Science Inquiry Flashcards
Steps of the scientific method:
- Recognise a problem and define a question
- Collect as much info as possible relating to
the problem - Propose a hypothesis
- Test the hypothesis using an experiment
- Analyse and interpret the data collected
- Draw conclusions about whether the
hypothesis was supported or disproved
What is a hypothesis?
It is a definite statement which can be tested. It suggests a particular relationship between the independent and dependent variables. It is an educated guess, based on observation. Contains an individual idea that can be supported or disproved through experimentation.
How to write a hypothesis:
If we increase/decrease (choose one) the (independent variable) then the (dependent variable) will increase/decrease (Choose one).
What is a theory?
Contains one or more hypotheses that
have been supported with repeated testing.
Theories evolve as more information is
gathered.
What is a law?
Generalises a body of observations. Accepted as fact.
What is the independent variable?
The variable that is deliberately manipulated or changed to see what effect this has. It is also called the experimental or manipulated variable.
What is the dependent variable?
The variable or factor that changes as a response to the independent variable. This is what the experimenter observes or measures during the experiment.
What are controlled variables?
Those variables that are regulated and kept
constant for the duration of the experiment,
because they could have an effect on the outcome.
What are uncontrolled variables?
Those variables that are not controlled in the
experimental design. Sometimes they do not have any significant effect on the experiment, sometimes they will. It is always best to control all variables, except the dependent and independent variables, as much as possible. Sometimes you do not have access to equipment that will allow you to control all of the variables in this instance you will need to note this and discuss it in your report.
What is the control group?
Subjects all have the same conditions as the
other group, except for the variable being tested. The group to which nothing is done. Allows you to make a comparison with the experimental group. Controls are experiments which are set up in order to rule out the possibility of factors other than the variable under investigation being responsible for the changes observed. Often in experiments you will need some “normal” data to compare your results to. Scientists run a control group, where the conditions are what might be considered normal so that they can compare their experimental group data to the control group
What is the experimental group?
This group tests the hypothesis. The subjects are given one change in their conditions.
What is sampling?
A large sample size increases the reliability of
the outcome- it is an attempt to even out
individual variation that exists between
subjects. Specimens should be chosen randomly. Replication is needed to obtain a statistically reliable average. Experiments must run for a suitable time period.
What is the method?
Is what you actually did not what you planned to do (procedure) these may be two very
different things. Past tense, non-personal (no I, we, us), Clear and concise, Detailed.
What is repetition?
Doing the same experiment many times
What is replication?
Running numerous identical experiments at the same time or experimenting on a large number of subjects at the same time.
Reliability in an experiment:
Consistently similar results demonstrate that the results are reliable, they do not make data more accurate
Validity of results:
The degree to which the experiment tests
what it is supposed to. The more you control the variables and the less uncontrolled variables there are the more the valid the results are.
Reliability of results:
The extent to which the experiment gives the same results each time. Relies on well controlled variables and accurate equipment. Conducting more trials makes your data more reliable a it reduces the impact of anomalies
Collecting data:
Quantitative data
* Numbers, generally measurements
Qualitative data
* Observations that do not involve numbers
- Generally quantitative data is preferred but it is not always possible to collect data in this way
Results table layout:
- Results must be recorded in a suitable table.
- Title: A table showing…
- Appropriate headings
- Units with the headings- not in the body of the table
- Generally multiple results are taken and the average is calculated
What is the use of graphing?
Represents the relationship between at least
two sets of data. Allows predictions to be made from data. Make trends easy to see.
How to graph:
- Plot the independent variable on the x axis
- Plot the dependent variable on the y axis
- Label each axis clearly (variable and units)
- Give the graph a title which must include both the independent and dependent variables and the relationship
- Draw at least ¾ of page, data must fill at least ¾ of the axis.
- Choose your scale carefully.
- Choose the type of graph to suit the data.
What is interpolation and extrapolation?
- Interpolation - read a value from within your
graph - Extrapolation - when you use your graph to
predict a value beyond the data - Interpolation is more reliable than extrapolation
What to include in the discussion:
Results analysis:
* Address the question that your research was trying to answer
* Was there a relationship between variables
* Describe trends in your data (graph)
Scientific knowledge:
* You need to explain your results in terms of the scientific research you have done in class and in your literature review
Reliability of your data:
* Reliable data has very similar values each time the test is repeated
* The closer the values the more reliable the data
* Discuss in detail how close the repeats are too each other/average
Validity of results:
* Results are valid if they test what they were designed to test
* Basically the more tightly controlled your variables are, the more valid your results will be
* How did you ensure variables were controlled?
* Explain any anomalies
Experimental errors:
What things occurred that may have lead to your results not being as reliable or valid as they could be?
How would you overcome this in future
investigations
