Unit 1: Introduction
to Chemistry
The Scientific Method:
An organized approach to
solve problems.
(We do this all the time!)
Steps in the Scientific Method:
1.Observe
• Use your five senses
• Define the problem
2.Hypotheses
• “Educated guess”
• Reasonable explanations for what was
observed
3. Experiments
• Tests each hypothesis in order
to prove/disprove them
4. Analysis
• Compares the results from the experiment
to the original hypothesis
5. Conclusion (Theory)
• A hypothesis supported by experimental
evidence
Law:
Used to describe a natural
phenomenon which has been
tested over a long period of time
under different conditions.
You’re not going to
expect this...
Let’s try something to practice
the scientific method.
Coke vs. Diet Coke Demonstration
(1) Observation: Coke sank, Diet Coke floats
Observations
Coke
Observations
Diet Coke
(2) Hypotheses
In a colorless
liquid
In a colorless
liquid
Not the same liquids
Has caffeine
No caffeine
Caffeine more dense
Red can
Gold can
Weight of cans are
different
Contains sugar
Contains nutrasweet
Sugar is more dense
than nutra-sweet
Less carbonated
More carbonated
More CO2 makes the
can float
Coke vs. Diet Coke Demonstration
(1) Observation: Coke sank, Diet Coke floats
(2) Hypotheses
(3) Experiments and (4) Analysis
Maybe not the same
liquids
Switch the cans to see if the same
observation occurs
Caffeine more dense
Replace the caffeine-free diet coke
with a diet that contains caffeine
Different color of cans
(weigh different)
Weigh the cans on a balance
Sugar is more dense than
nutra-sweet
Weigh out the sugar, weigh out the
nutra-sweet
More CO2 makes the can
float
Collect the gas from each can
Coke vs. Diet Coke Demonstration
(1) Observation: Coke sank, Diet Coke floats
(2) Hypotheses
(3) Experiments and (4) Analysis
(5) Theory:
Maybe not the same
Switch the cans to see if the same
Since
39g of sugar is in regular
Coke
versus
liquids
observation
occurs
188mg
nutra-sweet
in Dietthe
Coke,
the regular
Caffeine
more
dense
Replace
caffeine-free
diet coke
Coke is more dense,
therefore
sinks.
withand
a diet
that contains
caffeine
Different color of cans
(weigh different)
Weigh the cans on a balance
Sugar is more dense than
nutra-sweet
Weigh out the sugar, weigh out the
nutra-sweet
More CO2 makes the can
float
Collect the gas from each can