blood

Wording of this Handout:

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Have you ever wondered what blood is made of? Some people think blood is similar to sea water, but this is just not true.

If we compare blood with sea water, we find, for starters, that blood has much less salt in it. It also has more than 13 other big differences.

Sea water is no use to us as something to drink, except in very small amounts. Too much is poisonous!

Blood is made inside our bones - sea water is salty because the rain and rivers wash salt off the land into the oceans.

Blood is a fantastic substance, carrying air from our lungs to all our cells and taking carbon dioxide back to the lungs.

It also contains waste products and all sorts of chemicals which help to repair our bodies, and special cells which guards us against infection.

Just because blood has salt and water in it does not mean that blood and sea water are almost the same. In the same way, just because a loaf of bread has salt and water in it does not mean that it is alive!