The youngest is learning about the human body this year. In the past, we've done a lot of experiments with the human body, but this one experiment was really fun learning about blood types. Here is another activity we've done on blood: http://meanttoteach.blogspot.com/2014/04/blood.html I'll eventually get a chance to group all of our human body activities because I have more on my blog. There are 4 blood types: O, A, B, and AB. We discussed what a donor was, what a receiver was, and why it matters for doctors to know if the blood types are compatible when someone donates blood. We talked about antigens and how a patient could become very sick if their body rejects new blood. This experiment was simple. All you need is: Two colors of food coloring (Red and Blue work best, but I only had yellow and blue. So that's what we did.) Water Dry Erase Marker 1. Fill each cup halfway with water. 2. With the dry erase marker, label each cup with one blood type. 3....