1. Ch. 2 – Scientific Method
A systematic approach to solve problems through investigations by 1. Observing, 2. Generalizing, 3. Theorizing, 4. Testing, 5. Conclusion.
What’s done in an observation
Collect data, communicate
Generalizing
Organize data, hypothesis
Theorizing
Planning and predicting

2. Test
Design experiment, test, graph and interpret results
Conclusion
May change hypothesis and retest
Explain what happened in your results

3. Measurements Why do we need measurements?
If I told you to go get me a pop would you know what size?
The International System of Units (SI) is used throughout the world so we don’t confuse figures and measurements.
SI is metric
Written the following way: or
7 SI fundamental units  Mass, time, temperature, length, amount of substance. Pg. 34

4. SI Unit Prefixes Unit of measurements for length KHDMDCM
Kilo, hecto, deka, meter, deci, centi, milli
Ex. Kilogram (1000 grams) or Kilometer (1000 meters)
1 gram is about 1 pencil mass
Your book is about 2 Kg
Derived Unit – are combinations of fundament al units.

5. Derived Units Area  length X width (m2)
Volume  length X width X height (m3)
Volume is the amount of space occupied by an object.
1ml = 1cm3
1 liter = 1000-ml
1 ml = how many liters?
Density is mass divided by volume (D=m/v)
How heavy something is for its size.
Ex. Pg. 38 (Density Lab)

6. Temperature is the measure of the average kinetic energy of the particles in a sample of matter.
What is the SI unit for temp.?
Kelvin (K)
Heat is the sum of the kinetic energy of the particles in a sample of matter.
How does a thermometer work?
We use Celsius more than Kelvin
0 C = 273 K – freezing point
100 C = 373 K- boiling point

7. Joule is force times length (f X l)
1 J = 1 n-m
Joule is the SI unit for energy
A calorie is the amount of heat needed to raise the temperature of 1 g of water 1 degrees C.
1 calorie = J
Kcal or C = KJ
Food Calories are kilocalories.
Conversion Factors – Sample Problem 2-2

8. Specific heat is the amount of heat energy required to raise the temp
Specific heat is the amount of heat energy required to raise the temp. of 1 g of a substance 1 degree C.
Label is J/g x C
Water heats up and cools down slowly, thus it has a high specific heat.
Accuracy vs. Precision
Precision is determined by how close your results are to each other.
Accuracy is determined by how close your results are to the correct answer.
Ex. Dart Board

9. SIGNIFICANT FIGURES
Significant figures are all the digits known with certainty plus one final digit, which is uncertain or estimated.
Read pg. 46 – bottom 2 paragraphs
Read pg. 47 – Table 2-5
Do Sample Problems on pg. 47 & 48
Rounding off Addition & Subtraction Problems
Rounding off Multiplication & Division Problems

10. Scientific Notation
This is very helpful to determine the correct number of significant figures.
Ex  X 104
Ex  X 10-3
Ex  X 107
Using Adding & Subtracting Scientific Notation
Using Multiplying & Dividing Scientific Notation