7C get testing

Today 7C did an experiment to prove the requirements for photosynthesis. 

They tested a leaf that was half covered with tin foil (no light on that bit)

They tested a leaf that had been on a branch that was in a bag with calcium hydroxide to absorb the carbon dioxide 

And a variegated leaf where the green bits had chloroplasts and the yellow didn't. 

They did the starch test on all of these

First boiling the leaf to kill it and remove the waterproof cuticle. 

30 seconds is enough

Then into ethanol to remove the chlorophyll 

After de colourising the leaves they were washed to soften them. 

Finally test with iodine 

They bits that go black have starch and those that stay orange don't. 

Which leaf was which?