Critical Thinking and Doppler Effect

Review Questions
1. What is the NIBIN? NIBIN stands for National Integrated Ballistic Information Network
2. What is rifling? What two types of markings does this produce? Rifling is the spiral grooves cut into the barrel of a gun. Two types of markings are grooves (low areas cut into the barrel) and lands (the raised areas between the grooves)
3. What is a distance determination? How is this done? The process of estimating the distance between where a shot is fired and its target. It is often done by looking at the patterns of powder residue and the shot pattern.
4. What is the Greiss Test? Uses chemicals to develop gunpowder residue patterns, particularly around bullet holes.
5. When a bullet is retrieved, how is it marked for identification purposes? What should be avoided? It is marked with the investigators initials. Covering up the mark so it won’t obscure any striations or markings on the bullet.
Critical Thinking Questions
1. If you found a firearm at a crime scene, what steps would you take in order to transport the weapon to the lab? I would wrap it up in tissue paper and place it in an envelope or pillbox.
2. Why do you think it might be useful to know the distance between a gun fired and its target? So that you know where the bullet may have landed.
3. If you were in charge or retrieving bullets at a crime scene, what steps you would you take to retrieve a bullet and take it to the crime lab?
4. What are some of the challenges in analyzing tool marks? Trying to find what tool was used to make the mark.
5. What is the Doppler Effect? How can the Doppler Effect be useful for a forensic investigation involving a shooting? Doppler Effect is the sound waves getting stretched behind a travelling object.