Scientific Method 🔎

• Identifying variables

  • The independent variable is the factor that is being investigated. This means that it is the factor that is deliberately changed to determine how it affects the results. The independent variable may also be called the experimental variable or the manipulated variable.
  • The dependent variable is the factor that changes due to the changes made to the independent variable. It is sometimes called the responding variable.
  • Controlled variables are the factors that are kept the same for both the control and experimental groups in an experiment.
• Hypothesis


  A definite statement that requires investigation to collect evidence to support it, and must be testable
• Good hypothesis


  • Is a definite statement, not a question
  • Is short (much easier to test a simple hypothesis than a complex one)
  • Has a single idea that can be tested
  • Usually links the independent and dependent variables
• In most cases, the link in a hypothesis will be in the form of a trend
• Hypotheses about sweating and urine production


  • Sweating causes a decrease in urine production
  • Sweating increases urine production
  • Sweating has no effect on urine production
• During the experiment, the scientist observes and records all the information from the experiment. This information is called the data. Whenever possible, the results of an experiment should involve measurement, or quantitative data, and direct observation, or qualitative data.
• Validity of the method


  A valid method will fairly test the hypothesis so that the only factor that affects the results is the independent variable. This means that we can trust the conclusion from the data.
• Accuracy of the results


  How correct or true the measurements are. Accurate data is possible if the correct measuring equipment is used.
• Reliability of the results


  How similar the results for trials of the same test are. We are able to identify reliable results by conducting multiple trials and comparing the measurements. If the method is followed correctly each time, the variables are controlled, and the equipment used is appropriate, then the reliability of the results is increased.
• Types of error that may occur in an experiment


  • Human error
  • Random error
  • Systematic error
• Human error


  A mistake - for example, incorrectly reading the scale on an instrument, spilling some liquid before measuring the volume, or making a mistake in a calculation
• Human errors are not part of experimental error. They should be avoidable with sufficient care and checking.
• Random error


  Unpredictable errors that can occur in all experiments because no measurement can be made with absolute precision
• Random error


  • Stopping a stopwatch a little early or a little late when timing a task
• Reducing random error


  Taking several measurements and averaging them
• Systematic error


  Errors that occur because of the way in which an experiment is designed or due to problems with equipment, where a measurement will always be too high or too low
• Systematic errors cannot be reduced by averaging; the only solution is to change the experimental procedure or equipment.
• What are the steps in scientific research according to the Scientific Method?


  1. Make an observation and identify a research question
  2. Formulate a hypothesis
  3. Plan the investigation
  4. Collect and record data
  5. Analyze data
  6. Interpret data
  7. Communicate findings
• What characteristics must a research question have?


  It must be well defined, measurable, and controllable.
• What is a hypothesis?


  A possible explanation to answer a research question.
• How should a hypothesis be structured?


  It must be a short statement that tests only ONE idea.
• What should be done if a hypothesis is rejected?


  It should not be considered proven or correct.
• Can you provide an example of a good hypothesis for the question “Why do humans sweat?”


  Humans sweat to regulate body temperature.
• What are the key components of setting up an investigation?

  • Variables
  • Procedures
  • Recording data
  • Evaluating the data (Discussion)
  • Conclusion
• What is the role of controlled variables in an experiment?


  They are held constant to eliminate other factors affecting the outcome.
• What is the independent variable in an experiment?


  It is what is varied during the experiment.
• What is the dependent variable in an experiment?


  It is what will be measured during the experiment.
• What is a control group?


  It is a treatment where the independent variable is eliminated or set at a standard value.
• Why is it important to conduct experiments safely and ethically?


  To ensure voluntary participation, informed consent, and minimize risk of harm.
• What are the conventions for constructing data tables in scientific research?


  • Title includes both independent and dependent variables
  • Data for independent variable in the left column
  • Data for dependent variable(s) in the right column(s)
  • Each column must have a heading and unit of measure
• What are the rules for constructing graphs in scientific research?


  1. Title conveys the relationship between variables
  2. Utilize most of the page
  3. Use a sharp pencil
  4. Independent variable on X-axis
  5. Dependent variable on Y-axis
  6. Label axes with measurements and units
  7. Use equal intervals for scale
  8. Include a key for multiple graphs
  9. Avoid extrapolation from non-zero starting points
• What is the purpose of a line graph in human biology?


  To show continuous data and trends over time.
• What is a histogram used for?


  To represent a frequency distribution of certain characteristics.
• What is a pie chart used for?


  To show proportions of a whole for discrete data.
• What is a scatter plot used for?


  To display continuous data and relationships between multiple variables.
• What should be done if the data does not support the hypothesis?


  • Consider why the results differ
  • Repeat the experiment if necessary
  • Collect more data or design a new experiment
  • Compare findings with other scientists
• What is reliability in scientific research?


  It refers to the consistency of results across multiple trials.
• What is validity in scientific research?


  It measures whether the experiment tests what it is supposed to test.
• How can reliability and validity be improved in experiments?


  • Repeat experiments
  • Use a large sample size
  • Control as many variables as possible
  • Ensure accurate and correct testing