Murder Lab

Who did it?

A forensics lab

Yesterday at 3 AM, at Mike's Awesome Bakery in Francestown, NH the baker arrived to find his assistant baker dead: lying in a pool of blood.  The victim's body was covered in a white powder.  

In an attempt to find the source of the white powder, investigators collect multiple samples from the bakery (baking soda, flour, baking powder, powdered milk, cornstarch).

Investigators are in the process of interviewing employees of the bakery to narrow their field of suspects.  They are also gathering clothing samples from employees to find a match for the white powder.

The investigators need your help.  They need you to write a lab procedure to help them identify the powder covering the body.

MATERIALS AT YOUR DISPOSAL

- baking soda

- baking powder

- flour

- cornstarch

- vinegar

- iodine solution

- universal indicator

- water

- lab materials (beakers, stirrers, pipettes, etc.)

-safety goggles

Objective: To find out which white powder was covering the body

Procedure: detailed step by step:

1. Put on safety goggles
2. Gather small amounts of each powder and liquid
3. Pour each powder into it’s column on the grid
4. Add a few drops of water to the first pile
5. Record the results
6. Add water to the rest of the powder in the row labeled water
7. Record results for each powder
8. Repeat steps 1-5 for each liquid
9. Take pictures and record results
10. Rinse grid

Analysis: (data)

Test Solutions	Baking Soda	Baking Powder	Flour	Cornstarch	Unknown
Water	Water stayed on top. Physical Change	Fizzy. Chemical Change	Nothing. Physical Change	Hard Goo. Physical Change	Fizzy. Chemical Change
Vinegar	Fizzed. Chemical Change	Lightly Fizzed. Chemical Change	Nothing. Physical Change	Absorbed Vinegar. Physical Change	Lightly Fizzed. Chemical Change
Iodine	Nothing. Physical Change	Turned purple and fizzed. Chemical Change	Repelled and turned grayish purple. Chemical Change	Turned Purple. Chemical Change	Turned purple and fizzed. Chemical Change
Indicator	Fizzed and turned green Chemical Change	Fizzed and turned orange/red/yellow Chemical change	Turned red Physical Change	Turned red Physical Change	Fizzed and turned orange/red/yellow Chemical change

Conclusion:

What powder should the investigators be looking for when they examine the suspects clothing.  How do you know?  How confident are you in your results and why?

The investigators should be looking for Baking Powder when they examine the suspects clothing. We know this because did a lab to see how certain powders (baking soda, baking powder, flour, cornstarch, and the unknown powder) reacted with other liquids (water, vinegar, iodine, and universal indicator). After the lab we concluded that the unknown powder is indeed baking powder. We are confident because none of the other powders reacted the same to the liquids like the baking powder and unknown powder did.