This is a fun activity to teach the students about probability and genetics. If you add up of the results from each of your classes the results comes out to be a 3 to 1 ratio nearly every time. All you need is a bunch of paper or plastic cups and two pennies for each student. Tell the teachers around you that your room is going to be noisy!! There are punnett squares on the back page also. The thumbnail generator messed up the appearance of the 2nd page, it doesn't really look like that! This activity supports Grade Seven California State Science Standard 2D - Students know plant and animal cells contain many thousands of different genes and typically have two copies of every gene. The two copies (or alleles) of the gene may or may not be identical, and one may be dominant in determining the phenotype while the other is recessive.