How do we do Science?

Reminder: What is Science?The goal of science is to investigate

and understand the natural world, to explain events in the natural world, and to use those explanations to make useful predictions

Science is an organized way of using evidence to learn about the natural world

Reminder: What is Science?Science involves gathering data

through observation◦We create a research question about

the natural world inspired by observation

Scientists propose hypothesis (a scientific explanation for a set of observations)◦Hypothesis must be able to be tested◦New hypothesis must be considered if

observations and data demand it

The Scientific MethodScientists use the scientific method to

answer questions about the natural world◦State the Problem◦Form a Hypothesis◦Design and conduct controlled

experiments to test the hypothesis◦Make observations and collect data◦Draw conclusions based on results

Scientific MethodScience involves gathering data

through observation◦We state the problem we wish to

learn more aboutScientists propose hypothesis (a

scientific explanation for a set of observations)◦Hypothesis must be able to be tested◦New hypothesis must be considered

if observations and data demand it

Testing a HypothesisHow do we commonly test a

hypothesis? Experiments that generate data◦The factors that can change are

variables◦One item is changed (the

manipulated variable) while everything else is controlled to be the same

◦The variable that is observed is the responding variable

Which one of us is

changing?

Gather Data, Make ConclusionGathering data usually involves

measuring (results of the experiment)

Data should either refute or support your hypothesis- conclusion◦Both are valuable◦Disproving your hypothesis is not

“bad”Experiments are then typically

replicated to ensure the results/conclusions are accurate

Is One Experiment Enough to Prove Something?If we give 10 people a flu vaccine and

none of them become sick, does that prove that you can’t get the flu after the vaccine?

A key part of proving something scientifically is being able to replicate your experiment with the same results (or at least the same conclusions)

What if we can’t do an experiment?Can we do an experiment to study

how animals interact with one another in the wild?◦Can we control everything in the

wild?◦Researchers observe the animals

without disturbing them with field studies

What if we can’t do an experiment?Can we do an experiment on whether

a chemical causes cancer in humans?◦Study those who were exposed

versus people who were not

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Developing a TheoryAs evidence piles up, scientists may

begin considering a hypothesis a theory◦A theory is not considered absolute

truth, but it does have a large amount of evidence supporting it

◦If new evidence begins to be uncovered that a theory is incorrect it can be replaced or altered (Spontaneous generation versus life comes from life)

Spontaneous Generation Experiment

Scientific Method Videohttps://

www.youtube.com/watch?v=x2606GQmDqY