1. What are the four types of evidence in a criminal investigation?
The four types are as follows-
Physical Evidence- tangible objects such as weapons, hair, blood, fibers, and fingerprints
Documentary Evidence- written or recorded evidence
Demonstrative Evidence- Helps illustrate or recreate a crime scene
Testimony Evidence- evidence given by a witness during trial
2. What are individual characteristics? Give an example of an individual characteristic?
Individual characteristics are when you can narrow the search down to a specific person. Such as you find a shoe print at the scene but this particular shoe is made custom for Dylan Inman then you know specifically who it is because of these individual characteristics.
3. What is the difference between individual characteristics and class characteristics?
The difference between individual characteristics and class characteristics is that individual characteristics will narrow it down to one person while class characteristics will narrow it to a group.
4. What are physical and chemical properties? Give an example of each.
Physical properties is when you refer to only that one object without comparing it to anything else an example may be that your describe the weight, size, color, and volume. While chemical properties is when a substance reacts with another substance. An example would be when baking powder and vinegar mix the chemical reaction is the swelling of the mixture.
5. What do forensic scientists do to collect and preserve soil samples?
To collect and preserve soil forensic scientists must not tamper with the soil in any way to preserve its original state. For example if some soil is caught in a tires treed the tire will be removed from the vehicle and it will be transported to the lab with extreme precautions.
Critical Thinking Questions
1. Why do you think forensic scientists are so careful that the tests they do are sensitive, reproducible, and specific? What might happen if they were less careful about this?
The reason forensic scientists put so much effort into testing evidence so carefully is because they want to make sure they get the same answer every time. If the scientists were not as careful as they are currently they may possibly contaminate the evidence which could ruin an entire case.
2. Which type of evidence do you think is most useful in an investigation? Why?
The most useful evidence is a testimony because if someone saw exactly what had happened then it goes way further than what a forensic scientist can do. I believe that because a in all my classes in school I learned an observation is better than an inference. An inference can be manipulated or not accurate but what you see is always true because it happened.
3. Why do you think that forensic scientists continue to look for class characteristics given their limitations?