Scientific Inquiry

What is Science?What is Science?

What is Science?

A body of knowledge A set of theories that describes the world

A way of learning about the world

A method to answer questions about the natural world

How do Scientists Learn About the World?1.Ask a question2.Make a prediction3.Test the prediction4.Compare results to the

prediction5.Make a conclusion6.Hypothesis is either

rejected, or supported

The Scientific Method-ask a question

Only questions which can be answered through experiments. Examples of good scientific questions: How does the amount of nitrogen fertilizer affect the height of pea plants?

Does increasing the temperature of an enzyme increase its rate of reaction?

Write a Good Scientific Question.

Scientific Method-make a prediction Make a prediction

A scientists prediction about the results of an experiment is called the hypothesis

The hypothesis must be testable and specific and always written as a statement

Hypotheses usually begin with “I think that……” or “If…………then…………”

Example: I think that the more fertilizer that a pea plant gets, the taller it will grow

Scientific Method-test the prediction Controlled Experiments

Used by Scientists to test their hypothesis

Always have at least two groups:Control Group- stays the sameExperimental Group- changes, receives some sort of treatment

How are the control group and the experimental group different?

1.

2.

Scientific Method-compare results Scientists analyze the data collected

Data is information Compare the data from the control group with the experimental group

Use statistics to see if there is significant difference

Example- the pea plants in the experimental group grew an average of 18.3cm, while the control group grew an average of 12.6cm

Scientific Method- make a conclusion

Examine data, charts, graphs, to determine if the hypothesis is supported or rejected

Could the differences be due to chance? Use statistics to tell

Scientific Method- hypothesis rejected or supported?

If supported, repeat experiment to see if it is valid ( able to be repeated with the same results)

If rejected, then come up with a new hypothesis and experiment, repeat the process

Controlled Experiments- variables Three types of variables:

Independent- the thing that is different between the experimental and control group

Dependent- the data you collect as your experiment progresses, depends on the independent variable

Controlled- remains the same

I set up an experiment with 30 pea plants. I give 10 plants no fertilizer, 10 plants 5g. of fertilizer, and 10 plants 15g. of fertilizer. After 14 days I measure the height of the plants.

What is the independent variable? The amount of fertilizer

What is the dependent variable? The height of the pea plants

What are the 2 controlled variables? The amount of soil and water

What is the control group? Plants with no fertilizer

What is the experimental group? The two groups of plants getting fertilizer

What makes a good experiment? Large number of samples Only one independent variable

Validity Conclusions based on evidence

Is based on fact, not opinion

Design an Experiment ! Think of an experiment to test the hypothesis that sleeping more than 8 hours a night improves a students grades on Science quizzes! Control group: Experimental Group: Independent Variable: Dependent Variable: Controlled Variables: