1. 1.3: Measurement and Scientific Notation

2. Unit I Quiz Get a partner.
Get a whiteboard, piece of paper towel, and marker
Review your notes with your partner until the bell rings

3. SI Units of Measurement
A measurement must have a number and a unit in order to makes sense.
Units such as inches, feet, °F are not used in science
Scientists use a set of measuring units called SI, or the International System of Units.
Scientists can interpret one another’s measurements using SI.

4. Base and Derived Units
SI Units of Measurement: base units and derived units
SI is built upon seven metric units (base units)
Base unit: length (meter), mass (kg)

5. Base and Derived Units
SI Units of Measurement: base units and derived units
Derived units: units made from combinations of base units
Ex. Density (mass/volume)=kg/m3

6. Metric System SI Units of Measurement: Metric Prefixes
A metric prefix indicates how many times a unit should be multiplied or divided by 10.
Sometimes units have to be converted to other units (grams to kilograms)

7. Metric System
Conversion Factor: a ratio of equivalent measurements that is used to convert a quantity expressed in one unit to another unit
Example: 1 kilometer (km) = 1000 meters (m)
OR meters (m) = 1 kilometer (km)

8. 1.3: Metric Mania - Handout

9. Precision in Measurement
Precision: a gauge of how exact a measurement is
If a measurement has more significant figures, it is more precise.
Significant figures: all the digits that are known in a measurement, plus the last digit that is estimated.
Example: 2.5 = two significant figures (sig figs)
Example 2: = four significant figures (sig figs)

10. Precision in Measurement
The precision of a calculated answer is limited by the least precise measurement used in the calculation.
Example: 2.5 x = 7.89 = 7.9
2.5 is the least precise (contains two significant figures, while contains four significant figures)

11. Accuracy in Measurement
Accuracy: the closeness of a measurement to the actual value of what is being measured
Example: the actual time is 8:35 pm. A clock with 8:32 pm is more accurate than a clock with 8:30 pm.

12. Measuring Temperature
Temperature: a measure of how hot or how cold something is [base unit is Kelvin (K)]
Thermometer: device used to measure temperature
Two most familiar scales: Celsius and Fahrenheit (Fahrenheit is not used in science)
Water Boils at 100° C = 212° F
Water Freezes at 0° C = 32° F

13. Measuring Temperature
Temperature can be converted from Fahrenheit to Celsius to Kelvins.
° F = 1.8 (° C) + 32
° C = (° F ) / 1.8 – 32
° K = ° C
Note: Fahrenheit cannot be converted directly to Kelvins.
0 ° Kelvin: lowest possible temp that can be reached (absolute zero).
0 ° K = C

14. 1.3: Metric Worksheet - Handout

15. Measurement Lab

16. Scientific Notation
Scientific notation: a way of expressing a value as the product of a number between 1 and 10 and a power of 10
Used when working with very large or very small numbers.
Example: 6,000,000=6.0 x 106

17. Scientific Notation
6.0 x 106 (exponent indicates the decimal is really 6 places to the right of the 6)
For any number <1, the exponent is negative (exponent indicates the number of places to the left of the number that the decimal is)

18. Scientific Notation
Multiplication: multiply numbers in front of the multiplication sign and add the exponents together
Example: (3.0 x 103) x (2.0 x 105) = 6.0 x 108
Division: divide numbers in front and subtract the exponents
Example: (8.0 x 1012) / (2.0 x 106) = 4.0 x 106

19. Section 1.3: Using Scientific Notation

20. 1.3: Scientific Notation – Handout