Q: How do I use my soil pH meter?
A: Soil pH meters come with instructions that you must read carefully and follow closely to collect accurate data. Every soil pH meter may be slightly different, so it is important to read and follow the directions. Here is an overview about how to use the RapiTest Digital Soil pH meter in the Science Buddies kit:
- Press the Power Button to turn the meter on and off. When you turn the meter on, its default reading is 7.
- To measure soil pH, slowly add tap water to the soil in the sediment tube until the soil is damp, but before water starts to pool on the sample's surface.
- Use the green pad that came with the meter to shine the long, narrow probe of the meter, but not the bullet-shaped tip. Use a facial tissue or cotton ball to wipe the probe from tip to handle.
- Gently put the probe in the soil in the center of the sediment tube.
- With the probe in the soil, twist the meter back-and-forth so that soil can attach to the probe. Twisting the probe is important to getting accurate measurements.
- Wait for 60 seconds. Then,
- If the pH is above 7, remove the probe, clean it with a new facial tissue or cotton ball, shine it with the green pad, re-insert the probe, and wait for 30 seconds. The measurement you read after 30 seconds is the pH of the soil. Record this in your lab notebook.
- If the pH is below 7, remove the probe, clean it with a new facial tissue or cotton ball, do not shine it, re-insert the probe, and wait for 30 seconds. The measurement you read after 30 seconds is the pH of the soil. Record this in your lab notebook.
Q: I am always getting a reading of 7 from my soil pH meter. What should I do?
A: If you are always getting a pH reading of 7 it is probably because you are not using the pH meter correctly. Re-read the instructions that came with the pH meter and make sure to follow them exactly. For the meter included in the Science Buddies kit, not twisting the meter and not waiting for the appropriate amount of time are the most common causes of a constant pH 7 reading.
Q: The filter in the runoff-filtering containers ripped, and unfiltered water or soil fell into the container. What should I do?
A: This is an easy problem to solve. Create a new runoff-filtering container and simply re-filter the water.
If you have other questions about the procedure or need assistance troubleshooting your project or the Experimental Procedure, please post your question in the forum for this kit at Ask an Expert: http://www.sciencebuddies.org/science-fair-projects/phpBB3/viewforum.php?f=74. Our team of volunteer Experts is available to assist. We attempt to reply to questions within 24 hours. Please note that you will need a free Ask an Expert account in order to post questions.