The Scientific Method

The Scientific Method
Science is the human effort to understand the natural
world and how it works, with observable physical
evidence as the basis of that understanding.
Vanessa Jason Biology Roots
The Power of Observation
Science begins with OBSERVATION.
How observant are you?
On a traffic light, is the green light found on the top, middle or
bottom? Bottom!
Which hand does Lady Liberty (the Statue of
Liberty) carry the torch in? Her right!
Why is having a methodical approach to
science useful?
Why bother with the scientific method?
Using a consistent, methodical approach to
solving a problem leads to the most accurate
results with the fewest mistakes!
The scientific method is something all of us use
all of the time -- being curious, asking
questions, seeking answers – these are basic
parts of the scientific method.
The Scientific Method is all around us
• Fixing a flashlight
• Fixing your internet connection
• Trying a new recipe for the first time
How are we
going to solve
this one,
Using the scientific
method, as we always
do, each and every
Inference, Hypothesis, Prediction
An inference is a logical explanation for something based on
prior experiences or knowledge.
Example: Grey skies mean rain; sore throats lead to the flu
A hypothesis is a possible explanation- it must be testable!
Example: Exercising will help me lose weight.
Prediction- A prediction is based on your hypothesis.
Set up your prediction as an “IF, THEN” statement.
Example: If I run 2 miles 5x a week for
6 weeks, then I will lose weight.
The Scientific Method
The Scientific Method is a series of steps in which
a question and/or problem is investigated by
observing and experimenting.
Step 1
Step 2
State the problem or pose the question.
Form a hypothesis (an
explanation or possible answer).
The Scientific Method
Step 3
Test your hypothesis.
In order to get accurate results from your experiment, it must
include two variables and a control group:
Independent (manipulated) variable: what is changed during
the experiment.
Dependent (responding) variable: what you measure during
the experiment.
Control group- a group that is NOT experimented on; left
alone to see what would happen without your manipulations so
that you can compare results.
Independent vs. Dependent Variables
Example- A new mosquito repellent is tested before it
hits the market. One arm is sprayed, the other arm is
NOT sprayed. After 6 hours, mosquito bites are counted.
Independent variable (or manipulated variable)- is what is
changed. In this case it is adding the mosquito repellent
to your skin.
The dependent variable (or responding variable) is what
you are measuring- the number of mosquito bites.
The control is what you left alone.
The control in this example is the arm that is NOT
Independent vs. Dependent Variables
A question might look like this:
mosquito repellent effect _________________
# of mosquito bites
How does __________________
(independent variable)
(responding or dependent)
Experimental Group
There are two groups in an experiment: the control and the
experimental group.
The experimental group shows the effect of the variable that
was tested.
Experiments should be designed to compare the results of the
experimental and the control groups.
In the mosquito repellent example,
which arm serves as the experimental group?
The arm with the repellent- it is going to show the effect of the
variable (the repellent).
The Scientific Method
Step 4
Analyze your data.
During this step, you’ll want to organize your
data by using charts and/or graphs.
Types of Data
Data can be quantitative or qualitative.
Quantitative= numbers (quantity)
Qualitative= descriptions (quality) (ex- colors,
health, appearance, texture, behavior, etc.)
Example: Gummy Bear Lab
How much a gummy bear weighs before and after
experiment= quantitative data
Overall appearance of gummy bear before vs. after
experiment= qualitative data
The Scientific Method
Step 5
Draw conclusions. This is the written
portion of your experiment in which you
share results and make connections.
When drawing conclusions, include if your hypothesis
was accepted or rejected.
-If hypothesis is rejected (unsupported), then it needs to
be modified.
-If the hypothesis is accepted (supported), the
experiment is typically repeated.
Scientific Method in Action
Question: Which brand of gum lasts the longest?
Trident®, Orbit®, or Eclipse®?
Which steps must be taken before designing the
-Collect data
-Form a hypothesis
How would you design the experiment?
Which steps follow the experiment?
-Analyze the data
-Draw conclusions
Design an Experiment!
Question: Does fertilizer increase the number of tomatoes
on a single tomato plant?
Tip: Use a higher number of plants… why?
Higher numbers give more accurate results!
Possible scenario:
5 tomato plants DO NOT
receive fertilizer.
Possible scenario:
25 tomato plants receive
Should fertilizer be the same
Design an Experiment
The only difference between the two groups should be
the addition of the fertilizer to the experimental group.
Everything else should remain the same.
Examples Same amount of water
 Same size pots
Why is this important?

similar documents