edgesofsome leaves aresmooth,otherare scalloped. Stillothersarejagged,
or cut up like teeth.
The kindofleaf a tree bears, its type ofvenationand thecharacterof
a leaf'sedge all help to identify the type of tree on which the leaf grew.
HOW AGREEN LEAF PRODUCES FOOD- PHOTOSYNTHESIS
Materials:A leaf from a silvergeraniumor a coleusplant,a double boiler,
a solution of dilute iodine (iodine mixed with water), a small amount of
alcohol, a saucer, a forceps or an old kitchen spoon. Forthis experiment,
you will have to use the kitchen stove, but be sure to get yourmother'sper-
mission first.
If you are luckyenoughto own an alcohol burner,you can use it for this
study-alongwith a ringstandand an asbestos pad.
Follow this procedure:Fill thebottomof thedoubleboiler withhotwater
andbringit to a boil. Place ageraniumor a coleus leaf in the top of thedouble
boiler and cover it well with alcohol. Remember,though,sincealcoholburns
quickly, you must neverputa containerofalcoholdirectly over a flame!
Set thetopof thedoubleboiler over the boiling water in thebottompan.
Aftera few minutes-assoon as the leaf loses its coloration-turnoff the
flame. Then, using your forceps or spoon, remove the leaf and putit on a
plate. (Ifthe leaf is still green,returnit to the top of the double boiler and
heat a fewminutesmore.)
Wash the boiled leaf carefullyunderslow-runningtap water. Lay it flat
on the plate andpourdilute iodine over it. After a fewminutespouroff the
iodine and wash the leaf again in tap water. Clean the plate.