Testing for ions

Materials and Methods

       

  In the experiment there were two different experiments these were testing with solutions and flame test.

Materials

1. Test tube
2. Solutions
3. Goggles
4. Test tube rack

Testing with solutions

1. Pour approx 3cm depth of control solution into a test tube.
2. Add a few drops of the specified test solution.
3. Make a note of any colour changes or precipitates formed.
4. If a gas is produced, bubble the gas through limewater.

Materials

1. Wire loop
2. Hydrolic acid
3.  Bunsen burner
4. Solution or Substance
5. Goggles

Flame test

1. Clean a wire loop in a roaring Bunsen flame.

      2. Rinse the wire loop in hydrochloric acid.

3. Dip the wire loop into the test solution or substance.

4. Test the solution by placing the loop back in the roaring Bunsen flame.

5. Make a note of any colour change in the flame.

Results

 

Conclusion

The water that was taken out of the lungs of the women contained three ions these were Co3 2-, Cl- and Na+. When we tested the lake water it did not have Na+ in it which was in the lung water. Also we tested a second ion which was Cl- this was in the lake and also in the lung water. The last ion that we tested was Cu2- this was in the lake water but was not in the lungs which made it clear that she had not been drowned in the lake water the lake water also had one more ion than the lung water which made it 100% correct.

We also tested sea water because the body was found in the sea. The sea water had Na+ in it the lung water also contained Na+. Then we tested for Cu 2- which was not in the sea water and was not in the lung water. The sea water did not have Cl- and Co3 2- which was in the lung water this showed that the body was drowned in the sea water.

The last water we tested was bath water the first ion we tested for was Na+ this was in the bath water and also in the lung water. The second ion we tested was Cl- this was not in the bath water but was in the lung water. The third ion we tested was Co3 2- this was in the bath water and was also in the lung water. The last ion we tested was Cu 2- which was not in the lung water and was also not in the bath water. This shows that the most likely thing that happened was the women got drowned in the bath and then here body got dumped in to the sea.

Evaluation

I think the test were reliability but not very reliable because in one of my test it showed that one of the ions was in the lung water but was not in the bath water but I still think that I got the experiment right the reason being that it still showed the other ions which did not show up in the lake water and sea water. Also another problem that I encountered was when I was doing the test some of the colour test where not very easy to tell so I found it hard.

The equipment errors that I encountered were the three waters they were made by the school and they used tap water instead of distilled water. This gave some of result to be wrong the reason being the tap water has a lot of different ions in it so I may have got some wrong results. Another equipment error that I encountered was the wire loop was made from a different metal and was not platinum; platinum is what forensic scientist use in the flame test so this could have affected my results.

The human errors that I could have had are first of all I could have not been following the procedure properly and do the wrong thing in the experiment which would change my results that I get. Another human error that I could have had is when I was doing the flame test I may have not put enough substance on the wire loop which would give a different colour that would change the result in the test.

I did not have any design errors and did not find any.

Discussion of vocational implications

A forensic scientist would carry out the test in a different manner. He/She would do it in a laboratory and would a protective suit and gloves so they do not contaminate the sample or catch any dieses from the sample. They also would use more sophisticated equipments like we used a different metal wire rod to the platinum that they would use in the laboratory. This would give forensic scientist more better results than the ones that we got.