9Lab Ch 1 Notes.pdf

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Physical Science

Chapter 1

Section 1

Measurments

Learning Goals

*Define measurement.

*Compare English and SI measurements. *Become familiar with metric prefixes.

* A

measurement

is a determination

of the amount of

something.

*A measurement

has two parts:

*a

number

value

and

*a

unit

Two Common Systems

*The English System is used for everyday measurements in the United States.

*Miles, yards, feet, inches, pounds, pints, quarts, gallons, cups, and teaspoons are all English system units.

*In 1960, the Metric System was revised and simplified, and a new name was adopted— International System of Units.

International System of

Measurement (SI)

*The acronym SI comes from the French name Le Système International d’Unités.

*SI units form a base-10 or decimal system. *In the metric system, there are:

*10 millimeters in a centimeter, *100 centimeters in a meter, and *1,000 meters in a kilometer.

Classwork

*1.1 Review page 8 #1 - 7

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Physical Science

Chapter 1

Section 2

Time and Distance

Learning Objectives

*Explain the meaning of time in a scientific sense.

*Discuss how distance is measured. *Use a metric ruler to measure distance.

*Two ways to think about time:

*What time is it? *How much time?

*A quantity of time is also called a time interval.

* Time comes in mixed units.

*Seconds are very short.

*For calculations, you may need to convert hours and minutes into seconds.

9045 seconds

Practicing converting units of time.

1. Convert 2 hours to minutes.

2. Convert 423 minutes to minutes and

hours.

3. Convert 23 minutes to seconds.

*Distance is the amount of space between two points.

*Distance is measured in units of length.

*The meter is a basic SI distance unit.

*Prefixes are added to the names of basic SI units such as meter, liter and gram.

*Prefixes describe very small or large measurements.

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* A meter stick is 1 meter long and is divided into millimeters and centimeters.

The meter stick

* Each centimeter is divided into ten smaller units, called millimeters.

The meter stick

What is the length in cm?

2.60cm

Classwork

*1.2 Section Review Page 12

*#1 - 8

Homework

*Read 1.3

Physical Science

Chapter 1

Section 3

Converting Measurements

Learning Objectives *Write conversion factors.

*Apply the decimal point rule to convert between metric quantities.

*Use dimensional analysis to convert English and SI measurements.

* To convert 1,565 pennies to the dollar amount, you divide 1,565 by 100 (since there are 100 pennies in a dollar).

* Converting SI units is just as easy as converting pennies to dollars.

Practice Problems: Moving the decimal Convert 655 mm to m

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Converting units

*A conversion factor

is a ratio that has the value of one.

*This method of converting units is called dimensional analysis.

*To do the conversion you multiply 4.5 feet by a conversion factor

Practice Problem: Using conversion factors Convert 4.5 ft to cm

1. Looking for:

2. Given:

3. Relationships:

4. Solution:

Conversion Practice!

More Practice!Use the correct conversion factor to convert: 175 yds. to m.

2.50 in. to mm.

Classwork

*Section Review Page 17

*#1 - 6

Homework

*Read 1.4

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1 inch = 2.54cm =

= =

= 1Km 0.62mi

1L 1.06quart

1Kg 2.2 pounds

1oz 28g

1. 7.0 km ≈__________ mi

1 inch = 2.54cm =

= =

= 1Km 0.62mi

1L 1.06quart

1Kg 2.2 pounds 1oz 28g

2. 115 g ≈ __________oz

1 inch = 2.54cm =

= = =

1Km 0.62mi 1L 1.06quart

1Kg 2.2 pounds

1oz 28g

3. 2 ,000. lb. _≈ __________kg

1 inch = 2.54cm =

= =

= 1Km 0.62mi

1L 1.06quart

1Kg 2.2 pounds

1oz 28g

4. A 2.0-liter bottle of soda is about how many quarts?

1 inch = 2.54cm =

= =

= 1Km 0.62mi

1L 1.06quart

1Kg 2.2 pounds

1oz 28g

5. A pumpkin weighs 5.4 pounds. What is its mass in grams? (Hint: There are 16 ounces in one pound).

1 inch = 2.54cm =

= =

= 1Km 0.62mi

1L 1.06quart

1Kg 2.2 pounds

1oz 28g

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1 inch = 2.54cm = = = = 1Km 0.62mi 1L 1.06quart

1Kg 2.2 pounds

1oz 28g

7. How many inches are in 72.0 meters? How many yards is this?

1 inch = 2.54cm = = = = 1Km 0.62mi 1L 1.06quart

1Kg 2.2 pounds

1oz 28g

8. In a track meet, Julian runs the 800. meter dash, the 1600. meter run, and the opening leg of the

4 ×400. meter relay. How many miles is this altogether?

1 inch 2.54cm

1Km 0.62mi

1L 1.06quart

1Kg _{2.2 pounds}

1oz 28g

=

9. How many liters are equivalent to 1.0 gallon? (There are exactly four quarts in a gallon.)

1 inch 2.54cm

1Km 0.62mi

1L 1.06quart

1Kg _{2.2 pounds}

1oz 28g

=

10. The mass of a large order of french fries is about 170. grams. What is its approximate weight in pounds?

1 inch 2.54cm

1Kg _{2.2 pounds}

1oz 2.8g

=

1 inch 2.54cm

1Kg _{2.2 pounds}

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1 inch 2.54cm

1Kg _{2.2 pounds}

1oz 2.8g

=

Physical Science

Chapter 1

Section 4

Working With Measurements

(2 parts)

Leaning Goals

*Determine the number of significant figures in measurements.

*Distinguish accuracy, precision, and resolution.

*Compare data sets to determine if they are significantly different

*In the real world it is impossible for everyone to arrive at the exact same true measurement as everyone else.

Find the length of the object in centimeters.

How many digits does your answer have?

*Digits that are always significant: *Non-zero digits.

*Zeroes between two significant digits. *All final zeroes to the right of a decimal point.

Digits that are never significant:

*Leading zeroes to the right of a decimal point. (0.002 cm has only one significant digit.)

*Final zeroes in a number that does not have a decimal point.

Significant Figures

How Many Sig Figs Are In Each Of The Following 145m

2097g

180mL

1.009Km

0.0072mg

0.008600cm

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Significant Figures In Calculations

*When adding or subtracting round to the least precise place value

*When multiplying and dividing, round to the least number of sig figs

Practice Problems

123m - 45.08m =

68.0g + 0.00098g =

8.5cm x 11.00cm =

110m / 4.00 =

Classwork

*1.4 Section Review Page 23 *#1 & 2

Homework *Worksheet

*Accuracy is how close a measurement is to the accepted, true value.

*Precision describes how close together repeated measurements or events are to one another.

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*In everyday conversation, “same” means two numbers that are the same exactly, like 2.56 and 2.56. *When comparing scientific results “same” means “not significantly different”.

*Significant differences are

differences that are MUCH larger than the estimated error in the results.

Significant differences

Error and significance

*How can you tell if two results are the same when both contain error (uncertainty)?

*When we estimate error in a data set, we will assume the average is the exact value.

*If the difference in the averages is at least

three times larger than the average error, we say the difference is “significant”.

Classwork

*1.4 Section Review Page 23 *#3 - 7