Note – Your sample numbers should consist of your group number + a one letter symbol indicating whether the source material is from soil (S) or plants (P) + 1 sample number.  An example sample number would be 13C-P1.

 

This activity is designed to give you practice in collecting and preparing samples for neutron activation analysis.  All data should be recorded in a data table similar to the following:

 

 

You will record all data except Dry Mass and % Water Content today.

 

Each group should collect two soil samples from near the creek and two plant samples (for the purposes of this activity, choose Himalayan Blackberry) near the soil sample locations.  Make sure to cover your soil holes after the soil has been collected.

 

Procedure:

 

1.    Put on a pair of latex gloves if what you are going to do requires extensive, direct handling of your sample (if available).

 

2.    Select a sample (soil or plant material).

 

3.    Prepare the sample for drying.

·        If the sample is soil:  obtain a quantity that is representative of all material in the original sample bag.

·        If the sample is a plant:  The plant must be washed to remove ALL soil.  After the soil has been removed, select portions of all parts of the plant (i.e. root, stem, branches, leaves, petals, flowers, etc…).  Select an equal amount of each.  Process enough material to completely fill your Petri dish.

 

4.    Obtain a Petri dish.  Use rubbing alcohol and a paper towel to remove any previous marks from your dish.  Label the bottom of the Petri dish using a Sharpie with your group number and the sample number (in red on the plastic bag).

 

5.    Obtain the mass of the Petri dish.  Record this number.

 

6.    Obtain the “wet” mass of your sample.  Record this number.

 

7.    Place the sample on a cart to go into a drying oven.

 

8.  Continue processing samples until the group has completed 4 total samples (2 plant, 2 soil).

 

9.  Consider the steps you went through in this procedure.  Spend the last 10 minutes of class placing in your journal/notebook those things you did today that would be applicable to your actual project in the field.  Recall any comments made by your teacher during the process.