SAMPLES FOR ANALYSIS

What are my objectives while studying this topic?


By studying this topic you’ll learn about the different ways samples are taken. When you have done this, you will be able to report on how you have taken samples and tested them when you carry out your chromatography and colorimetry experiments.


Why is this important?


Have you seen ‘Waking the Dead’ on TV? If you haven’t, it’s a programme about how a team of forensic scientists try and solve crimes. They usually succeed! During the course of their investigation you see them taking several samples from a crime scene. These samples are then analysed.


Before you can analyse a sample, it needs to be first of all taken from a scene and then prepared for analysis. You will surely have seen something on TV that shows this processes, be it factional or fictional: blood samples, hair samples, samples of footprints and so on. You may have taken water or soil samples whilst working on a geography project, for example.


Can I get an introduction to this topic?


Yes, why not have a look at the following clip:



So, let’s get to it: what is analysis?


Analysis is the process of breaking down chemical processes and examining chemical reactions between elements of matter. For example, analysis of the concentration of elements is important in managing a nuclear reactor, so nuclear scientists will analyse neutron activation to develop discrete measurements within vast samples. For this reason, analysis is an important element of national security among the major world powers.


What will I be expected to be able to do after studying this topic?


  • Know how to take a sample for analysis using a relevant sampling technique

  • Prepare a sample for analysis


What are the key words to learn and use?


  • Soluble

  • Forensic

  • Insoluble


How long will this topic take to study?


On average you’ll be looking at about three hours of study time.


What are the main activities on this topic?


Investigate!


Work in small groups and investigate how different samples of obtained and then prepared for analysis. Samples looked at should be: blood, paint, soil, fibres, tyre tracks, bite marks, water and urine. Each group then reports to the rest of the class on their findings for the samples. Reporting on the samples should be split between the groups in order to avoid repetition.


Some information on the more bizarre samples can be found at the following site:



Experiment!


Investigate different soil samples for pH, water-holding capacity, sedimentation test.


Ideas for implementation can be found below:



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