Download Writing a Hypothesis

Writing a Hypothesis
• What is a Real Hypothesis?
• A possible explanation to some
phenomenon or event
• It must be testable!
How are Hypotheses Written?
These are all possible hypotheses:
1. Chocolate may cause pimples.
2. Salt in soil may affect plant growth.
3. Plant growth may be affected by the color of
the light.
4. Bacterial growth may be affected by
temperature.
5. Ultraviolet light may cause skin cancer.
6. Temperature may cause leaves to change
color.
• Using the word “may” does not tell us
how we can go about testing the
hypotheses
Formalized Hypotheses
•
Use “if” and “then” statements
Contain two variables
1. Independent (manipulated)
2. Dependent (responding)
Independent Variable
• The variable the scientist controls
• Also called the manipulated variable
Dependent Variable
• The variable you observe or measure
• Also called the responding variable
If (responding variable) is related to
(manipulated variable) then
(prediction).
Example
• Skin cancer may be caused by
ultraviolet light.
Formal Hypothesis
• If skin cancer is related ultraviolet
light, then people with a high
exposure to uv light will have a higher
frequency of skin cancer.
Example
• Leaves may change color in the fall
because of the temperature.
Formal Hypothesis
• If the color change in leaves is
related to temperature, then
exposing plants to low temperatures
will result in the leaves changing
colors.