Preschool Biology—What Blood Does in Our Body

Has your preschooler ever skinned his knee so badly that it is bloody? It may upset your preschooler to see the blood, but the blood coming out of the wound is a good thing. It helps clean out the wound. You then put a bandage on it and some antibacterial cream and it heals in no time. The healing qualities of blood are just one it's purposes in our body. Blood is also the basis for our body’s temperature control. Your preschooler is likely not aware of how much blood moves through his body. Here are two experiments that will make your preschooler more aware of one of the main purposes of blood in our body--temperature control. It will also teach your preschooler how to warm up quickly when he is cold.

 

 

Have your preschooler sit still for a period of time, until he feels that he is cold or have him sit in a cool room with a short sleeve shirt. Once your preschooler feels cool or cold, have him go to a sink and turn his wrists over so that his palms are facing upward, exposing the arteries. Point out the arteries to your preschooler. Explain that arteries carry blood away from your heart. Then turn on warm to hot (but not burning hot) water and place your preschooler's wrists under the water. Your preschooler should begin to feel warmer in a few minutes. Why? This happens because you are heating up blood that is circulating in your body. This is the same reason why you drink hot liquids on cold days. A cup of hot cocoa will warm you from the inside out while the hot water will warm you from the outside in.

 

 

In the same way, have your preschooler sit still for about 30 minutes and become cool. Once your preschooler is cool or cold, ask him to jump up and down for 30 seconds. When your preschooler is done ask him if he feels warmer. If not, have him run in place for another 30 seconds. Ask again if you preschooler feels warmer. Eventually your preschooler’s threshold will be reached and he will become warmer. Explain to your preschooler that movement makes us warmer because we are increasing the circulation of blood in our bodies by moving around. Increasing your circulation makes you warmer.