Knowt
C7 - Ideas About Science
The Scientific Method
Experimentation is all about finding explanations for observed phenomena. To experiment in an efficient and thorough manner, scientists use the scientific method.
The general steps to the scientific method are below.
Observe a phenomenon.
Form a question about your observation.
Make a hypothesis.
Hypothesis: a testable theory or explanation.
Experiment (and record data!)
Analyze data from experimentation and draw conclusions.
Communicate the results.
Planning Experiments
How can you test your hypothesis? In the field of chemistry, it is especially important to understand the purpose of various lab equipment, materials, and techniques.
Common Lab Equipment:
Flasks, beakers, and test tubes can all be used as containers in chemistry experiments.
Timers, rulers, pipettes, scales, thermometers, and measuring cylinders can be used for getting accurate measurements.
Common Lab Chemicals:
Water
Salts
Acids and Alkalis
Organic compounds
Some Examples of Common Lab Techniques:
If looking for a change in mass, a scale will likely be used in the experiment.
In an experiment involving temperature, use a thermometer.
If performing a titration, use a burette.
pH meters are used to record the pH of a solution.
Measurements
In chemistry, it is important to collect precise and accurate measurements.
Precision - how consistent values are to each other.
Accuracy - how close a value is to the correct or standard value.
To ensure validity, scientists also need to consider outside factors that may affect the phenomenon being looked at in an experiment.
To combat external factors, experiments are often performed in a controlled setting, like a lab.
Hazards and Risk
Another thing to consider when planning an experiment is safety. Think of ways your experiment may go wrong. What precautions should be in place in case something goes wrong?
Drawing Conclusions
Presenting Data
Data visualization can be very useful in communicating experimental findings.
Tables can show how two or more variables change through the experiment. Often, tables are used when collecting data during an experiment.
Charts can show data after it has been collected. Typically, charts are used to show patterns.
Graphs can show how data changes as an independent variable (such as time) changes.
Units
For consistency and ease of communication, scientists use a standard set of units called the Standard International (SI) units.
Some common SI units are meters, kilograms, joules, seconds.
SI units may also be used with standard prefixes. This is often done to avoid reporting extremely large or small numbers. The table below shows the most common prefixes:
Prefix Name | Symbol | Power |
|---|---|---|
tera- | T | x 1012 |
giga- | G | x 109 |
mega- | M | x 106 |
kilo- | k | x 103 |
centi- | c | x 10-2 |
milli- | m | x 10-3 |
micro- | μ | x 10-6 |
nano- | n | x 10-9 |
For example, instead of saying something is 0.000004 meters long, you may instead report it as 4 micrometers.
Scientific Explanations
Correlation and Causation
Correlation - a relationship between two sets of data.
Causation - a relationship between two factors, in which one factor changes because of changes in the other.
Correlation does not always mean causation, however. It is still important to consider external factors that may affect the outcome of an experiment. If there is no scientific explanation that supports a causal link between the two variables, causation cannot be determined.
Development of Scientific Explanations
Scientific theory - general explanation for a phenomenon that can apply to many situations.
Hypothesis - a testable explanation for a phenomenon
New data may contradict a hypothesis and lead to a new one being formed.
Peer Review - a process in which a scientist submits research for other scientists (usually in a similar field) to review. This ensures the validity and originality of published scientific research.
C7 - Ideas About Science
The Scientific Method
Experimentation is all about finding explanations for observed phenomena. To experiment in an efficient and thorough manner, scientists use the scientific method.
The general steps to the scientific method are below.
Observe a phenomenon.
Form a question about your observation.
Make a hypothesis.
Hypothesis: a testable theory or explanation.
Experiment (and record data!)
Analyze data from experimentation and draw conclusions.
Communicate the results.
Planning Experiments
How can you test your hypothesis? In the field of chemistry, it is especially important to understand the purpose of various lab equipment, materials, and techniques.
Common Lab Equipment:
Flasks, beakers, and test tubes can all be used as containers in chemistry experiments.
Timers, rulers, pipettes, scales, thermometers, and measuring cylinders can be used for getting accurate measurements.
Common Lab Chemicals:
Water
Salts
Acids and Alkalis
Organic compounds
Some Examples of Common Lab Techniques:
If looking for a change in mass, a scale will likely be used in the experiment.
In an experiment involving temperature, use a thermometer.
If performing a titration, use a burette.
pH meters are used to record the pH of a solution.
Measurements
In chemistry, it is important to collect precise and accurate measurements.
Precision - how consistent values are to each other.
Accuracy - how close a value is to the correct or standard value.
To ensure validity, scientists also need to consider outside factors that may affect the phenomenon being looked at in an experiment.
To combat external factors, experiments are often performed in a controlled setting, like a lab.
Hazards and Risk
Another thing to consider when planning an experiment is safety. Think of ways your experiment may go wrong. What precautions should be in place in case something goes wrong?
Drawing Conclusions
Presenting Data
Data visualization can be very useful in communicating experimental findings.
Tables can show how two or more variables change through the experiment. Often, tables are used when collecting data during an experiment.
Charts can show data after it has been collected. Typically, charts are used to show patterns.
Graphs can show how data changes as an independent variable (such as time) changes.
Units
For consistency and ease of communication, scientists use a standard set of units called the Standard International (SI) units.
Some common SI units are meters, kilograms, joules, seconds.
SI units may also be used with standard prefixes. This is often done to avoid reporting extremely large or small numbers. The table below shows the most common prefixes:
Prefix Name | Symbol | Power |
|---|---|---|
tera- | T | x 1012 |
giga- | G | x 109 |
mega- | M | x 106 |
kilo- | k | x 103 |
centi- | c | x 10-2 |
milli- | m | x 10-3 |
micro- | μ | x 10-6 |
nano- | n | x 10-9 |
For example, instead of saying something is 0.000004 meters long, you may instead report it as 4 micrometers.
Scientific Explanations
Correlation and Causation
Correlation - a relationship between two sets of data.
Causation - a relationship between two factors, in which one factor changes because of changes in the other.
Correlation does not always mean causation, however. It is still important to consider external factors that may affect the outcome of an experiment. If there is no scientific explanation that supports a causal link between the two variables, causation cannot be determined.
Development of Scientific Explanations
Scientific theory - general explanation for a phenomenon that can apply to many situations.
Hypothesis - a testable explanation for a phenomenon
New data may contradict a hypothesis and lead to a new one being formed.
Peer Review - a process in which a scientist submits research for other scientists (usually in a similar field) to review. This ensures the validity and originality of published scientific research.
