Good Research Question must have IV, DV, well defined, focus and DV must be measurable.
If possible try to use Vernier Lab Pro for Quantification.
Vernier LAB Pro VISIBLE SPECTROPHOTOMETER FOR QUANTIFICATION
How will changing concentration of alcohol affect the rate of diffusion of beetroot pigment measured by the change in absorbance using a visible Spec in a beetroot experiment ( Beetroot with alcohol )
How will changing salt concentration affect the change of absorbance due to formation of blue black on amylase activity in a an amylase starch solution measured using Visible spectrophotometer.
Below are 2 samples done using Vernier Lab Pro ( Visible Spectrophotometer ) for quantification.