Materials needed: well plate from last week, plastic pipets, fluorescence cuvettes with caps, fluorescence spectrometer, kimwipes

1. Remove the plastic lid off the well plate. Be careful not to allow condensate to spill back into the wells, as this will adversely affect the fluorescent readings. The solutions may have settled and you'll see a 'lawn' of algae on the bottom of the well plates; re-suspend your algae by drawing the well's solution up and down using a plastic transfer pipet. You can also use the tip of the pipet to gently scrape the algae off the bottom of the well.

2. Transfer approximately 1.5 mL of each solution into fluorescence cuvettes and cap them. Use a different pipette when transferring each of the different solutions because they all contain different concentrations of algae.

3. You will be taking fluorescence measurements. Several minutes before that, gently invert the capped cuvettes containing your algae solutions. Wait approximately one minute for the solution to stabilize before proceeding. Use the fluorescence spectrometers to locate an emission peak near 465 and 685 nm. It is easiest to measure one peak at a time for all solutions, then switch peaks and measure the solutions again. Record the counts at both your emission wavelengths (465 and 685 nm) for each of your samples.