International System of Units: SI System Universally accepted way to make measurements. Based off of the number 10 Conversions can be done easily

Length Distance between two points. The Base SI unit of measurement for length is a meter (m). How do you measure length?

Mass A measure of the amount of matter in an object. SI unit of measurement: gram (g) Mass remains constant no matter where an object is in the universe. Measured with a triple beam balance.

Other Important Measurements MeasurementUnit (symbol) Temperature – Average kinetic energy of particles in a substance Kelvin (K) TimeSecond (s)

Volume Derived measurement from length. The amount of space an object takes up. SI units – m 3 (meters cubed) Liquid volume can be measured in a graduated cylinder – Liters (L) 1 cm 3 = 1 mL

Other Derived Measurements MeasurementUnit (symbol) AreaMeters squared (m 2 ) DensityGrams per centimeter cubed (g/cm 3 ) PressurePascal (kg/m∙s 2 ) (Pa) EnergyJoule (kg∙m 2 /s 2 ) (J)

Metric Conversions Would we measure the distance from Storrs to Hartford in meters? 1 kilometer (km)= 1000 meters.

SI Prefixes kilo k thousand (10 3 ) 1,000 Hecto h hundred (10 2 ) Deca d Ten (10) deci dc tenth (10 -1 ).1 centi c hundreth (10 -2 ).01 mili m thousandth (10 -3 ).001 micro μ millionth (10 -6 ) nano n billionth (10 -9 )

Ladder Method for Metric Conversions

Practice problems 1. 2,564 kg = ______mg L= _____ kL 3. 4,789.6 g = _______mg 4. 1, mm = _____m

Scientific Notation Definition: A way of expressing a value as the product of a number between 1 and 10 and a power of 10. For example, the number 1,000,000,000 can be written in scientific notation as 1.0 x In other words, the exponent, 9, tells you that the decimal point is 9 places to the right of the 1. What is the value of a number that has the scientific notation of 7.6 x ?

Why Scientific Notation? How far do you think the earth is from the sun? What is the mass of an electron? (Negatively charged particle that moves around an atom) Big or Small, Scientific Notation Fixes it all!

Astronomical Unit Distance from the Earth to the sun 149,597,870,700 m

Mass of an electron grams

Scientific Notation Makes it easier AU = 1.49 x meters When we multiply a positive exponent, we move the decimal point to the right, that many place values. Mass of an electron= 9.1 x When we multiply by a negative exponent, we move the decimal point to the left, that many place values.

Multiplying Scientific Notation When you multiply, you multiply the coefficients and add the exponents. When you divide scientific notation you divide the coefficients and subtract the exponents. Needs to be between 1 and 10

Multiplying (1.6 x 10 7 ) x (2.1 x 10 6 ) (2.76 x 10 8 ) x (3.6 x 10 4 ) Division (7.2 x 10 6 ) / (8.4 x 10 4 ) (5.2 x ) / (7.2 x )

Accuracy vs. Precision of Measurement Low Accuracy High Precision High Accuracy Low Precision High Accuracy High Precision Accuracy: How close measurement is to the TRUE value. Precision: How close your measurements are to each other.

Significant Digits Measurement is only as accurate as the tool that makes the measurement. Significant digits shows level of accuracy in measurement. Significant digits can be applied to coefficients in scientific notation. Accurate to 0.01 gramsAccurate to 0.1 grams

Significant Digit Rules – Whole Numbers All non zeros are significant (4,223 has 4 sig. digits) Any zeros in between significant digits are significant. (4,003 has 4 sig. digits) Any zeros to the left of the decimal are not significant (4,000 has only 1 sig. digit) Zeros to the right of a decimal not followed by non-zeros are significant ( has 5 sig. digits).

Significant Digit Rules - Decimals Zeros to the right of a decimal are not significant if they come before non zero digits. (0.035 has 2 sig. digits) Zeros following the decimal after non- zero digits are significant ( has 3 sig. digits)

Significant Digits and Math Operations Addition and subtraction: Final Answer is only accurate to the number with the least number of decimal places. Ex: = has one decimal place, so we round to Multiplication and Division: Final answer can only have the same number of significant digits as the number with the least number of significant digits × × 5 = has only one significant digit, so we round to 20

How many Significant Digits? Questions Answers 1. 1, , , ,555,