today. In order to introduce the topic I have numbered bags of beans with different % of black and white beans. Students reach in and pull out a bean noting the color. After repeating that 10 times we calculate a % effectiveness. Once all of the bags were lined up, I revealed the actual percents and had them guess what we were leaning about. Contraceptives!