Blood Typing Activity for Elementary and Middle School Aged Kids

Blood typing is an interesting topic to learn about, but can get a little confusing sometimes. 

Blood typing illustration from Exploring Creation with Human Anatomy and Physiology

First we read about blood typing from our text. Exploring Creation with Human Anatomy and Physiology does a nice job of explaining blood type antigens or markers as like flags on a ship, which declare for all to see where the ship came from. If an antigen that isn't yours is found on a red blood cell, your body will destroy whatever cells are "flying the foreign flag."

After getting the background information, we completed this easy demonstration that clearly shows which blood types are compatible and to whom. For this demonstration, you will need four clear plastic cups, some way to mark the cups (we used a Sharpie, but you could also use some Post-Its or the like), some red and blue food coloring and a way of being able to mix the two. I had an eyedropper and a glass slide on hand, but those are not necessary. You could just use another empty clear plastic cup to mix in, rinsing between additions. 

First mark your cups, "O", "A", "B" and "AB". Next put a few drops of red food coloring in the cup marked "A", a few drops of blue food coloring in the cup marked "B" and a few drops of each blue and red in the cup marked "AB". Do not put any food coloring in the cup marked "O". Fill cups about half-way with water.

Next we got a little of the receiver's blood type in a dropper and put a few drops on the slide. We then rinsed out the dropper with a little clear water. Lastly, we got a few drops of the donor's blood type in the dropper and added it to the blood type on the slide.

If the "blood" (colored water) on the slide does not change color when you add the "blood" (colored water) from the donor then that blood type receiver can receive the blood type from that donor. For example, if I put a little purple water from the blood type "AB" cup on the slide as the receiver and then add a little of the red water from the blood type "A" cup on the slide as the donor, the water stays purple. That means that "AB" blood can accept type "A" blood.

We filled out a chart as we went along, recording the compatibility results. 

This demonstration clearly shows that...
O can receive only O blood.
A can receive both A and O blood
B can receive both B and O blood
AB can receive all blood types and is the universal receiver.
O can donate to all blood types and is the universal donor as it can give to any blood type.

Older kids can reason it out once they see the colored cups of water, but may actually want to do the mixing anyway. Younger students may need to do the entire process.

Note: this experiment does not deal with positive and negative blood types but is meant only as an introduction to blood types.

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