Chapter 1Lesson 2

“The Scientific Method”

Key Concepts…

What is the scientific method?

What is the SI System?

Why should we learn the SI System?

I. What is the Scientific Method? (Ex. Pg. 13)

A. An organized plan used to help solve a problem.

B. The General Idea…

-Use your senses.

“The lights went out in my room…”

-What do you want to know?

“What caused the lights to go out?”

-Find out any information.

“Check to see if other lights work.”

-Make an educated guess using what you already know.

“The lights went out because ___________.”

Observations

Ask a Question

Research

Form a Hypothesis

-Run a controlled experiment.

Keep all variables the same and change only one.

Turn on other lights, blown fuse, broken bulb…

-Look at the data and facts.

No other lights work; it is storming outside

Conclusion: Lightning/wind broke a power line

*If no good answers are available go back and find more research and start the process over again.

Test / Experiment

Draw Conclusion

II. Using Scientific Notation

A. A way of expressing a number as a value and a power of 10.

1. Why use it???

-easy to use large/small numbers

a. 400,000,000

b. 35,300

c. 0.0000456 d. 4.58 x 10-3

4.0 x 108

3.53 x 104

4.56 x 10-5

0.00458

Activity (5-7 min)

1. Use a pen/pencil and measure the length of the table you are sitting at.

2. Record your measurement

3. Repeat using a different pen/pencil

4. Record your measurement

Think…Why are your measurements different from each other???

III. Standards of Measurements

A. Standard – an exact quantity that people agree on.

1. Ex: a

= 12 inches

2. a mile = 5280 feet

IV. Different Systems

A. English System – feet, gallons, cups, inches…

1. U.S. only country to use it.

B. SI System

1. 1960 by the French

2. Used worldwide

3. Based on powers of 10

Common Prefixes (pg. 17)Giga 109 1,000,000,000Mega 106 1,000,000Kilo 103 1,000Hecto 102 100Deka 101 10Base 100 1Deci 10-1 0.1Centi 10-2 0.01Milli 10-3 0.001Micro 10-6 0.000001Nano 10-9 0.000000001

Value 109 108 107 106 105 104 103 102 101 100 10-1 10-2 10-3 10-4 10-5 10-6 10-7 10-8 10-9

Symbol G M k h D d c m µ n

Prefix Giga X X Mega X X kilo hecto Deca Base Unit deci centi milli X X micro X X nano

Meter Liter Gram Second Mole Ampere Kelvin Celsius Candela

Examples

1. Convert 1.0 m to dm? 10 decimeters

2. A road is 1000 m in length. What is this in km?

1 kilometer3. A small new planet is found 3 light years

away from Earth. If the diameter of this planet is 23,500 meters, how many kilometers is its diameter?

23.5 kilometers

Assignment 1.2

1. 2.3 millimeters centimeters

2. 4.05 kilometers meters

3. 5.7 micrometer millimeters

4. 10.01 Megameters kilometers

5. 0.0003 hectometers millimeters

6. 1,234,567 micrometers Megameters

7. 1.34 x 103 deciliters liters

Answers to previous:

1. 0.23 cm

2. 4050 m

3. 0.0057 mm

4. 10010 km

5. 30 mm

6. 0.000001234567 Mm

7. 134 L

SI System Introduction

mg

Prefix Unit measured

milli gram

Length

A. Def – the distance between 2 points

1. base unit = meter

2. Ex: meter, millimeter, hectometer

Volume (derived unit)

A. Def. – the amount of space occupied1. formula: length X width X height

a. Must be same units2. base unit = liter (liquids); meter (solids)

a. **1 cm3 = 1 ml** 3. solids are always cubed (cm3, m3)4. is a derived unit

Volume Example

A liquid is poured into a container. If the dimensions of the container are 45 cm, 54 cm, and 80 cm what is the volume of the liquid in cm3?

194,400 cm3

The sides of a box are 45 cm, 54 cm, and 0.4 dm. What is the volume of the box in cm3?

9,720 cm3

Mass

A. Def. – the amount of matter in an object

1. base unit = gram

2. kilograms is used frequently

Density (derived unit)

A. Def. – Mass per unit of volume

1. formula: density = mass / volume

2. is a derived unit

Density Example

What is the density of an unknown metal that has a mass of 178.0 grams and a volume of 20.0 mL?

***Remember D=M/V***

8.9 grams/mL

Will this object float in water??? (1.0 g/ml) NO

Time and Temperature

A. Def. – Time is the interval between two events.

1. Base unit = second

B. Def. – Temperature is the amount of heat contained in a substance

1. Base unit = Kelvin/Celsius

Temperature Scales

a. Celsius Scale – used for most scientific worki. 0 = freezing point of waterii. 100 = boiling point of wateriii. 20 = room temperatureiv. 37 = body temperature

b. Kelvin scalei. 0 on the Kelvin Scale is absolute zero (-273 C.)ii. to convert Celsius to Kelvin add 273 Kiii. to convert Kelvin to Celsius subtract 273 K

Temperature Example

The outside temperature is 29 degrees Celsius. What is it in Kelvin?

302 Kelvin

A person has a temperature of 313 Kelvin. Does this person have a fever?

yes; the body temp is 40 deg C.