The Nature of Science

Objective

COS 12.0 Identify the metric units used for mass, temperature, time and length (distance)

What is science?

the knowledge obtained by observing natural events and conditions in order to discover facts and formulate (devise or create) laws and principles that can be verified (confirmed).

In other words science is simply the observing, studying and experimenting to find out how or why something works.

Types of sciences

Social science – any type of science that deals with individual or group human behavior Examples: anthropology, psychology

Natural science – any type of science that deals with understanding the behavior of the universe Examples: life sciences, physical sciences,

earth sciences

Natural Sciences

1. Life science – any type of science dealing with living things.Examples: Biology (which you have all taken),

Zoology (the science of animals), Botany (the science of plants)

2. Earth science – any type of science dealing with the earth, its atmosphere or spaceExamples: Geology (the science of the physical

nature of the earth and its history), Meteorology ( the science of the atmosphere and weather)

3. Physical Science

the class you are taking :-) physical science – any type of science

dealing with matter and energy. Examples: Chemistry (the science of

matter and its changes), Physics (the science of forces and energy)

Warning – both chemistry and physics depend greatly on MATH!!!!!!

Scientific Law vs. Scientific Theories

scientific law – a summary of that experimental results and observations OR a process in nature that can be tested by repeated experiments and allow predictions to be made about how a system will behave under a wide range of conditions

In other words, any event in nature in which the process can be described and tested by repeated experiments is known as a scientific law.

Scientific laws tell how a things work!

Scientific Laws vs. Scientific Theories Scientific laws can be stated in two

ways: qualitative statements or quantitative statements A qualitative statement is one that

describes an event in words A quantitative statement is one that uses

a mathematical equation Often a scientific law can be explained

as a mathematical equation!

Scientific Laws vs. Scientific Theories Scientific theory – an explanation of

some phenomenon (event) that is based on repeated observation, experimentation, and reasoning

Scientific theories are always being questioned and examined.

Scientific Laws vs. Scientific Theories For a scientific theory to remain valid

it must always pass several criteria:1. a theory must always explain an

observation clearly and consistently (again and again)

2. the experiments that illustrate the theory must be repeatable.

3. you (the scientist) must be able to predict (calculate or foretell) from the theory.

Scientific Laws vs. Scientific Theories Scientific laws and theories are always being

tested. As our knowledge base improves, scientific

theories are often being changed or replaced.Example: over 200 hundred years ago, scientist

used the ‘caloric theory’ to explain how objects became hotter or colder. The ‘caloric theory’ simply states that heat was an invisible fluid (called caloric) that would flow from hot objects to cooler objects. During the 1800s (after many experiments) a new theory (later called the kinetic theory) was suggested based on the idea that heat was the result of the motion of particles.

Scientific Method

To help with thinking critically about a situation scientist often uses the scientific method.

Scientific method – a series of steps followed to solve problems

Scientific Method

The scientific method is composed of 5 steps.1. observe a situation in nature2. Develop a question3. formulate a hypothesis (a possible answer

for the question being asked)4. research and collect data5. test the hypothesis

Record all observations while the test are running

6. draw a conclusion

Testing the Hypothesis

Scientist test a hypothesis by doing a series of ‘controlled experiments’.

In a controlled experiment all of the variables that can affect the outcome of the experiment are kept constant (or controlled) except for one.

Definition: variable – a factor (aspect or feature) that changes in an experiment in order to test a hypothesis.

When testing an experiment remember NO EXPERIMENT IS A FAILURE, even if the results are not as expected.

Units of Measurement

Often scientific observations rely on mathematical data or measurements.

Scientist use a common system of units for measurement known as the International System of Units (or SI units for short) which is based on the metric system.

Units of Measurement

SI units are based on the metric system and use the seven base units listed below. (these base units do not include all of the SI units we will eventually learn)Length meter mMass kilogram kgTime second sTemperature Kelvin KElectric current ampere AAmount of a substance mole molVolume liter L

Units of Measurement

Now to save time and having to write a lot of zeros, scientist often use prefixes to show very large or small measurements

Common large prefixes kilo- k thousand 1000 mega- M million 1000000 giga- g billion

1000000000

Units of Measurements

Common small prefixesdeci- d tenth0.1centi- c hundredth 0.01milli- m thousandth 0.001micro- u millionth 0.000001nano- n billionth 0.000000001

Keep in mind that it takes more of a smaller unit then a large unit (confusing right)Example: 1.67 m = 167cm

3.2 kg = 3200g = 3200000mg

Units of Measurement

Additional examples:A role of copper wire contains 15 m of

wire. What is its length on centimeters?○ There are 100 cm in 1 meter so…○ 15 m x 100 cm = 1500 cm

1 m A ball weighs 63975 mg. how much does

the ball weigh in grams?○ There are 1000mg in 1 g so…○ 63975 mg x 1 g____ = 63.975 g

1000 mg

Organizing Data

Graphs and Charts

Often when scientist are presenting data they use a variety of different graphs and charts to organize their data

The three main types of graphs are: Line graphs Bar graphs Pie charts

Line graphs

Line graphs are best for presenting data that changes.

Line graphs utilize two different variables (an independent variable and a dependent variable) when displaying the results.Definition: independent variable – the variable

(usually time) that is measured at set intervalsDefinition: dependent variable – the variable

that changes depending on what happens during the experiment.

Bar Graphs

A bar graph is used when scientist want to compare similar data for several different items.

A bar graph will make it clearer how large or small the differences in individual values are.

Pie Chart

A pie chart is used for displaying data that is part of a whole.

Pie charts values are often shown as percentages.

Scientific Notation

Sometimes a scientist needs to express measurements using numbers that are very large or small.

To reduce the amount of zeros that need to be written scientist will sometimes express a value as a simple number multiplied by a power of 10, in a process known as scientific notation.

Definition: scientific notation – a method of expressing a quantity as a number multiplied by 10 to the appropriate power.

Scientific Notation

Listed below are some of the powers of 10 and their decimal equivalent (comparable or equal to)103 = 1000102 = 100101 = 10100 = 110-1 = 0.110-2 = 0.0110-3= 0.001

Scientific Notation

Examples:The distance between Earth and Neptune is

4500000000000 m apart at a given time. What is the distance expressed in scientific notation?○ To get what your power of ten would be simply

count how many times you would have to move the decimal to get 1 whole number (any number between 1 and 9) in front of the decimal.If you move the decimal to the left the power is

expressed as a positive number.If you move the decimal to the right the power is

expressed as a negative number.○ So…. 4500000000000 m = 4.5 x 1012 m