lungs

these are our lungs. It is kind of like a sponge- it "soaks" in all
the oxygen from the air it breathed in. We made it by pressing bubble
wrap into pink paint (so it has the effect of a spongey lung, with air
pockets.)
Our heart sends blood in need of oxygen to our lungs. once the blood
has oxygen (plus nutrition/energy from food- but that will come later)
the heart pumps the blood to the body. That is why, while excercising,
our heart beats much faster. Because we are using the energy at a much
faster speed. So the heart needs to work twice as quick and twice as
hard to send fresh blood to the body. The fresh blood goes to all the
body parts through the arterys- red, the blue veins carries used blood
back to the heart. (someof us konw what the used oxygen is called- and
that it is good for the trees.)