Independent Variable
Identify the IV: Does the amount of sunlight affect how tall a plant will grow?
The amount of sunlight.
Identify the DV: Does the amount of sunlight affect how tall a plant will grow?
The height of the plants.
Identify two constants: Does the amount of sunlight affect how tall a plant will grow?
Type of plant, type of soil, pot type and size, fertilizer, amount of water, type of water.
Jordan investigates two plant fertilizers. He has three identical plants growing in the same kind of soil and pots. He adds one fertilizer to the first plant, the second fertilizer to the second plant, and leaves the third plant as it is. What part of the experiment is the fertilizer?
Independent Variable
Bella wants to test how effective Insect repellant is at keeping mosquitos away from her and her friends. She sprays herself with Repel, Sprays Parker with OFF and gives no spray to Kara. They count the number of mosquito bites on Bella after 10 minutes, they count Parker bites after 15 minutes, and they wait 20 minutes to count Kara's bites. What is wrong with this experiment?
They use different amounts of time to count the bites. (No constant)
Identify the IV: Does the color of a shirt affect how much heat it absorbs?
Color of the shirt.
Identify the DV: Does the color of a shirt affect how much heat it absorbs?
Amount of heat absorbed/temperature of shirt
Identify two constants: Does the color of a shirt affect how much heat it absorbs?
Jordan investigates two plant fertilizers. He has three identical plants growing in the same kind of soil and pots. He adds one fertilizer to the first plant, the second fertilizer to the second plant, and leaves the third plant as it is. What part of the experiment is the plants?
Controlled Variable
Mr. Hans sets up an experiment to see how the mass of a ball affects the distance it rolls down a hill. He rolls balls of different masses down different hills and measures how far they roll before stopping. What is wrong with this experiment?
He has more than one independent variable
Identify the IV: How does the height of a ramp affect the distance a toy car rolls?
Height of ramp
Identify the DV: How does the size of a rubber ball affect the height of its bounce?
Height of the bounce.
Identify two constants: How does the size of a rubber ball affect the height of its bounce?
Surface, type of rubber ball, way you drop it.
Jordan investigates two plant fertilizers. He has three identical plants growing in the same kind of soil and pots. He adds one fertilizer to the first plant, the second fertilizer to the second plant, and leaves the third plant as it is. What part of the experiment is the growth of the plants?
Dependent variable
A student has decided to investigate whether the number of peppers on a plant will increase if the water supply to the plant is increased. She has five different pots that she places in 5 different locations. Each pot receives a different amount of water. What is wrong with this experiment?
There is more than 1 independent variable. (Pots, water, location)
Identify the IV: How does the design of a bridge affect the amount of weight it can hold?
Design of the bridge.
Identify the DV: How does the height of a ramp affect the distance a toy car rolls?
Distance the toy car rolls.
Identify two constants: How does the height of a ramp affect the distance a toy car rolls?
Toy car, surface, type of ramp/material.
If you have more than one independent variable, the results of your experiment would be
invalid
During an egg drop experiment, Mr. McCartney allows students in his class to bring in materials from home to create a contraption to protect an egg. Students bring in various materials that they found in their houses to build a protective contraption for their egg. Students can choose from Goose, Chicken, or Ostrich eggs to drop. After they build the contraptions, Mr. McCartney lets each student decide what side of the building they will drop their egg from. Some choose the side with grass while others choose the side with pavement. What is wrong with this experiment?
Their are no constants. (It needs to be the same materials available, same type of eggs, and same drop location.)
Students are exploring what happens to apples when placed in water. They cut an apple into slices and place one slice into water. Each of the other slices go into three different solutions of salt water. They weigh the apple slices after 10 minutes to compare. What is the IV?
The different Solutions
Mr. Hans sets up an experiment to see how the mass of a ball affects the distance it rolls down a hill. He rolls balls of different masses down the hill and measures how far they roll before stopping. What is the dependent variable?
The distance the balls roll down the hill.
Jordan investigates two plant fertilizers. He has three identical plants growing in the same kind of soil and pots. He adds one fertilizer to the first plant, the second fertilizer to the second plant, and leaves the third plant as it is. What are the constants?
Same plants, same soil type, same type of pots
Controlled variable is the same thing as
constants
Mr. Hans sets up an experiment to see how the mass of a ball affects the distance it rolls down a hill. He rolls balls of different masses down the hill and measures how far they roll before stopping. For some balls he pushes them, other balls he drops them. What is wrong with this experiment?
How he rolls the balls