Chapter 9: Glass Examination Flashcards
The Todd Christensen was solved through what type of analysis?
Glass and plastic analysis
How did they solve the Todd Christensen case?
- They received a tip from a citizen who knew the culprit and who thought he was the suspect based on the car he drove
- They looked into John (suspect) who denied that it was him in the hit and run
- They gained access to his garage and found a broken piece of orange plastic on his work bench
- This plastic casing of a turn signal matched up to the pieces found at the scene of the crime
What comparative analysis did they do to solve the Todd Christensen case?
- Paint chips and plastic signal chips from scene of crime compared to the ones found in his garage on the workbench
What is a physical property?
Physical properties describe a substance without reference to any other substance.
What are examples of physical properties?
- Weight
- Volume
- Colour
- Boiling point
- Melting point
What is a chemical property?
A chemical property describes the behavior of a substance when it reacts or combines with another substance.
What is matter?
Matter is anything that has a mass and occupies space.
What is an element?
An element is the simplest substance known and provides the building block from which all matter is composed.
What is a compound? (in chemistry)
When elements combine
Give an example of a compound
- NaCl
- NaOH
- KOH
- H2O
- CO2
etc
What is an atom?
- An atom is the basic particle of an element
What is a molecule?
- molecule is the smallest unit of a compound.
- a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.
What are the 3 states of matter?
- Solid
- Liquid
- Gas
Define a solid.
Definite shape and volume
Define a liquid.
Specific volume, takes the shape of its container
Define a gas.
Neither a definite shape nor volume
What system of measurement do scientists throughout the world use?
Metric system
What are the basic units of measurement for length, mass, and volume in the metric system?
- Meter
- Gram
- Liter
What are common prefixes used in the metric system?
- Deci
- Centi
- Milli
- Micro
- Nano
- Kilo
- Mega.
What is temperature? (Definition)
Temperature is a measure of heat intensity, or the hotness or coldness of a substance.
What is the most commonly used scale for temperature?
Celcius
What is the freezing and boiling point of water?
Freezing - 0°C
Boiling - 100°C