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Forensic Science Investigation/Lesson: Difference between revisions
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Forensic Science Investigation/Lesson (view source)
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, 13 years ago→Chromatography to study the ink in the pen
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Here are fingerprints from two suspects. Look carefully at them and label the patterns using the clue sheet as a guide. | Here are fingerprints from two suspects. Look carefully at them and label the patterns using the clue sheet as a guide. | ||
[[Image:Fingerprints2_SC004.png|Fingerprints2_SC004.png|900x700px]] | |||
== Clue Sheet == | == Clue Sheet == | ||
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3. Dip a small piece of yellow indicator paper into the muddy water and allow the water to soak up the paper. <br /> | 3. Dip a small piece of yellow indicator paper into the muddy water and allow the water to soak up the paper. <br /> | ||
4. Match the colour with the | 4. Match the colour with a colour chart.<br /> | ||
Acids turn the paper red, alkalis turn the paper dark blue, neutral soils turn the paper green.<br /> | |||
== Soil Washing Clues == | == Soil Washing Clues == | ||
Samples of soil were collected from a suspect’s shoes and from the footprint outside the broken window. Test these samples and stick your indicator paper | Samples of soil were collected from a suspect’s shoes and from the footprint outside the broken window. Test these samples and stick your indicator paper on a sheet of divided into three columns (Suspect A, Suspect B and Suspect C). Then write down what you think these clues tell you. | ||
Suspect A Suspect B Suspect C | |||
== Chromatography to study the ink in the pen == | == Chromatography to study the ink in the pen == | ||
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3. Watch the water rise up the paper carrying the dye particles with it.<br /> | 3. Watch the water rise up the paper carrying the dye particles with it.<br /> | ||
4. Be patient and let the water run almost to the top of the paper.<br /> | 4. Be patient and let the water run almost to the top of the paper.<br /> | ||
5. You will be able to see the different colours of ink along the strip of paper. | 5. You will be able to see the different colours of ink along the strip of paper. | ||
== Clues from the pen == | == Clues from the pen == | ||
You have samples of ink from the pen found at the scene of the crime and ink from cartridges found in the pocket of the two suspects. Test them and see if you can link the suspect to the crime. Stick your strips of paper, called chromatograms, | You have samples of ink from the pen found at the scene of the crime and ink from cartridges found in the pocket of the two suspects. Test them and see if you can link the suspect to the crime. Stick your strips of paper, called chromatograms on a sheet of paper divided into three columns (Suspect A, Suspect B and Crime Scene). Write down what you think these clues tell you. Can you advise the police on who the murderer might be? Look at the evidence you have collected. Summarise your ideas. | ||
== Acids and Alkalis are in your home== | |||
Acids and Alkalis are in your home | |||
Acids turn indicator red. Alkalis are the opposite of acids and turn indicators blue. Find out which kitchen chemicals are acids and which are alkalis. This is what you need to do:<br /> | Acids turn indicator red. Alkalis are the opposite of acids and turn indicators blue. Find out which kitchen chemicals are acids and which are alkalis. This is what you need to do:<br /> | ||
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1. First add one drop of green indicator to each well of a white tile.<br /> | 1. First add one drop of green indicator to each well of a white tile.<br /> | ||
2. Now add one drop of each test liquid to the correct well. For example, add liquid number one to well number one. Always use a clean pipette for each new liquid.<br /> | 2. Now add one drop of each test liquid to the correct well. For example, add liquid number one to well number one. Always use a clean pipette for each new liquid.<br /> | ||
3. Write down what colour the indicator turns when the liquid is added in | 3. Write down what colour the indicator turns when the liquid is added in a table.<br /> | ||
My mum uses vinegar on both wasp stings and bee stings. Is she right? | My mum uses vinegar on both wasp stings and bee stings. Is she right? | ||
Test the bee stings and wasp stings and suggest what she could use from the kitchen for each sting. | Test the bee stings and wasp stings and suggest what she could use from the kitchen for each sting. | ||
