TOPIC 1 NOTES – HOW SCIENTISTS WORK

Essential Question - ______

Objectives:

Evaluate a scientific investigation using evidence of scientific thinking.

Analyze an experimental procedure to identify a design flaw and propose a method for correcting it.

Identify test (independent) and outcome (dependent) variables in an experiment.

How Scientists Work

Observing / Scientists gather information by using the senses or tools that enhance the senses.
Questioning / When scientists become curious about something they have observed they ask questions they would like to explore.
Forming Hypotheses / A hypothesis is a proposed explanation for the question
Investigating / Scientists test their hypotheses by conducting investigations or experiments or by creating models.
Analyzing Data to form Conclusions / Scientists organize and analyze the evidence obtained in their investigations using tables and graphs. They use that information to evaluate their hypotheses. The data collected can support or reject a hypothesis, but it will never prove it.
Repeating Investigations / Scientists repeat their experiments many times. These repetitions are called trails. Results should always be the same in order for data to be considered valid.
Sharing Results / Scientists share the results of their investigations with other scientists so that their work can be replicated and confirmed.

Scientists investigate and learn about the natural world in many ways:

______

Conducting Investigations

Making Models

Why do scientists conduct controlled experiments?

______

______

All reliable experiments have each of the following components:

Test Variable (Independent Variable)– the single factor that is changed, by the experimenter, to make the experimental groups different from each other.

Outcome Variable (Dependent Variable)– The variable that is measured by the experimenter in the experiment.

Constant Variables – Variables that are purposefully kept exactly the same between each group in the experiment.

*If every variable in the experiment, except the test variable, is not controlled, ______.

EXAMPLE:

How does applying fertilizer to plants weekly affect the height to which plants will grow?

If an experiment were conducted to investigate this question…

Plant Height
Group A / Group B
Week 1 / 5 cm / 5 cm
Week 2 / 7 cm / 9 cm
Week 3 / 10 cm / 13 cm
Week 4 / 12 cm / 17 cm
Week 5 / 13 cm / 23 cm
Week 6 / 14 cm / 28 cm

What would be the test variable (independent variable) in this experiment?

What would be the outcome variable (dependent variable) in this experiment?

What would be the controlled variables in this experiment?

What conclusion can be made based on the data collected in this experiment?