Forensics

A forensic scientist may discover powder at a crime scene. In order to determine if it is illegal or not the crime lab will identify the substance using chemistry. Take on the role of a forensic chemist to identify unknown substances.

Become a Forensic Chemist by following these procedures and filling in the Powder Analysis Chart with your results. 

Complete the appearance, texture, and smell activities before opening the vinegar and iodine bottles.

Record your findings in the Powder Analysis Chart below.

Aim: To determine how different powders feel, look and react to other substances.

Hypothesis: 

Equipment: Baking Soda ,Cornflour, Sugar, Salt, Iodine, Magnifying, glass
Eye drop
Black card
Tea spoon / stick


Method: 

1. Place one-fourth teaspoon (1 ml) of the four white powders on a sheet of black construction paper. Label the powders with your pen.
2. Study the powders with the magnifying glass. Examine what each powder looks like. How would you describe the powder's shape. Does it have large or small grains? Your observations should be written in the appearance column of the chart.
3. Examine the powders further by rubbing each powder between your fingers. Describe how each powder feels in the Texture column of the chart.
4. Determine if there is a smell to any of the powders. Record your findings in the Smell column of the chart.
5. Take the eyedropper and place a drop of water on each individual powder. Examine what happens? Do the powders dissolve? Is there a reaction? Write your observations in the Reaction to Water column.
6. Place one-half teaspoon (2ml) of each powder in a separate jar. Add 2 drops of iodine to each jar using the eyedropper. Record what happens in the Reaction to Iodine column. Iodine should be handled with care.

Findings:  

Powder Analysis Chart

                                                                                                  
Substance          Appearance   Texture    Smell       Water                       Iodine
 
Cornflour                  smallest            soft     no smell    makes invisible barrier      bounces off it/ joins up.                                     

Sugar                      biggest              hard    no smell    absorbs                        absorbed it

Salt                        median       in between   no smell    absorbs                      changes colour

Baking soda             small                soft     no smell     barrier                        makes a barrier.

Comparing test results of substances that are known help Forensic Scientists identify unknown substances.

Summary: