Testing for ions.

• Seawater – Na+, K+, Ca2+, Cl-, So42-, Co32-
• Lake water – Ca2+, Cu-, Cl- 

• Bath water – Na+, Co32-

Safety points.

There were a few safety points that we had to be careful with so that the experiment would go right and that no one would get hurt.

1. Making sure that we wore goggles when doing the experiments.
2. Working with reactive chemicals.
3. Making sure that we don’t get the chemicals onto us.
4. Making sure that when we were using the wire loop we had to clean it after every use just in case the chemical left on the wire would not react with other chemicals when used.
5. Making sure that you don’t burn your hands when testing the chemicals underneath the Bunsen burner.
6. Making sure that you don’t spill the chemicals onto the floor or on others.
7. Making sure that you tidy up the equipment so that no one can get hurt

 

Materials and method used.

Materials used.

The equipment that we used for the experiment were –

Wire loop

Bunsen burner

Glass tubes

Chemicals

Method.

We had to do 2 separate test for the specific types of chemicals we did 2 different test so that we can get better results.

Testing with solutions.

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

 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.

These are the results we got after each chemical we tested.

Conclusion.

I think that the test was successful because we were able to confirm that the person died in the seawater. We found out the  ions that was in the person’s lungs matched the seawater and not the other substances.

Evaluation.

I think that our tests was successful because we tested the different types of water to find out that in the end we was able to tell what was the woman’s cause of death.

Strength's and Weaknesses.

Modifications.

There are a few modifications that would have made the experiment even more successful like –

• Using an un-reactive wire loop like a platinum loop, which is un-reactive at all, which would have given better results to the experiment.
• We could have done the experiment a couple of times, which would have also given us better results to the experiment.

Discussion of vocational Implications.

A forensic scientists would carry out the tests in the same way as we did in school but they would use more reliable equipment for the tests for example they would use a mass spectrometry which is used to get readings of a sample that is put into the machine. When a sample is put into the machine by a scientist the machine would do tests to find out what they would know what they would be looking for after the test is complete the machine would give out a reading on paper showing what ions where present in the sample.