1. Chapter 2 Review

2. Scientific Method
It is a 5 step process that outlines how to perform a proper experiment
The steps are
Observing and collecting Data
Formulating a hypothesis
Testing the Hypotheses
Theorizing
Publish results

3. Model vs. Theory Model Theory
A model is an explanation of how a phenomena occur and how data or events are related
A model can be any number of things visual, verbal or mathematical
Theory
A broad generalization that explains a body of facts or phenomena
Theories can be composed of multiple models such as the atomic model is part of the atomics theory

4. Measurement
Measurement represents a quantity or something that has magnitude, size, or amount
The globally accepted scientific measurement is SI measurement

5. SI measurement Part 1
The SI measurement system is composed of seven base units

6. Si units Part 2
Si units can also have prefixes that make the unit either a larger or smaller number without having to write all of the zeros

7. Practice with Prefixes
Kilometer
Centimeter
Decameter
Millimeter
1,000 Meters
100 Meters
10 meters
1,000 meters

8. SI units Part 3
Units can be combined such as to find density you need to divide mass by volume
These new units are called derived units

9. Practice with Derived Units
If a box is, 1 meter tall, 2 meters wide, and 3 meters deep then what is its volume
If the mass of an object is, 4 kilograms and a volume of 2 meters cubed then how dense is it
6 meters cubed
2 kilograms per meter cubed

10. Mass vs. Weight
Weight is a measurement of the gravitational pull on an object usually by using springs
Mass is a measurement done by using instruments like a balance

11. Accuracy and Precision
Accuracy: the closeness of measurements to the correct value of the quantity
Precision: the closeness of a set of measurements
Which of the following are accurate? Which are precise?

12. Percentage Error
The accuracy of a value can be compared with the correct value with the following equation:

13. Significant Figures
Rules: •Zeros between nonzero digits are significant. •Zeros in front of nonzero digits are not significant. •Zeros at the end of a number and to the right of a decimal point are significant. •Zeros at the end of a number to the left of a decimal point is not significant, unless there is a decimal point after the number.

14. Significant Figures, cont.
How many significant figures are in each of the following?
150.
3000
75.006
.098 3 1 8 2

15. Proportions Direct proportions Inverse Proportions
if two quantities are directly proportional to each other then dividing one by another gives a constant value
X/Y = K or Y=KX in which K is the constant
This means that if X increases then Y must increase proportionally to keep K a constant
Inverse Proportions
Two quantities are inversely proportional to each other if their product is constant
XY=K in which K is the constant
This means that if X increases then Y must decrease proportionally to keep K a constant