1. Lesson 1
March 6, 2012

2.  Ffdg

3.  Organism
 A living thing.
 Observation
 Gathering information in a careful, orderly way.
 Data
 Information gathered from observations.
 Inference
 A conclusion based on experience or evidence.
 Hypothesis
 A proposed explanation for observations.

4.  DESIGNING AN EXPERIMENT
 Asking a question
 Forming a hypothesis
 Doing a controlled experiment
 Recording and analyzing results
 Drawing a conclusion

5.  An EXPERIMENT…
 Can make a discovery.
 Can test a hypothesis.
 Can prove a known fact.

6.  Example: how do organisms come into being?
 In the past, observations showed that some living things
just appeared.
 Mice appeared in grain.
 Maggots appeared on meat.

7.  People thought that the mice came from the grain, and
the maggots came from the meat.
 This idea was called spontaneous generation.
 Do you think spontaneous generation is correct?

8.  A doctor named Redi had a different idea. He observed
that maggots appeared on meat a few days after flies
were around it.
 His hypothesis was that flies made the maggots.

9.  A hypothesis is a possible explanation based on
observations and evidence.
 All experiments begin with a hypothesis.

10.  Remember: an experiment tests a hypothesis.
 Redi wanted to test his hypothesis. He had to figure
out which variable to change.
 A variable is any part of the experiment that can change.
For example: equipment, material, temperature, light,
time.
 An experiment should only change 1 variable at a time.
 The variable that the scientist changes is called the
manipulated variable.
 The variables that change as a result of the manipulated
are called the responding variables.

11.  Here is Redi’s controlled experiment. What are the
controlled variables? What are the manipulated variables?
What are the responding variables?

12.  Controlled variables: jars, type of
meat, location, temperature, time.
 Manipulated variables: closing the jars
 Responding variable: maggots

13.  Redi observed that maggots appeared on the meat in
the open jars.
 No maggots appeared on the meat in the closed jars.
 He recorded his findings by writing them down for
future scientists.

14.  The conclusion uses evidence from the experiment to
state if the hypothesis was supported or refuted.
 Supported = hypothesis was correct.
 Refuted = hypothesis was incorrect.
 Was Redi’s hypothesis supported or refuted?
 What was his conclusion?

15.  Redi’s hypothesis was SUPPORTED.
 His conclusion: flies produce maggots.
 Spontaneous generation is incorrect.
 New organisms come from existing organisms. This is
called biogenesis.

16. What is a theory?

17.  If a hypothesis is supported by many different
experiments, it can become a theory.
 A theory is a well-tested explanation that brings many
observations together.
 Theories let scientists make better predictions about
new situations.
 Sometimes more than one theory is needed to explain
something. For example…

18.  …kangaroos and koalas!
Oy mate.
G’day
 Why are they only in Australia?

19.  The answer can be explained by 2 theories:
 Evolution (more later in this class)
 Plate tectonics (more later in Physics)

20.  Plate Tectonics
 Millions of years ago, Australia, Antarctica and South
America were all joined in one continent.
 This continent broke apart, and Australia became a
continent by itself.
 Evolution
 Organisms change over time to survive.
 Since Australia was so far away from other
continents, the animals in Australia changed in unique
ways