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Chapter 2 Data Analysis

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**What’s wrong with this sign?**

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Temperature 30°C 30°F

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**Système Internationale d’ Unités**

SI unit

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**Prefixes used with SI units**

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**English vs. Metric Units**

Which is longer? A. 1 mile or 1 kilometer B. 1 yard or 1 meter C. 1 inch or 1 centimeter 1.6 kilometers 1 mile 1 yard = meters 1 inch = 2.54 centimeters Left Image: Right Image:

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**m km mm cm Metric Units of Length**

The basic unit of length in the metric system in the meter and is represented by a lowercase m. Metric Units 1 Kilometer (km) = 1000 meters 1 Meter = 100 Centimeters (cm) 1 Meter = 1000 Millimeters (mm) Which is larger? A. 1 meter or 105 centimeters B. 4 kilometers or 4400 meters C. 12 centimeters or 102 millimeters D millimeters or 1 meter

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**1 centimeter = 10 millimeters**

Measuring Length How many millimeters are in 1 centimeter? 1 centimeter = 10 millimeters What is the length of the line in centimeters? _______cm What is the length of the line in millimeters? _______mm What is the length of the line to the nearest centimeter? ________cm

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**English vs. Metric Units**

1 pound = grams Which is larger? 1. 1 Pound or 100 Grams 2. 1 Kilogram or 1 Pound 3. 1 Ounce or 1000 Milligrams 1 kilogram = 2.2 pounds 1 ounce of gold = 28,349.5 milligrams

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**Kilogram Prototype Image - http://en.wikipedia.org/wiki/Kilogram**

Metric Units of mass kg mg g Mass refers to the amount of matter in an object. The base unit of mass in the metric system in the kilogram and is represented by kg. Metric Units 1 Kilogram (km) = 1000 Grams (g) 1 Gram (g) = 1000 Milligrams (mg) Which is larger? A. 1 kilogram or 1500 grams B milligrams or 1 gram C. 12 milligrams or 12 kilograms D. 4 kilograms or 4500 grams Kilogram Prototype Image -

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**English vs. Metric Units**

Which is larger? A. 1 liter or 1 gallon B. 1 liter or 1 quart C. 1 milliliter or 1 fluid ounce 1 fl oz = ml 1 12-oz can of soda would equal approximately 355 ml. 1 gallon = 3.79 liters It would take approximately 3 ¾ 1-liter bottles to equal a gallon. 1 quart = liters

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Metric Units kL cL mL L Volume is the amount of space an object takes up. The base unit of volume in the metric system in the liter and is represented by L or l. Metric Units 1 liter (L) = 1000 milliliters (mL) 1 milliliter (mL) = 1 cm3 (or cc) = 1 gram* Which is larger? A. 1 liter or 1500 milliliters B. 200 milliliters or 1.2 liters C. 12 cm3 or 1.2 milliliters*

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Measuring Volume We will be using graduated cylinders to find the volume of liquids and other objects. Read the measurement based on the bottom of the meniscus or curve. When using a real cylinder, make sure you are eye-level with the level of the water. What is the volume of water in the cylinder? _____mL What causes the meniscus? A concave meniscus occurs when the molecules of the liquid attract those of the container. The glass attracts the water on the sides.

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**Measuring Liquid Volume**

What is the volume of water in each cylinder? Images created at A B C Pay attention to the scales for each cylinder.

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**Measuring Solid Volume**

10 cm 9 cm 8 cm We can measure the volume of regular object using the formula length x width x height. _____ X _____ X _____ = _____ We can measure the volume of irregular object using water displacement. Amount of H2O with object = ______ About of H2O without object = ______ Difference = Volume = ______

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**Temperature Scales How hot? How cold?**

direction of Heat Transfer Celsius – C Freezing Point of Water 100 0C Boiling Point of Water Kelvin = C° + 273 No degree signs are used O Kelvin = C coldest possible temperature

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**What is the metric unit for…?**

Length – size meter (m) Mass – amount of matter Kilogram (kg) or gram (g) Volume – space something takes up Liter (l) or centimeters cubed (cm3) Temperature – amount of heat Kelvin (K) = celsius + 273

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**Density Measure of how much matter is squeezed into a given space**

density = mass volume

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Which one is more dense? A block of wood and a block of steel have the same volume

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What do you think? What happens to the density of an object if it is cut into pieces? Which has the greater density, a single uranium atom or Earth?

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**Scientific Notation coefficient x 10 raised to a power**

Single gram of hydrogen 602,000,000,000,000,000,000,000 molecules = 6.02 x 1023 molecules Mass of an atom of gold grams = 3.27 x grams

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Practice 36,000 3.6 x 104 503,000,000 5.03 x 108 7.6 x 10-4

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**The valid digits of a number **

Significant Figures The valid digits of a number In measurement: includes all of the digits that are known, plus a last digit that is estimated

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**Significant Figures Significant: Not significant nonzero digits**

final zeros after the decimal points zeros between two other significant digits Not significant zeros used solely for spacing the decimal point are not significant.

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**Examples each have only two sig figs 7.1 x 10-3 meter 4.2 x 10-1 meter**

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**# of significant figures**

Value 5.60 5.6 0.012 0.0120 0.0012 # of significant figures 3 2 5

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Rounding If the digit immediately to the right of the last significant digit is less than 5, it is dropped 5 or greater - last significant digit increased by 1 41.58 square meters 41.6 square meters

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**Practice Round 65.145 meters to 4 sig figs Round 100.1°C to 1 sig fig**

Round 154 cm to 2 sig figs 150 Round kilograms to 2 sig figs

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**Measurements with an Unlimited Number of Significant Digits**

Counting Example: 23 people in the classroom (Not 22.9 or 23.1) ………………. Exactly defined quantities Example: 60 minutes = 1 hour ……………………..

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**Calculation Rules calculated answer cannot be too precise**

not more precise than the least precise measurement Multiplication and Division same number of sig figs as the measurement with the least number of sig figs Addition and Subtraction same number of decimal places as the measurement with the least number of decimal places

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**Accuracy and Precision**

How close a measurement comes to the actual value of what is being measured Precision How close a series of measurements are to one another

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**Error Difference between accepted value and experimental value**

error = experimental value – accepted value % error = x 100% error accepted value

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**Error % error = x 100% 99.1°C – 100.0°C x 100% 100.0°C 0.9°C x 100%**

0.9% error accepted value = = =

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