This is a fun way to review the parts that make up blood.
Plasma
Makes up 55% of your blood. It's a thick liquid that carries that transports food and waste.Fill a clear glass/jar/beaker 55% full with corn syrup.
Make up 44% of your blood (by volume). These cells carry oxygen and carbon dioxide throughout your body.
Add candy red hots to the corn syrup, until the container is nearly full.
These cells are significantly larger than red blood cells, and there are far, far fewer of them in your blood. These cells clean-up old blood cells and fight the germs that enter your body.
Add a few mini-marshmallows or white jelly beans to your concoction.
Platelets
These are tiny fragments of cells (some books will just refer to them as cells) are responsible for forming clots when you are cut.
Shake some non-pareils into your blood model.
You now have a cup of "blood". You'll notice that much of it is liquid, but there's lots of solid in it as well. You'll also notice lots of red blood cells with the occasional white blood cell popping up. You have to look really hard to see the platelets - both because of their small size and because of their small numbers.
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and 
. They are less expensive, but I'm not sure how the size compares and I don't believe they include the instructions for getting the proper mass and color.
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