Year 8 Science

Does a carrot have more starch than sugar?

On Friday, we had a science lesson with Mrs O’Meara. This term, we have been focusing on plants. We’ve been learning about things such as Dichotomous Key, germination, pollination, photosynthesis, and a few other interesting topics. This week we were looking at photosynthesis. As part of this we conducted an experiment to find out how much starch there was in various materials. The materials we tested were:

• Potato
• Onion
• Carrot
• Apple
• Flour
• Sugar
• Salt
• Paper

To conduct our experiment, we put one material in a beaker. Then, we would add around 4-5 drops of iodine solution to each material. If the material contained starch, the iodine would turn it a blue/black colour. Here were our results:

Material:	Colour with iodine:	Starch?               Yes/No
Potato	Black/blue	Yes
Onion	Yellow, tiny black dots on parts	A very small amount
Carrot	Dark orange/transparent, with some black	A small amount (approximately 1 gram)
Apple	Green/black/blue/yellow	A small amount
Flour	Black/blue	Yes
Sugar	Brown/yellow	No
Salt	Yellow/brown	No
Paper	Yellow	No

Here is a photopeach of our experiments:



What other materials do you think might contain starch? Conduct your own experiment and let us know in the comments below!

• Hattie and Kathleen