The Nature of Science

Taken over the centuries, scientific ideas have exerted a force on our civilization fully as great as the more tangible practical applications of scientific research.

I. Bernard Cohen

Definitions

Science is a way or a process used to investigate what is happening around you.

It can give us:

possible answers to questions

solutions to problems

A scientific theory is an explanation that is supported by facts.

Scientists use the word theory to describe ideas that have been well tested and have data that provides evidence for the idea .

Scientists also form laws , which are rules that describe a pattern in nature, like gravity.

Background Research / Information : Scientists research to find out what is already known about a topic; this helps in making a prediction or forming a hypothesi

Bar Graph : Used for showing comparisons

Bias : When personal opinions or points of view interfere with an investigation

Communication : Sharing the results of an investigation through presentations and journal articles

Conclusion : The final summary of an investigation; includes a restatement of the question and hypothesis, discusses the data, what the data means, problems with the research, ways to carry the research further, why the research is important

Control Group : A group that has nothing done to it; the independent variable is not used or applied to a control group so that it can be used as a comparison

Controlled Variables : Variables that could change, but are not allowed to; also called constants

Data Analysis : Reducing the data by finding the average, graphing the data and looking for relationships

Data Chart : A place for recording data; may be numbers or pictures

Data Collection : Writing down the observations and results of an investigation numerical data is recorded in data tables, other types of data are recorded in data charts

Data Table : A place recording quantitative data in rows and columns

Data : The observations and results of an experiment; in an experimental investigation, the dependent variable is the data

Dependent Variable : In an experimental investigation, what is observed and measured; the data

Descriptive Research : Research based on observations

Experimental Design : The plan for deciding how to answer a scientific question; the materials and procedures used to conduct an experiment

Experimental Research : Investigations that involve variables

Independent Variable : The variable that is changed or tested by the scientist; the thing that is different between experimental groups

Line Graph : Used for showing changes or trends

Materials : The supplies used to conduct an investigation

Pattern : Data that repeats itself in a similar way

Prediction / Hypothesis : Educated guesses about how an investigation will turn out. A hypothesis is a special kind of prediction - it is a prediction about the relationship between variables

Procedure : The step-by-step instructions for conducting an investigation; includes what and how variables will be changed and measured; includes repeated trials

Qualitative : Data that describes qualities or characteristics - color, sound, taste.

Quantitative : Data that is numerical; usually gathered using tools - mass, distance, volume, time, temperature.

Question / Problem : What the scientists is trying to find out; called the Research Question

Relationship : The effect of one variable on another; what the independent variable has to do with the dependent variable

Science Skills : Skills and processes used by scientists to help answer questions

Science : A way to solve problems and answer questions; a way of learning about the world around us

Technology : The application of science to make products or tools that people can use.

Trend : A general direction in data; a general increase or decrease in the data

How Science is Done

Observations are made in science. They are made by using:

Senses

Tools

increase accuracy & precision

Observations can be:

Qualitative

Describes qualities or characteristics

i Color

ii. Odors

iii. Sounds

iv. Textures

Quantitative

Numerical data

i. Mass

ii. Density

iii. Length

iv. Volume

v. Temperature

vi. Amount

Skills That Scientists Use Include:

Observing

Measuring

Classifying

Inferring

Predicting

Concluding

Hypothesizing

Modeling

Using mathematics

Defining operationally

Collecting data

Organizing data

Analyzing & interpreting data

Identifying variables

Manipulating & controlling variables

Designing experiments

Communicating

Scientific Methods are ways, or steps to follow, to try to solve problems and answer questions. Different problems and questions will require different scientific methods to solve them. There is no one 'right' scientific method.

Two General Types of Scientific Research:

Descriptive or qualitative research

Experimental research

Descriptive Research

Answers scientific questions through observation

Sometimes called qualitative research

Usually involves the following steps:

1. Stating and defining the Research Objective or Question

i. What you want to find out or what question you would like to answer.

2. Describing the Research Design

i. How will you carry out your investigation?

ii. What steps will you use?

iii. How will the data be recorded and analyzed?

iv. How will your research design answer your question?

v. What safety procedures are needed?

3. Eliminating Bias

i. Scientists may expect certain results. This is called bias. Good investigations avoid bias.

Avoid bias by:

Using careful numerical measurements for all data

Using random samples

4. Selecting Your Materials

i. Try to use the most up-to-date, accurate and precise materials available to them.

Using Models

In science models are used to represent things:

That happen too slowly

That happen too quickly

Are too big or too small

Are too dangerous or expensive

Models may be physical or computer-based

Experimental Research

Answers scientific questions by testing a hypothesis through the use of a series of carefully controlled steps

The "scientific method" is one way of solving problems - there is no one scientific method

Parts of experimental research include:

1. Stating a Research Question

Describe the question you want to answer
Very specific
1. Variables can be identified in the question

2. F orming a Hypothesis

A hypothesis is a statement that can be tested

States the effect of the independent variable on the dependent variable

Use prior knowledge, new information, and any previous observations to form a hypothesis

Null Hypothesis - a statistical hypothesis staing that the independent variable will not have an effect on the dependent variable

If, then statements are good for beginning scientists to use when writing a hypothesis

If, the independent variable is changed, then the dependent variable changes

3. Manipulating and Controlling Variables

Independent variables (sometimes called manipulated variables)

i. The variable that is changed by the scientist

ii.What is being tested

iii.The difference between experimental groups

iv.Tthe cause of the change in the dependent variable

2. Dependent variables (sometimes called responding variables)

i. The variable that is being observed and measured

ii. The data that is collected

iii. The 'effect' of the independent variable

3. Controlled variables (sometimes called constants)

i. The variables that are not allowed to change; those that are controlled by the scientists

ii. Variables that stay the same

iii. Allow the experiment to be a fair test

4. Controls, or Control groups

i. Sample that is treated like the other experimental groups except that the independent variable is not applied to it

ii. Provide a comparison group

5. Repeated Trials

i. Make sure that results are valid; not a "fluke"

ii. More trials = more reliability

4. Data Collection

Collected in charts and tables
i. Charts are used to record

Numbers

Pictures

ii. Tables are used to record

Numbers

In rows & columns

5. Data Analysis

Data is reduced

i. Measures of central tendency

Mean

Median

Mode

Range

Frequency

2. Graphs

i. Display so that trends, patterns and relationships can be seen

Trend - changes; increases, decreases in data

Patterns - repeated data that is similar

Relationships - how one variable affects another

ii. Bar graphs - used to show comparisons

iii. Line graphs - used to show changes & trends

iv.Allows us to see if data supports the hypothesis or not

i. If data supports hypothesis - accept the hypothesis

ii. If data does not support the hypothesis - reject the hypothesis

iii. You can still learn even if you do not get the results you expected

6. Conclusions

Discussion of what was learned during the investigation

Question & hypothesis are restated

Hypothesis is accepted or rejected

Data is used to provide evidence and support what is said

Problems or issues with the investigation are discussed

Questions for further research are explored

Discussion of the usefulness of the results; applications

7. Communication

Journals & presentations

Lets scientists share information - we can learn from each other

Measurement

Scientists around the world use a system of measurements called the International System of Units, or SI.

This allows them to understand each other's research and compare results.

Because SI uses certain metric units that are based on units of ten, multiplication and division are easy to do. Prefixes are used with units to change their names to larger or smaller units.

Measuring Length & Distance

1. Instrument is a ruler or meterstick

2. Basic unit is a meter (m)

3. Large distances - kilometers (km

4. Small lengths - centimeters (cm)

5. Very small lengths - millimeters (mm)

Measuring Volume - amount of space an object takes up

1. Instrument is a graduated cylinder

2. Basic unit is liter (l)

3. Most often used unit is the milliliter (mL)

4. 1 cubic centimeter (cc) = 1 mL

Measuring Capacity - amount an object can hold

1. Instrument is graduated cylinder

2. Basic unit is liter (l)

3. Most often used unit is the milliliter (mL)

4. 1 cubic centimeter (cc) = 1 mL

Measuring Mass - amount of matter in an object ; does not change

1. Instrument is triple beam balance

2. Basic unit is the gram (g)

3. Larger masses are measured in kilograms (kg)

Measuring Weight - the force exerted on an object by gravity ; changes with changes in gravity

1. Instrument in scale

2. Basic unit is the newton (N)

Measuring Temperature

1. Instrument is thermometer

2. Celsius or Centigrade scale

3. Water freezes a 0°C

4. Water boils at 100°C

Measuring Time

1. Instrument is stopwatch

2. Short times are measured in seconds

3. Longer times are measured in minutes or hours

The Nature of Science

Definitions

How Science is Done

Skills That Scientists Use Include:

Two General Types of Scientific Research:

Descriptive Research

1. Stating and defining the Research Objective or Question

2. Describing the Research Design

3. Eliminating Bias

4. Selecting Your Materials

Using Models

Experimental Research

1. Stating a Research Question

2. F orming a Hypothesis

3. Manipulating and Controlling Variables

4. Data Collection

5. Data Analysis

6. Conclusions

7. Communication

Measurement

Measuring Length & Distance

Measuring Volume - amount of space an object takes up

Measuring Capacity - amount an object can hold

Measuring Mass - amount of matter in an object ; does not change

Measuring Weight - the force exerted on an object by gravity ; changes with changes in gravity

Measuring Temperature

Measuring Time