October 2016 - You can see that leaves are only green because of the chloroplasts, because in the fall when the chloroplasts die, the leaves of the tree turn color and look yellow or orange to us. This is the color that the leaves are when they don't have any choroplasts in them. Go around your neighborhood in the fall and look at the leaves as they fall off the trees.
(Red is actually different: some trees actually make a special chemical to turn their leaves red in the fall. Nobody knows why for sure, but it's probably a kind of sunblock to protect the leaves from sun damage (by reflecting the red light). The undamaged leaves can finish transferring their leftover nutrients to the main tree before they fall.)
Look at the leaves on the trees. Which ones turn yellow first? Which ones stay green the longest? (The ones that get coldest at night turn yellow first, because the cold kills the green chloroplasts so the underlying yellow color shows through.
Collect some pretty leaves and bring them home. Put one under a piece of paper. Peel the wrapper off a colored crayon. On top of the paper, rub the crayon with the whole length of the crayon touching the paper, sideways, to show the veins of the leaf. Take some other leaves and put them between two sheets of wax paper. Put the wax paper between the pages of a heavy book, like a dictionary, to squash them flat and save them.
Bibliography and further reading about chloroplasts: