Post on 14-Dec-2015
Controlling Variables
Hypothesis
The hypothesis is an educated guess about the relationship between the
independent and dependent variables.
Let’s learn about the 3 types of variables!
The 3 types of variables!
Independent Variable• Independent Variable – the one thing that is
changed in an experiment–What is tested–What is manipulated
Dependent Variable• Dependent Variable: the variable that is
affected by the change in the independent variable–What is measured–What is observed– The data collected during the investigation– the factor that may change as a result of
changes made in the independent variable.
Controlled Variables• Constant: a variable that is not changed–Also called controlled variable–Allows for a “fair test”
• Control group: exposed to the same conditions as the experimental group, except for the variable being tested.
• Serves as the standard of comparison.• The control group may be a “no treatment" or
an “experimenter selected” group.All experiments should have
a control group.
Identify the variables:• Hypothesis: If we add more air, the ball will
bounce higher.– Independent variable:• the amount of air in the ball
– Dependent variable: • How high the ball bounces
– Controlled variables: • type of ball, drop the ball from the same height, drop the
ball on the same surface
Identify the variables:• Hypothesis: If a plant gets sunlight it will
grow taller.• Independent variable: – sunlight
• Dependent variable: – Growth of plants
• Controlled variable: – Type of plant, pot, dirt, water, location, fertilizer