Independent and Dependent Variables

VARIABLES

something that is able to be changed or adapted

Independent Variables

what you change in a scientific experiment

Example

• Are students who are involved in school sports more likely to have a higher grade point average?

• The independent variable would be whether or not students are involved in school sports. Because that is what we can change.

Dependent variable

what changes because of the independent variable, what you are trying to figure out or understand

often the result of the experiment

Example

• Are students who are involved in school sports more likely to have a higher grade point average?

• The dependent variable would be the grade point average of the students who participated in the experiment.

• The dependent variable should be measureable or observeable.

Try to identify the independent and dependent variables in the following examples.

Multiple Choice

The variable that is measured.

It is the result of the experiment.

What we record as DATA...

• Controlled Variable

• Dependent Variable

• Independent Variable

Multiple Choice

TIME spent studying and your test SCORE.

What is the INDEPENDENT variable?

• Time spent studying

• Test score

Multiple Choice

What is the dependent variable in the question below?

Are children who learn to read before kindergarten more likely to attend college?

• when students learn to read

• likeliness to attend college

• what students read

Multiple Choice

Randall wants to know if the AMOUNT OF SALT in the water has an effect on his goldfish's COLOR.

What is the INDEPENDENT variable?

• amount of water

• number of goldfish

• amount of salt

• color of the goldfish

Multiple Choice

Here are the results of Tony's typing.

What is the INDEPENDENT variable?

• words
• minutes

Multiple Choice

If students spend more time using TikTok, then they will read fewer books. Identify the independent variable.

• amount of time on TikTok

• number of books read

• There isn't one.

Multiple Choice

Steve wanted to see if the type of fertilizer made sunflowers grow larger. What is the DEPENDENT variable? 

• Type of FERTILIZER

• SIZE of sunflower

• Amount of RAIN

Multiple Choice

What is the independent variable in the question below?

When students bring a packed lunch to school do they consume fewer calories?

• Whether or not students bring a packed lunch or eat a school lunch

• how many calories students consume

Multiple Choice

You are testing how the amount you water a plant affects its growth. What would be the INDEPENDENT VARIABLE in this experiment.

• They type of pot you put the plants in.

• The amount you water each plant.

• The amount of sunlight the plants get.

• The amount the plant grows.

Multiple Choice

Which TYPE OF FERTILIZER makes sunflowers GROW TALLER?

What is the INDEPENDENT variable? 

• Type of fertilizer
• height of sunflower

• type of sun flower

Multiple Choice

What is the independint variable in the question below?

Do movie goers eat more popcorn during comedies or dramas?

• the amount of popcorn eaten during the movie

• which movie is seen

Multiple Choice

Mr. Pransky wants to see how different surfaces affect how high a tennis ball can bounce. What is the independent variable?

• the different surfaces

• using the same ball

• how high they bounce

Multiple Choice

A cow is given a growth hormone and then compared to another cow that was not given a growth hormone. Both cows were weighed at 2 years. What is the INDEPENDENT variable?

• amount of time

• weight

• growth hormone

• type of cow

Multiple Choice

What is the dependent variable?

The speed of a car and the amount of time it takes to get to your destination.

• The speed of a car

• The amount of time it takes to get to your destination

Multiple Choice

What is the DEPENDENT variable (effect) in this experiment?

"Does eating breakfast improve test scores?"

• eating breakfast or not

• test scores

• wake up time

• how tasty the breakfast is

The independent variable is the growth hormone.

Remember that the independent variable is the one that we change on purpose. In this case, we give one cow growth hormone and the other gets no growth hormone.

Multiple Choice

A cow is given a growth hormone and then compared to another cow that was not given a growth hormone. Both cows were weighed at 2 years. What is the DEPENDENT variable?

• amount of time

• weight

• growth hormone

• type of cow

The dependent variable is the weight of the cow.

Remember that the dependent variable is the variable we measure (it DEPENDS on the other variable). In this case, we are measuring the weight of the cow to see if the growth hormone has affected it.

Control Variables

Some variables in this experiment are kept the same:
- Time (2 years)

- Type of cow
- Environment
It is important to keep all variables except the independent variable the same to get accurate results.

Multiple Choice

Mosquito repellent is sprayed on one arm and the other arm is not sprayed. The number of mosquito bites is counted after 2 hours.

What is the INDEPENDENT VARIABLE?

• which arm

• mosquito repellent

• time

• number of mosquito bites

Mosquito repellent is the independent variable.

We are changing whether the arm gets sprayed with mosquito repellent or not.

Multiple Choice

Ms. Shar is trying to decide where to seat Mya so she won’t talk as much during class. Ms. Shar moves Mya to different seats and tallies her shout outs in each location.

What is Ms. Shar measuring?

• Mya's seat

• How many times Mya shouts out

• The time of day

• The class

Multiple Select

Ms. Shar is trying to decide where to seat Mya so she won’t talk as much during class. Ms. Shar moves Mya to different seats and tallies her shout outs in each location.

What should Ms. Shar keep the same?

• Mya's seat

• How many times Mya shouts out

• The time of day

• The class

Ms. Shar wants to know the best plant food for her tomato plants. She tests four different types of fertilizer on four different tomato plants and measures their heights each day. She gives them the same sunlight and water.

Multiple Choice

If students spend more time using TikTok, then they will read fewer books. Identify the independent variable.

• amount of time on TikTok

• number of books read

• There isn't one.

Multiple Choice

In an experiment to find out how the temperature affects the bounce height of a ball, the dependent variable is ...

• temperature
• bounce height
• the thermometer
• the ruler

Multiple Choice

Should experiments be repeated over and over to see if the results are the same each time?

• yes
• no

Multiple Choice

The one variable in an experiment that is purposely changed and tested by the scientist is the________________.

• dependent variable

• independent variable

• data

• control group

Multiple Choice

Research Question: Does the type of gasoline put in a car affect how fast the car can drive.

What is the independent variable?

• Type of gasoline

• which car the gas is put into

• how fast the car can drive

• how much gas is put into the car

Multiple Choice

If I study for my scientific method quiz, then I will have a better test score. What is the dependent variable?

• Scientific Method
• Studying
• Independent variable
• Test score

Multiple Choice

In a line graph you will find the independent variable on .... axis and the dependent variable on .... axis

• x , y

• y, x

• they can be switched

Multiple Choice

What is the independent variable?

• cost of mowing
• Moe's Mowing Service
• $18
• Mowing Time

Multiple Choice

A testable prediction about a scientific investigation is a(n)

• Question
• Observation
• Hypothesis
• Experiment