1. Testing foods for starch.
Circle the laboratory instruments you will need for this experiment.

2. Next to each name draw a sketch of the instruments above.
Test tube
Wash bottle
Beaker
Test tube rack
Dropper

3. BACKGROUND INFORMATION Starch is a carbohydrate. It is found in plants
BACKGROUND INFORMATION Starch is a carbohydrate. It is found in plants. Green plants make carbohydrates through photosynthesis. Starch is therefore in many foods, but also in other things as well, e.g. some paper. Starch is a white powder. Starch reacts with iodine to produce a blue or blue-black colour. It can therefore be used as an ‘indicator’, i.e. to test if starch is present in something.
TRIGGER QUESTIONS:
1) Where do you find starch?
2) Where do you think starch comes from?

4. Equipment
Test tube, beaker, glass rod, dropper,
wash bottle, test tube rack
Materials
starch, potato, wheatmeal;
iodine solution;
distilled water.
Procedure
1) Add 10 cm3 of water and some starch to a clean test tube. (Our sample)
2) Add 10 cm3 of water and some wheatmeal to a clean test tube.
3) Add 10 cm3 of water and some sucrose to a clean test tube.
4) Peel off the skin of potato.

5. Did iodine turn blue or blue-black? Was there starch in the item?
Activity
5) Add a few drops of iodine solution to each of the items and observe the change of colour of the iodine (if any). Anything that turns blue-black contains starch.
Record the results in a table:
ITEM
Did iodine turn blue or blue-black?
Was there starch in the item?
Wheatmeal
Sucrose
Potato