Let's use our Forensics Knowledge to solve a crime!

White powder test?

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: 
I thought that with the Iodine that the powders would burn, and simply with the water it would dissolve.Equipment:

Baking Soda
Cornflour
Sugar
Salt
Iodine
Vinegar
Magnifying glass
Eyedrop
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

B=Cornflour            Clean       Fine  Can't smell it.    Sits       Still sits, turns white. 

D=Sugar       Small-medium    Coarse  Sweet        Dissolves   Dissolves, turns yellow

C=Salt                   Small       Coarse   Strong       Dissolves    Dissolves, turns yellow

A=Baking soda       Clumpy    Soft  Can't smell it. Dissolves/sits  Sits, turns yellow.

     

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

Summary: 

When the water was put on the powders the cornflower test just sat there. The rest just dissolved.