Learning in the Lab!
Questions for today:
Why do we test soil? What is a pH value? How do we measure conductivity?
This morning we stayed in the lab to work on all the soil samples we have collected from three different sites: the Fen, the Tundra and the Tree Island. We took samples from 3 depths: 1-10 cm, 10-20 cm and 20-30 cm deep. Will be soils be the same or different?
In each sample we want to find out 5 things for soil at the different depths we collected.
1. The amount of moisture each sample had. We weighed the soil before and after we dried it in an oven at 105°C for 12 hours.
2. Then we burned the sample in a Muffle oven (550°C for 3 hours) to figure out how much organic matter there was in the soil. This told us how much carbon was present in that sample . This is important because it tells us how much carbon can be released in the atmosphere if the permafrost melts and there is more decomposition of the peat around the world.
3. What the pH value of the soil it. We made a mud paste in a small beaker and put an electric probe into it. Soil pH is a measure of acidity or alkalinity. An acid solution has a pH value less than 7. Many plants and microorganisms prefer either alkaline or acidic conditions and the pH can affect the availability of nutrients in the soil. (There is a great game link at the bottom of this post)
4. What the conductivity is. This tells us how much salt is in the soil, thus again giving us another characteristic of the soil system. We put a mud paste in a test tube and put a probe into it.
5. The color of the soil based on the Munsell Soil identification chart. This is an internationally agreed upon table to describe the colors of different soils.
Math Connection for the day: Excel, Excel, Excel. This is an extremely important program to understand how to use and the younger you start the more you can learn all the different ways it can help gathering and looking at data.
Visit The Alien Juice Bar to learn more about pH while you play an interactive game! http://sv.berkeley.edu/showcase/flash/juicebar.html