MEASUREMENT

Scientific Notation Science often involves working with very large or very small numbers. Ex. Speed of light = 300,000,000 m/s Speed of snail = m/s Scientific notation makes very large or very small numbers easier to work with.

Scientific Notation Scientific notation = a way of expressing a value as the product of a number between 1 and 10 and a power of ,000,000 m/s number between 1 and 10 power of x10 8 The exponent (8) tells you that the decimal is 8 places to the RIGHT.

Scientific Notation For numbers less than 1, the exponent is NEGATIVE m/s The negative exponent tells you how many decimal places there are to the LEFT of x10 -4

Practice Write 9.8 x 10 8 in standard notation. Write 7.5 x in standard notation

Practice Write 6,500,000 in scientific notation. 6.5 x 10 6 Write in scientific notation. 5.6 x 10 -6

Multiplying Multiplying numbers in scientific notation – Multiply the numbers that appear before the multiplication signs – Add the exponents (3.0 x 10 8 ) x (5.0 x 10 2 ) = 15 x = 1.5 x 10 11

Dividing Dividing numbers in scientific notation – Divide the numbers that appear before the multiplication signs – Subtract the exponents 1.5 x = 0.50 x 10 3 = 5.0 x x 10 8

SI Units SI Units = International System of Units Using SI as the standard system of measurement allows scientists to compare data and communicate with each other about their results.

SI Base Units

SI Derived Units Kilogram kg Temperature kelvin K Time Second s

Metric Prefixes lsua.info

Limits of Measurement Precision = how exact a measurement is Which of the clocks is more precise?

Significant Figures Significant Figures = all the digits that are known in a measurement, plus the last digit that is estimated. The fewer the significant figures, the less precise the measurement.

How long does it take you to eat breakfast? 5 minutes 5 minutes, 15 seconds 5.25 minutes 1 sig fig 3 sig figs The digital clock is more PRECISE

Accuracy Accuracy = the closeness of a measurement to the actual value of what is being measured. If clock is 15 minutes slow, it may be precise but it is NOT ACCURATE.

Temperature Common Temperatures Fahrenheit (°F)Celsius (°C)kelvin (K) Water boils Human body Average room Water freezes kelvin refers to the lowest possible temperature that can be reached. This would be -273 °C, -459°F.

Significant Figures Rules 1.All NONZERO digits are significant g = 4 sig figs 1.2 g = 2 sig figs 2. Zeros between nonzero digits are significant 1002 kg = 4 sig figs 3.07 mL = 3 sig figs

Significant Figures Rules 3.Zeros to the LEFT of the first nonzero digit are NOT significant- placeholder g = 1 sig fig = 2 sig figs 4. Trailing zeros to the right of the decimal in a number are significant mL = 3 sig figs 0.20 g = 2 sig figs

Significant Figures Rules 5.Zeros at the end of a number (not to the right of a decimal) are not necessarily significant 190 miles = 2 or 3 sig figs 50,600 cal = 3,4, or 5 sig figs

When in doubt, convert the number to scientific notation. 506,000 = 5.06 x 10 5 = 3 sig figs

Quiz! Take out a half sheet of paper. (Tear one in half and share with your neighbor) Put your name on the paper. Label 1-5

Question #1 Why do scientists use scientific notation?

Question #2 Convert the following number to scientific notation:

Question #3 Solve this problem. (8.0 x 10 5 )/(4.0 x 10 3 ) =

Question #4 What is the SI Unit for mass?

Question #5 Is this an example of precision or accuracy?