Assignment 1: constructing a control

Almost any experiment you construct will require a control. Sometimes a positive control is needed sometmes a negative one is needed. your descision in selecting our control would depend on how you want to analyze your results.

A positive control would be an experiment you know would give you a positive reading. for example if you want to test if the leaves have starch you would have to have a test tube(TT) with starch already inside and tested with iodine. Any experiment with the same results as your control would mean that your experimental tube underwent the same reaction as the control

A negative control would be an experiment in which you know would give you a negative reading. This is what we call a baseline reading . for example, a negative control for assignment 1 would be a TT with just dH2O inside. The whole point of a negative control would be to allow you to get a net reading (ie a reading due purely to your experiment)

example:
if you place a yeast-glucose suspension in a syringe and immerse it in a waterbath at 30 C and obtain 25 bubbles per min.
Then place a negative control containing boiled yeast and glucose in the same waterbath and count no. of bubbles. (maybe 2 bubbles per minute)

net production of bubbles would be 23 bubbles per minute. You can then speculate that te other 2 bubles are due to some error (depending on the Q you may have to identify source of error)

In assignment 1 you have to decide what methodology to use with an appropriate control.

For example if I want to examine amount of starch produced by weight, I may need some leaves in a situation in which starch cannot be produced.(maybe place leaf disks in the dark or in dH2O )


Next: Analysing your results