Laboratory Procedures and Techniques Notes

Be prepared to follow instructions carefully while handling materials.
Each participant should have a black rack for their lab items.
For your tubes:
- Pick up the tubes.
- Strap them securely.
- Place them in your designated black rack.
- There should be a total of four tubes.

Goggles must be worn when starting the procedure to ensure safety while handling projectiles or pipettors.
Confirm if everyone has finished labeling before proceeding.

Key piece of equipment: Pipette (specifically a P1000 pipette)
- Should read zero when set at 900, indicating 900 microliters (0.9 mL).
Note: Be cautious as caps may change.

Use proper pipetting techniques for accuracy:
- Press the button until you feel resistance (first stop).
- Release the button slowly while keeping the tip submerged in the liquid.
- Pull it out gently after releasing.
Fill all four tubes with the correct volume (900 microliters).
- Ensure each tube has similar levels of liquid for consistency.
- If excess water is present or incorrect techniques lead to different volumes, adjust as necessary.
- A drop discrepancy may be acceptable but aim for uniformity.

Avoid changing the pipette tip as long as you are using the same concentration and have not contaminated the tip.
- If tip comes into contact with anything other than the liquid being pipetted (e.g., other surfaces), change the tip.
After filling, dispose of the tip into the Lysol container to ensure cleanliness.
- Make sure to use the hard stop when releasing the liquid to ensure all is dispensed correctly.

Each pair of participants will have access to a balance scale:
- Turn on the scale using the power button (indicated by a circle and line).
- Allow the numbers to count down to zero before beginning.
Use a weigh boat for the soil sample:
- Utilize the tare function to ensure accurate weighing.
- Aim for one gram of soil, adjusting based on soil type (dry soil is preferred).
- If weighing exceeds one gram, carefully remove the excess.
Do not contact the inside of the weigh boat with fingers to avoid contamination.
Document all soil measurements in notebooks for future reference.

Once weighed, incorporate soil into the specified tube (orange cap tube).
Use a spatula for transferring soil if necessary, noting that scraping may be required based on soil consistency.

Use a vortex mixer for effective mixing:
- Hold securely and ensure the cap is tight to prevent spillage.
- Mix sample for approximately 5-10 seconds to ensure thorough integration of water and soil.
- After mixing, return the container to the work area if needed.

Only pipette into the orange tube once. Use different pipette tips as necessary for each sample:
- Close the lid of the tip box you are not using.
Change pipettes and tips as you work down the dilution scale, from the first tube into the second, maintaining accuracy in volume (100 microliters).
Maintain sterile conditions by only using each pipette tip once per sample to avoid contamination.

Mark each plate clearly on the bottom edge:
- Use initials and the date (e.g., February 10).
- Note: Transfer from tubes 2, 3, and 4 only, as specified in your procedure instructions.
Spreading the sample onto the plate:
- Place the liquid in the middle of the plate using the pipette.
- Use a cell spreader to evenly distribute the sample across the surface.
- Ensure plates remain upright for a minute before handling further.

Return all pipettor tips and equipment to proper locations after use to maintain organization in the workspace.
Ensure proper disposal of all lab materials in appropriate waste containers, particularly red cap tubes and soil samples.
- Confirm items are properly labeled and placed to prevent mix-ups.