How do scientists gain new
knowledge?
The scientific
method
It starts with observations of
something in the real world
Observation:
different objects fall at
different speeds. A piece of
paper practically floats to the
ground while a chunk of lead
plummets precipitously.
Questions:
The brain, being a lively and active
organ, immediately starts asking
questions about this.
Question:
Why do they fall at different
rates?
We then immediately try to answer our question,
based on our scientific knowledge and experience.
We haven’t proven that our guess (called an
hypothesis) is correct, but we try to be reasonable by
giving an answer that can be tested.
Hypothesis:
1. Heavier things fall faster because they are
more attracted to the earth
2. Things with greater surface area receive more
resistance and are therefore, slowed down
3. Objects which are denser fall faster because
they are not supported by the air as much.
4. Etc. There are many other possible hypotheses.
Experiment:
The next step is pick a reasonable hypothesis
and attempt to disprove the hypothesis by
doing something with relevant
materials in which we use only one
variable. We try to collect data which
other scientists will find convincing
Hyp: Things with greater surface area receive more
resistance and are therefore, slowed down
• Experiment:
1. Measure the time for the drop of a sheet
of unfolded paper compared to a twice and
thrice and 4x folded sheet .
2. Make sure that all conditions are the
same except the surface area of the sheets.
(All sheets must have same mass and be
dropped from same height, for example.)
3. Tabulate data and analyse.
Analyze the data: make tables and
graphs, compare averages, etc.
The idea is to see if the data
supports or rejects the hypothesis
Condition
Time to reach ground
Unfolded
1.1
Folded once
1.1
Folded twice
1.0
Folded three times
0.7
Draw a conclusion from the data
Conclusion:
The difference between unfolded
and once-folded is not noticeable,
but the thrice folded sheet
definitely falls faster. The
hypothesis that surface area
affects the speed with which the
object falls is supported.
Anton von Leewenhoek
Leewenhoek’s microscope:
eye side
object side
Assignment: read the
Leewenhoek biography, then
pick one of his experiments
and follow his scientific
process by filling out the
following form with complete
and detailed sentences.
His observation(s):
His question:
His hypotheses: (can be
plural)
His experiment(s):
His data and analysis:
His conclusion: