WIKI                                                SOIL
 
 
 
SOIL COMPOSITION
Minerals by class http://mineral.galleries.com/minerals/by_class.htm
SOILS http://rain.org/~sals/balance2.html
BACKGROUND: Solid volcanic magma is loaded with nutrients, but it is such hard material that only a very few plants can get a foothold. The same is true of all igneous rocks. Plants grow in sediments, the rock that is broken down and weathered by water/ice and wind. Different rocks weather and erode to different kinds of sediments or soils. Good soils for growing plants are about half mineral, the rest is water, air and organic matter. The main soils are clay, silt and sand.

      SAND                              CLAY

The size of the particles give soils certain characteristics. 
Sand is composed of large particles. Sand drains water which means they are well aerated. It also means they are typically dry. They do not compact. 
Silts are smaller in particle size.
Clay is made of very small particles. It holds water very well, and in the water are dissolved minerals. However, clay readily compacts to the point where water and air cannot enter.


right click, select "view image" to view larger image

The proportion of clay to sand determines what kind of plants will grow best in a given area. The main concern is that terrestrial plants need to take up water, minerals and dissolved oxygen from their roots. Plants that grow in arid sandy soils have special adaptations of their roots for getting and holding water. The roots of this same plant would rot in heavy, waterlogged clay soils. Plants adapted to growing in clays would not be able to take up enough water in sandy soils to grow well. You will use a kit to test various soils for particle composition.  Loam is the term for a mix of soil types. 

MATERIALS: Your soil, 50 ml plastic tubes. 

METHODS: 

1. The basic idea behind separation is that sand drops to the bottom fast.  Silt takes a little longer (30 min) to drop to the bottom. Clay takes 24 hours or more to come out of solution. Put 15 ml of soil into the 15 ml line. Tap the soil down to make sure it has no air pockets.

2. Add 1-2 drops of liquid soap and fill the tube to the 50 ml line with water. Cap and gently rock for 2 minutes making sure that the soil sample is well mixed in.  REMOVE ORGANIC MATERIAL FROM THE TOP with your finger or a small plastic spoon that fits in the top of the tube.  Then add water to fill to the 50 ml line. 

3. Let the tube sit for 30 seconds, open the cap and carefully pour the solution into a glass being careful to not  dump the solid contents into the second tube. Read how much sand is left in the tube (solids A), record this, dump the sand out and rinse the tube out. 

4. Resuspend any settled material in the glass. Let this sit for 30 minutes. Pour the liquid off again into the glass. Record how much solids were left in the tube (solids B). Dump the solids and rinse, then pour the liquid back into tube. 

5. Let the liquid sit overnight or 24 hours. Pour the liquid off, record the volume of the solids (solids C). 

6. Calculate how much of sand, silt and clay there is. 

15 ml (initial volume of soil/solids)
subtract ml of solids A (sand)
subtract ml of solids B (silt)
subtract ml of solids C (clay) 

It should equal or be close to 15 mls!!

to calculate the volume,  amount you found X 100 = the percent for each 15 ml

Now look on the triangle chart and decide what kind of soil your sample is
RINSE AND SAVE THE TUBES, DO NOT THROW THE TUBES OUT, bring them back to class next time. 
 

In your WIKI

Create a TABLE for your findings. Be sure to LABEL your table. 
Write a results section that includes what kind of soil it is that you have tested. Make sure to identify the % of the total AND identify the fractions by type i.e. sand, silt or clay. 


 
GOOGLE AMBER
FOR FUN... 

What is amber? 
What kinds of fossils are typically preserved in amber? 
http://www.fossilmuseum.net/Tree_of_Life/FossilAmber.htm
How are amber fossils different than those in limestone?
How old can these fossils be?
Does amber contain DNA? Explain. 
Online, http://fgms.home.att.net/ambrfake.htm find out the difference between real and fake amber. 

Scenario: you are at one of Milwaukee's numerous festivals or at the state fair and you come upon a booth offering amber jewelry.  Which 2 tests could you use to detect faux amber?