1. Physical Science Ch 2

2. Standard – Exact quantity that people agree to use for comparison Purpose - When all measurements are made with same standard, measurements can be compared Measurement system – English Metric- multiples of 10 International System of Units

3. Chapter 2
-Units of measurement and standards -Length -Mass -Time -Temperature -amount of a substance (atoms/molecules) -Electrical current -luminosity -3 types of graphs

4. Length
-The distance between two points SI Base Unit = meter SI is based in powers of ten: -deci- means 1/10 -centi- means 1/ cm = 10 dm = 1 m

5. Using Math How many centimeters are in 1.98 meters?
Problem-Solving Steps:
What is known? 1 m = 100 cm
When converting from larger units (m) to smaller (cm) you multiply

6. 1.98 m x (100 cm/1 m) = 198 cm

7. Volume
-The amount of space occupied by an object -If length, width, and height are expressed in centimeters, then volume (length x width x height) is expressed in: cm3 “cubic centimeters” -No tool can measure volume, so combine 2 SI Units (refer to p 38)…. -Volume units are derived units; - 1 Liter = 1 cubic decimeter (dm3)

8. Practice problem w/ Volume
How many liters of gasoline are in 538 cm3?
What is known
1 cm3 = 1 mL and 1 L = 1000 mL….therefore
1 L = 1000 cm3
When converting from smaller units (cm3) to bigger (dm3), you divide
538/1000 =?

9. Answer
538 / 1000 = L

10. Mass
A measurement of matter in an object SI unit is kilogram (kg). For objects of small mass, grams (g) or milligrams (mg) are used Convert from g to kg, etc.

11. Density
-Like volume, density is a derived unit -Mass per unit volume, or mass/volume (g/mL) -Each material has its own unique density

12. Temperature
The amount of thermal energy (heat) in a substance. **For now, think of temperature as “how hot or cold something is” -Temperature is measured on the Celsius (c) scale -Water at freezing = 0 degrees C; water at boiling = 100 degrees C -SI Unit is Kelvin (K) = NO DEGREE SIGN!!; find Kelvin by adding 273 to the Celsius temperature

13. homework
p. 56 # 1-10, DUE THURSDAY!

14. 2.3: Graphs
Line Graphs: ‘
-used to show trends or how data changes over time
What information is shown here?

15. Graphs
Bar Graphs:
Useful for comparing information collected by counting
Height corresponds to a number of (y)
This bar graph shows…?

16. Graphs
Circle Graphs
- How a fixed # is broken into parts (i.e. percentages)
The circular pie represents the total (i.e. 100 %)
What does this ex show?
Percent Energy Stored by Fuels

17. Importance of graphs A visual display of informationor data
Who uses graphs?
Businesses
Sports, sport agents, coaches
Economics
Politics
Engineering
Science and research
???Anyone else???

18. Homework
p. 56 # 13, 14, 22, 23

19. Slope: y = mx + b Two points, subtract y-y and x-x: m = (y1-y2)/(x1-x2)