A Fair Test? The Scientific Method

Why do we want to test one variable at a time?

• Because it is hard to setup a data table with more than one
• It keeps the experiment fair and you can see what caused the change
• It is what has always been done
• It makes the results better in an experiment

Tags

NGSS.3-5-ETS1-3

The class set up an experiment to see how the type of ball affects the distance it rolls off a ramp. Identify the Independent Variable in this experiment.

• distance traveled by the ball

• height of the ramp

• the type of ball

A materials scientist wants to investigate which brand of trash bag can withstand the most amount weight before ripping. Identify the responding variable for the investigation.

• amount of trash bags

• brand of trash bags

• amount of weight

• same size trash bags

A materials scientist wants to investigate which brand of trash bag can withstand the most amount weight before ripping. Identify one possible control variable for the investigation.

• amount of trash bags

• brand of trash bags

• amount of weight

• same size trash bags

Factors that remain the same in an experiment to make it fair are called the

• controlled variables

• manipulated variables

• responding variables

• tested variables

An experiment is performed on plants to see how different liquids affect plant growth. Each plant in the experiment is given a different liquid; water, apple juice, or milk. Each plant has the same amount of soil, sunlight, and listens to the same music. In this investigation, the independent variable is ...

• The type of plant
• The amount of sunlight
• The type of music
• The type of liquid

Tags

NGSS.MS-LS1-5

An experiment is performed on plants to see how different liquids affect plant growth. Each plant in the experiment is given a different liquid; water, apple juice, or milk. Each plant has the same amount of soil, sunlight, and listens to the same music. In this investigation, what is the responding variable?

• Type of plant

• Water, apple juice, milk

• Plant growth

Some Biology students were experimenting with the effects of salt on plant growth. To do this, they watered plants daily with the same amount of salt water. They could best improve their experiment by

• increasing the amount of salt added to the water each day

• cooling the salt water before watering the plants

• adding food color to see how far the salt penetrates the plants

• watering half the plants with pure water and half with salt water

How many variables should a scientist change with each new experiment?

• 1
• 2
• 3 or more
• as many as he wants to

Tags

NGSS.3-5-ETS1-3

A Chemist would like to test the rate of heat conduction of different materials. They set up the apparatus below with different number of ice cubes and two plates of different materials. What should they do to ensure a fair test?

• Use the same type of plates and different number of ice cubes.

• Use the same type of plates and the same number of ice cubes.

• Use different types of plates and different number of ice cubes.

• Use different types of plates and the same number of ice cubes.