Follow this procedure: Cut a piece four by six inches from the shirt
cardboard. Punch a small hole in the middle.
Break off a large, healthy leaf complete with its leaf stem (called a
"petiole")from the main stemofthe geraniumplaneInsertthe petioleofthe
leaf in the hole in thecardboard. Place thecardboardwith the petiole down-
ward over one glass,three-quartersfullofwater. Plug the hole in thecardboard
with vaseline to preventevaporatedwater from the lower glass fromcirculating
upward. Then cover the leaf with the second glass, so thatit rests on the
cardboard. See theillustrationbelow. Place this arrangementofglasses in
the sunlight.
You will observe:After severalhoursdropletsof water willappearon the
insideoftheupperglass.The green leavesofplantsgive off the water they do not needthroughthe
stomatesin theirundersurface. This process isknownastranspiration.HOW GRAVITY AFFECTS PLANT GROWTH
Materials:At least 10 bean, radish, pumpkinor sunflower seeds, two
smallwide-mouthedjarsor beakers (ten-ounce or pint-sized jellyjarswill be
fine), cleanblottingpaper,kitchenpapertowelling, string, some tap water.