What to do, what to do, what to do...

I still haven't completely decided exactly what experiment i'm going to do, but so far i really like the idea of involving soft drinks/energy drinks in my experiment. Right now i've got 3 experiments in mind....

1. How energy drinks effect reaction time in humans
2. How energy drinks effect memory in humans
3. Comparing how much fizz is created by shaking different soft drinks*

1. If energy drinks effect reaction time in humans

If i were to conduct an experiment to find out how energy drinks (e.g. 'Mother','V','Red Bull') effect reaction time in humans, i would probably use the ruler experiment conducted in science class last year during the co-ordination topic. It involved a centimeter ruler(vertical) being dropped just above someones open (palm facing sideways) hand, the amount of centimeters revealed at top of hand (cm = dependant variable) would indicate reaction times. I conduct this prcedure twice before the energy drink is taken, then twice ten minutes after the energy drink has been taken for an hour(unsure of time, maybe 40 or 50 mins)(time = independant variable). After all the results (cm) are recorded i will probably use a line graph to show the relationship between the human reaction time before the energy drinnk was consumed, to human reaction time after the energy drink was consumed. The hypothesis is a bit dodgy at the moment but in a nutshell would probably be something along the lines of:

"Energy drinks cause reaction times in humans to increase for approx. 40 mins after consuming, then decrease at a faster rate then it's increase."

This is my first choice as their seem to be less variables in this experiment compared my second and third options.
NOTE - Not sure if activites between ten minute intervals will effect reaction time and if it does it may be difficult to find a large amount of people willing to sit still for an hour (especially if they've to drink an energy drink)

2. How energy drinks effect memory in humans

This experiment would probably be conducted in the same way as the first experiment option, 'If energy drinks effect reaction time in humans', in regards to usiong time as the independant variable and testing the dependant variable twice before drinking the energy drink then twice at ten minute intervals for an hour. I then plan to read out a series of of numbers to see how many the victim (i wasn't sure what to call the person being experimented on) can recall (the amount of numbers recalled would be the dependant variable). The results will be tabulated then put into a line graph. As for the hypothesis, it would basically be the same as the first experiment options hypothesis, structure-wise:

"Energy drinks cause memory efficiency in humans to increase for approx. 40 mins after consuming, then decrease at a faster rate then it's increase."

* my third experiment idea is probably not going to be the one i'm going to choose, although it is preferable(aka FUN!), there would be too many variables (shaking during delivery from manufacturer to store, shaking at different strengths etc.)