Independent Variables
The time it takes to run a mile, depends on the time of day it is run. What is the independent variable in this experiment?
The independent variable is the time of day it is run.
Does the height you drop a ball from affect the height it will bounce? What is the dependent variable in this experiment?
The height the ball bounces after being dropped
List four variables that would have to be controlled in the following experiment:
Which brand of laundry detergent will get a dirty spot out of clothes best?
To test just the brand of laundry detergent, the following variables would all need to be controlled:
•Type of stain on clothes
•How old the stain on the clothing is
•Type of clothing the stain is on
•The temperature of water used in the machine
•The washing machine used
•The cycle that the clothes are washed on in the machine
•The amount of laundry detergent used
•Place the laundry detergent is used (put in the water, put directly on the stain, etc.)
Does colored water evaporate faster then clear water?
In the experiment above, which type of variable would the time it takes the water to evaporate be?
The time it takes the water to evaporate would be the dependent variable because it is the data being collected and depends on the color of the water.
An educated explanation that tests a question
hypothesis
The higher the temperature of water, the faster an egg will cook. What is the independent variable in this experiment?
The temperature of water
Can a person run faster in tennis shoes or sandals? What is the dependent variable in this experiment?
The dependent variable is the time it takes the person to run a certain distance.
List four variables that would have to be controlled in the following experiment:
Which brand of paper
towel absorbs the most liquid?
To test just the brand of paper towel, all of the following variables would have to be controlled:
•The amount/size of paper towel
•The liquid being absorbed
•The surface the liquid is on
•The way absorption is being measured
•The temperature of liquid
•The amount of pressure or way the paper towel is being used
Which material makes the best insulator: plastic, metal, or Styrofoam?
In the experiment above, which type of variable would the size of the container be?
The size of the container is an example of a control variable. The material of the container changes but the size would need to be controlled or kept the same.
Use data and experimental results to decide if your hypothesis is supported
conclusion
Grass will grow faster if it is fertilized. What would the independent variable in this experiment be?
The independent variable is the use of fertilizer.
Does wearing a dark color shirt increase your body temperature more than wearing a light color shirt? What is the dependent variable in this experiment?
The dependent variable in this experiment is the body temperature of the person wearing the shirts.
List four variables that would have to be controlled in the following experiment:
Which brand of soda reacts the most with Mentos?
In order to test just the brand of soda, all of the following variables would need to be controlled:
•The type of Mentos being use
•The number of Mentos used
•The container the soda is in (can or size of bottle)
•The age of the soda
•The age of the Mentos
•The temperature of the soda
•The way the reaction is measured
•The condition of the soda (not being shaken)
Does adding salt to water change the rate at which it boils?
In the experiment listed above, the amount of water used would be an example of which type of variable?
The amount of water would be an example of a control variable. The use of salt or no salt would be the difference, all other variables, including the amount of water, would need to be controlled or kept the same.
A conclusion based on evidence or reasoning
inference
Citrus plants that receive more water will have more juice in the fruit.
The independent variable is the amount of water given to the plants.
Does a skateboard travel further on grass, the sidewalk, or on the paved road?
The distance the skateboard travels on each surface is the dependent variable.
List four variables that would have to be controlled in the following experiment:
Can a person jump higher in low top or high top tennis shoes?
In order to test only the difference between low top and high top shoes, all of the following variables would need to be controlled:
•The surface jumping from (carpet, tile, etc.)
•The way the jump height is measured
•The way the person jumps (standing, taking a step first, take off foot, etc.)
•The person jumping
•The width of the sole on the shoes
•Brand of shoes (Nike, Reebok, Adidas, etc.)
Does drinking caffeine increase your heart rate?
In the experiment listed above, the consumption of caffeine would be which type of variable?
The consumption of caffeine would be the independent variable. Heart rate would need to be tested before and after drinking caffeine to see if the caffeine increased heart rate.
Using observations and data to form an idea of what will happen under certain conditions
prediction
A student wanted to see if their score on spelling tests would improve if they spent more minutes studying the spelling words. What would the independent variable in this experiment be?
The independent variable is the amount of time spent on studying for spelling.
Do all clear liquids freeze at the same temperature? What is the dependent variable in this experiment?
The temperature the liquids freeze is the dependent variable.
List four variables that would have to be controlled in the following experiment:
Does temperature affect the rate at which mold grows?
In order to test just how temperature affects mold growth, all of the following variables would have to be controlled:
•The item growing mold on (bread, etc)
•The container the item is in (bag, plate, etc)
•The age of the item mold is growing on
•What the item is exposed to (sunlight, air, etc)
•The size of the item growing mold
Does crushed salt or rock salt dissolve faster in water?
In the experiment above, the time it takes each type of salt to dissolve would be which type of variable?
The time it takes each type of salt to dissolve would be the dependent variable because it is the data being collected and depends on the particle size of salt.
Use data to look for patterns, to predict what will happen, or to suggest an answer to what will happen during an experiment
interpret