The stages of the scientific method
Bread goes mouldy sooner in the kitchen than in the pantry. Is it a coincidence, or is there an explanation? A scientist doesn't just stay puzzled: they turn the doubt into a question that can be investigated step by step.
The six stages
You see that a torch won't switch on, you think the batteries have run out, you put in new ones and check whether it lights up again: have you noticed that you've just solved an everyday problem using exactly the same stages as a scientist?
These steps of the scientific method are in the wrong order: (a) analyse data, (b) formulate a hypothesis, (c) experiment, (d) observe a striking fact, (e) draw…
These steps of the scientific method are in the wrong order: (a) analyse data, (b) formulate a hypothesis, (c) experiment, (d) observe a striking fact, (e) draw conclusions. Put them in the correct order and write one sentence explaining what is done in each step.
The diagram shows the steps of the scientific method, but one of them is hidden behind a question mark. Identify the missing step and explain what it involves.
The diagram shows the steps of the scientific method, but one of them is hidden behind a question mark. Identify the missing step and explain what it involves.
Explain in your own words the difference between a hypothesis, a scientific law, and a theory, and give an example of each related to falling objects.
Explain in your own words the difference between a hypothesis, a scientific law, and a theory, and give an example of each related to falling objects.
The hypothesis and the variables
To find out whether a fertiliser speeds up the growth of a plant, we can't change the fertiliser, the watering and the hours of light all at once, because afterwards we wouldn't know which of them caused the difference. How should we organise and classify the conditions of a test so that the conclusions are valid?
To test whether light affects growth, two identical pots are prepared with the same plant, the same soil, and the same watering: one is left in the sun and the other…
To test whether light affects growth, two identical pots are prepared with the same plant, the same soil, and the same watering: one is left in the sun and the other inside a dark cupboard. Identify the independent variable, the dependent variable, and two control variables (variables kept constant), and explain what role the plant in the cupboard plays.
A team plants a single seed in each condition and draws conclusions from what happens to it. Explain why this design is not reliable and reason how many seeds you would…
A team plants a single seed in each condition and draws conclusions from what happens to it. Explain why this design is not reliable and reason how many seeds you would use in each pot.
Fewer tadpoles have been spotted in a park pond since a fountain that stirs up the water was installed. Design an experiment to test whether water movement affects…
Fewer tadpoles have been spotted in a park pond since a fountain that stirs up the water was installed. Design an experiment to test whether water movement affects tadpole development: write the hypothesis, the experimental set-up, the control group, and what you would measure.
When the data do not confirm the hypothesis
The data from an experiment do not support the researcher's hypothesis. Explain what options she has (checking the procedure, repeating the measurements, reformulating…
The data from an experiment do not support the researcher's hypothesis. Explain what options she has (checking the procedure, repeating the measurements, reformulating the hypothesis) and why fiddling the data so they "come out right" is never an option in science.
A laboratory repeats the same experiment ten times and gets the expected result on only one occasion. Explain why the hypothesis cannot be considered proven and what the…
A laboratory repeats the same experiment ten times and gets the expected result on only one occasion. Explain why the hypothesis cannot be considered proven and what the team should do next.
To prove that its new fertiliser is "the best", a company fertilises fifty pots with its product and, after a month, announces that all the plants have grown. Point out…
To prove that its new fertiliser is "the best", a company fertilises fifty pots with its product and, after a month, announces that all the plants have grown. Point out at least three flaws in the experimental design and describe how it should be done correctly.
Back to the beginning: To investigate why bread goes mouldy sooner in the kitchen than in the pantry, you must keep the type of bread and its packaging identical (control variables) and vary only the location in order to compare the temperature or the humidity (independent variable), noting down how many days it takes for mould to appear (dependent variable).