Positive control = starch, what is the negative control? - (Oct/31/2014 )

Teacher want's us to choose a negative control for this and I have no Idea.

1. Set up a positive control for this experiment by spraying a paper towel with the starch solution. Allow the starch to dry for approximately one hour (this time interval may vary by local humidity).
2. In the mean time, set up a negative control for this experiment. Use your knowledge of the scientific method and experimental controls to establish this component (hint: what should happen when IKI solution contacts something that does not contain starch?) Identify your negative control in Table 1.
   Note: Be sure to space the positive and negative controls apart from each other to prevent cross-contamination.

the full experiment can be found here:

EXPERIMENT 1

http://www.scribd.com/doc/235748215/Lab-4-Answer-Sheet1

so your negative control should be something that doesnt have starch, right? first find, what is starch? then you can easily find the negative ctrl.

 think very basically what all does/doesnt have starch, start from water, does it?  meat does it? or vegetables ? plastic ? ask yourself you can find it.