The Experiment
What is the variable that a scientist deliberately changes in an experiment?
What is the independent variable?
Which instrument could be used to determine the length of an object?
Metric ruler
How many variables are tested in a controlled experiment?
One
The definition of the dependent variable?
What is the variable you observe or measure?
Which axis is used for the dependent variable?
What is the y-axis?
A student sees dark clouds and predicts that it will rain soon. Is this an observation or an inference?
Inference
What units do you use to measure length of an object?
cm
A student tests whether different amounts of water affect plant growth. What are two variables that should be kept the same?
plant type, soil type, amount of sunlight, or pot size.
What is important about choosing a proper scale?
It must take up most of the graph and intervals should be consistent.
What is the difference between an observation and an inference?
An observation uses the senses or tools to gather information; an inference is an explanation based on observations and prior knowledge.
What are the units when measuring volume of a liquid?
mL
A graduated cylinder contains 25 mL of water. After a rock is added, the water level rises to 38 mL. What is the volume of the rock? Don't forget units!
13 cm
A student tests whether different amounts of water affect plant growth. What is the independent variable?
The amount of water given to each plant.
The curve a liquid forms in a hollow tube.
What is the formula for the volume of a regular shaped solid?
length x width x height
A scientist's results do not support the original hypothesis. What should the scientist do?
Report the results honestly, use the evidence to draw a conclusion, and revise the hypothesis or conduct further testing if appropriate.
The group that does not receive the test variable.
What is the control group?
A graph shows that as the number of hours of sunlight increases, plant height also increases. What relationship does the graph show?
Direct/Positive
What is the definition of volume?
the amount of space an object takes up
Which instrument could be used to determine the volume of a liquid?
graduated cylinder
A student tests whether fertilizer affects plant growth but gives the fertilized plant more sunlight than the other plant. Why is this an unfair test?
More than one variable was changed, so the student cannot determine whether fertilizer caused the difference in growth.