Lab 8 Biology You will serially dilute a known mass of soil, make agar plates of

1. Lab 8 Biology You will serially dilute a known mass of soil, make agar plates of the dilutions and estimate the number of microorganisms in the original mass of soil by counting the number of colonies on selected agar plates and multiplying by the dilution. Easy. Kind of fun but makes you use the old bean. Plus you can take the incubated agar plates home if you like. These are the dilution bottles The first one (10-1) has glass beads to help disperse the soil you add.

2. Add soil to first dilution bottle and shake to disperse Since you used 10 g of soil and there are 90 mL of (sterilized) water in it to begin with, every 1 mL of the suspension contains 0.1 g of soil, hence, it is the 10-1 dilution. Take 10 mL of it and transfer to the next dilution bottle to give the 10-2 dilution and so forth on to 10-7

3. Pipette 1 mL of specified dilutions to petri dish, add agar, swirl and incubate 1 week