INTRODUCTION TO SCIENCEChapter 1

Physical Science

A. The Nature of Science1. How does Science Happen?

a. Scientists investigate

b. Scientists plan experiments

c. Scientists observe

1. Observation: the use of one or more of your five senses to

perceive an object or event

d. Scientists always test results

e. Science has many branches

1. Science: a system of knowledge based on facts or principles

2. Science is broken down into social sciences and natural sciences

a. Natural sciences: biology, physical, and earth

b. Physical sciences: chemistry and physics

f. Science and technology work together

1. Technology: the application of science to meet human needs

2. Technology and science depend on one another

2. Scientific Theories and Laws

a. Theories and laws are supported by observations

1. Scientific theory: a tested, possible explanation of a natural event

a. Theories are always questioned

b. To be valid, must continue to pass several tests

c. Must be repeatable

2. Scientific law: a summary of an observed natural event

a. Doesn’t explain why!

b. Mathematics can describe physical events1. Many different languages are used in

the science community, but mathematics is the same everywhere

c. Theories and laws are not absolute

1. Sometimes theories have to be changed or replaced completely

d. Models can represent physical events

1. Model: is a representation of an object or event that can be studied to understand the real object or event

2. Represent things that are too big or too small

B. The Way Science Works1. Science Skills

a. Critical Thinking1. Critical thinking: applying logic

and reason to observations and conclusions

b. Using the scientific method1. Scientific method: a series of

logical steps to follow in order to solve problems

2. Helps you find and evaluate possible answers3. Used for everyday situations and scientific questions

4. First step, starts with making observations

5. Next step, forming a hypothesis

a. Hypothesis: a possible answer that you can test in some way

c. Testing hypothesis1. Done through

experiments

2. Variable: anything that can change in an experiment

a. Good experiments test only one variable at a time

b. If you change more than one variable, might be harder to recognize the answer

d. Conducting experiments1. Experiments give us results that will

support or refute our hypothesis

e. Using scientific tools

1. Items such as microscopes, telescopes, spectrophotometers, and other help scientists with observations

2. Units of Measurementsa. International system

of Units (SI) is used for everyone to understand

b. SI units are used for consistency1. Based on the metric system and makes thing easier2. Derived units: combinations of the base units

a. Area is an example (l x w)

c. SI prefixes are for very large and very small numbers

1. Helps to express numbers which would have too many zeros because it is too big or small

d. Making measurements

1. Length: the straight-line distance between any two points

a. Meters (m) is the SI unit

2. Mass: a measure of the quantity of matter in an object

a. Kilogram (kg) is the SI unit

3. Volume: a measure of space, such as the capacity of a container

a. Cubic meter (m3) is the SI unit

4. Weight: the force with which gravity pulls on a quantity of matter

5. For time, the SI unit is seconds

C. Organizing Data1. Presenting Scientific Data

a. Line graphs are best for continuous changes

1. Shows what occurs between two variables

b. Bar graphs compare items

1. Allows you to compare data for several individual items or events

c. Pie charts show the parts of a whole

2. Writing numbers in Scientific Notation

a. Scientific notation: a value written as a simple number multiplied by a power of 10

1. Example: 101=10, 102=100, 103=1000, 10-1=0.1, 10-2=0.01, 10-3=0.001

Example:

b. Using scientific notation

1. When you multiply numbers you add the powers, when you divide the numbers, you subtract the powers

3. Using Significant Figures

a. Precision: the degree of exactness of a measurement

b. Significant figures: the digits in a measurement that are known with certainty

c. Accurate: the extent to which a measurement approaches the true value

1. A measured quantity is only as accurate as the tool to make the measurement

Precision/accuracy example:

2. When calculating measurements, the answer is only precise as the least precise measurement (smallest significant figures)

a. Example: 5.87m x 8.14m = 47.7818

1. 47.8 m2 is the answer in significant figures