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Procedure

1. First take five empty test tubes and arrange them in a test tube rack

2.  Second take a pipette attached to a disposable pipette pump (in this picture green and white) and take out of the jug of distilled water 10 milliliters for the first test tube and 9 milliliters for the other four

3. Next take a soil scoop and fill it with the soil that you are testing

4. Then shake/tap/dump the soil in the scoop into the test tube with 10 milliliters in it

5. Cap the test tube and shake until the soil is well mixed with the water

6. Then with the same pipette that you used to fill the test tubes, take 1 milliliter of the mixed soil from the 10 milliliter tube and put it into the first 9 milliliter test tube and shake this one (continue to take 1 milliliter from each test tube and shake)

7. This is what your test tubes should look like, from left to right 1st test tube with the soil scoop in it, 2nd tube with the 1 milliliter of water and soil from the 1st (shaken), 3rd has 1 milliliter from the 2nd (shaken), 4th has 1 milliliter from the 3rd (shaken), and 5th has 1 milliliter from the 4th (shaken) (Note: when you are finished with your disposable pipette throw it away so that you do not contaminate the next batch of dilutions, get a new pipette)

8. Take our your labeled petrifilms and arrange them in order. Then take a micropipette and open the tip box and get a tip (close the box as soon as you are done with it so as not to contaminate the rest of the tips)

9. Take micropipette and fill the tip with the liquid (do not let the liquid touch the white part of the pipette) from the 1st test tube and put it on the appropriately labeled Petrifilm (Note: place the liquid close to the center of the Petrifilm so that when you spread it with the 'spreader' the water doesn't spill over and out of the Petrifilm)

10. Place the cover of the Petrifilm over the liquid to 'seal' it

11. Take the 'spreader' and place it on the liquid so that the liquid spreads around on the Petrifilm

12. Take the tip and eject it into a beaker with bleach in it (when this beaker gets full put on a latex glove and throw away the used tips)

13. Place all of your dirty test tubes, soil scoops, and test tube caps in soapy water

14. After scrubbing the test tubes, caps, and soil scoops place them in clean water to rinse out the soap