This file includes cards for the four main components of blood (red blood cells, white blood cells, platelets, plasma), brief descriptions to glue onto the back of the cards, a color poster, and a blank coloring page to paint.

Here is my suggestion:

Print and laminate the cards with the definitions on the back. Pair these with red water beads (red blood cells), ping pong balls (white blood cells), pokey shaped felt cutouts (platelets), and yellow water (plasma).

I like to have the coloring pages available with only a few colors and hang the example nearby to reference.

As another activity, I make a sensory tub full of the same materials for the children to fully explore.