need to know


Carbon Dioxide + Water → Food (glucose) + Oxygen


Chlorophyll is the Chemical that makes leaves green

investigation of the conversion of light energy into chemical energy

What chemicals does a plant take in to grow?

What else does a plant need to grow ?

What does the plant give out?

What does it make for itself?

Where does the plant take in the water ?

Where does the plant take in Carbon Dioxide?

Light hits leaves and makes food with a green chemical called _______

Carbon Dioxide is taken into the plant through the leaves.

It enters on the underside of the leaf, through little openings called stomata

Count how many H's, C's and O's there are on each side. Is this equation balanced?

So lets fix this equation ... Balance the Hydrogens then the carbons and finally the oxygen!

Do you remember the chapter / section on digestion ?

Do you remember that Humans convert starch into sugars ?

Where did this happen ?

You might see that animals and plants are opposite each other, they need us and we need them.

This is a symbiotic relationship !

Plants make the sugars and convert them into starches for storage ....

can you remember how to test for starch ????

Iodine is the test for starch

What might be the problem with checking a change in colour in a leaf ???

A leaf is Green, and it will be hard to see the colour change

ÒB49 show that starch is produced by a photosynthesising plant


Green Plants, Tinfoil, Sellotape, Hot Plate, Beaker, Test Tube, Methylated Spirts, Iodine, tongs, tweezers


Place the Green Plant in a dark press, the plant will use up its' food reserve from its leaves.

After a few days of no light, observe the plant.

Ask yourself, Has its appearance changed ?

Take a thin strip of tin foil and wrap it about a leaf. Be sure to leave some of the leaf in light while blocking the light from another part of the leaf.

Gather 3 leaves, from the plants we prepared in the last class.

1 from each of the plants in bags, and one from the leaves covered by the foil. It is these leaves that we are going to test.

Label a Boiling Tube with a sticker, with your name, describing the recent conditions of the particular leaf, each person in the group should take charge of one leaf.

Set up a Tripod and Bunsen, to boil water in a beaker.

Using Tongs place each leaf in the Boiling water for 4 mins.

After, place the boiled leaf in to a tube of Methylated Spirits.

Carefully Using Tongs place the tube with the leaf and spirits in the water that was boiling for 10mins or until the leaf turns white.

Remove the tube from the hot water

Take the Leaf from the tube, using tweezers or similiar.

Rinse it in warm water. Spread it out on a white tile.

Apply Iodine to the leaf using a dropper

What do you see?

Do you think your leaves contains starch?



Where the leaf is stained Dark Blue, shows where starch was made. Where the leaf does not stain dark blue no starch was made. No starch was made where the tin foil blocked out the light.


Plants Need Light to Make Food!


the alcohol evaporated overnight

It was hard to see the starch