Discovering Blood Type Compatibility

This is a great science project for younger kids, to introduce them to how blood types work. There are four different blood types, and this experiment shows kids that some types are compatible, while others aren’t.
While supervision will be required in case things get messy, this is an inexpensive and easy project to do.
Materials List:
  • 16 Cups to put water in
  • Pencil or pen & paper
  • Blue food coloring
  • Red food coloring

Instructions:

Put an equal amount of water in each of the 16 cups. This doesn’t have to be a lot of water, but enough to pour some into other cups and still have some that you started with.
Once all the cups have water, leave four of them with plain water. Add red coloring to four of the cups, blue coloring to four other cups, and add both red and blue coloring in the last four cups to make purple water.
Make sure your child writes down that the red water represents Type A blood, and that the blue water represents Type B. The purple water will be used to represent Type AB, and the plain water represents Type O.
Then you start adding some of the water to other cups. In order to keep things organized, it’s probably easiest to start with adding water from an “A” cup into another “A” cup. The color of the water will not change, which means that Type A blood is compatible with Type A for transfusions.
You will get the same result adding “B” to “B”, “AB” to “AB”, and “O” to “O”. You can either do all of these at once, or stick with each blood type and add it to all the others before moving on to the next.
Then add an “A” cup to a “B” cup and let your child witness what happens. Since the color of the water changed from blue to purple, they can know that Type A and Type B blood are not compatible for transfusions.
Repeat these steps with all the different colors, and make sure that your child is making notes on the reactions of all the different “Types.”
The experiment will end with these results: Type A and Type AB people are the only ones that can have Type A blood. Similarly, Type B and AB people are the only ones who can have Type B blood. Type AB people may have any blood but they can only give blood to other Type AB people. And finally, Type O people can give blood to anyone but they can’t take blood from anyone but another Type O.
Interested in other things about your body? Did you know that we have a blind spot? Find out more about Blind Spots here.