What is Science?
What is Science?
A body of knowledge
A set of theories that
describes the world
A way of learning about the
A method to answer
questions about the natural
How do Scientists Learn
About the World?
1. Ask a question
2. Make a prediction
3. Test the prediction
4. Compare results to the
5. Make a conclusion
6. Hypothesis is either rejected, or
The Scientific Method-ask a question
Only questions which can be
answered through experiments.
Examples of good scientific
How does the amount of nitrogen
fertilizer affect the height of pea
Does increasing the temperature of
an enzyme increase its rate of
Write a Good
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
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
Used by Scientists to test their
Always have at least two groups:
Control Group- stays the same
Experimental Group- changes,
receives some sort of
How are the control group and the
experimental group different?
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
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
Examine data, charts,
graphs, to determine if the
hypothesis is supported or
Could the differences be
due to chance?
Use statistics to tell
hypothesis rejected or
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
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
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
Large number of samples
Only one independent
Conclusions based on
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