If you could point out the differences, props to you. If you couldn't point them out or if you sensed something different but you couldn't put your finger on it, then don't worry because you're a part of the majority of people who couldn't! (Sorry, not all of us are special).

What this video proves is the unreliability of eyewitness testimonies in court and in life. We overestimate the accuracy of eyewitness testimonies, often disregarding  the factors which influence a witness's ability to accurately identify a suspect, including how much stress a witness is under, whether a weapon is present, the amount of time a witness had to look at the person, the lighting present at the time, how long it's been since someone first witnessed the crime or suggestions of guilt by police, etc. This point, fortunately, has been brought to the attention of the court and now measures are being taken to prevent false accusations based solely on eyewitness testimonies. Thankfully, we have Forensics Biology to help us identify the true verdict through hard evidence. This is exactly what we covered in Jerrel's missing iPod case. 

While attempting to pin point the iPod thief, we attempted to investigate what exactly were the substances this criminal left on the crime scene (careless, rookie mistake). However, before attempting to see what substances made up this compound, we first had to figure out how to identify whether or not a substance contained protein, glucose, lipids or carbohydrates.

(Left to right): Lipid, Water, Protein, Glucose, Starch

• You can test whether or not a substance has Glucose present by mixing 10 drops of Benedict Reagent with it and then heat it in a water bath. The colour will change to a fiery orange if it does (see right) Alternatively, you could use a Glucose Strip. 
• You can test whether or not a substance has Starch present by dripping 3 drops of Iodine into a sample of the substance. The colour will change to a dark blue colour if it has starch present. 
• You can test whether or not a substance has Protein present by dripping 10 drops of Biuret into a sample of the substance. The colour will turn from pale blue to a lavender purple.

  Iodine and Biuret Tests

• Finally, you can test a substance for Lipids by doing the Paper bag test. Lipids will leave a greasy, shiny stain on unglazed brown paper bags.
  
  

  Paper bag test (still in the process of drying)

After testing the sample of evidence for glucose, starch, protein or lipids, we came to the conclusion that Bruce was the criminal in this case because he ate Toast with butter and jelly for lunch, which corresponds to the crumbs that were left on the crime scene. The crumbs only had glucose present, which means that it had to be Bruce because no other employee had only glucose present in their lunch meal. Case closed.

Rachel Putri Utomo
Block F, Honors Biology
Mr. Kevin Quick
Academic Year 2013-2014