Independent and Dependent Variables

Janet wanted to test whether the large marble or the small marble would roll farther. She set a ramp up to the height of 18 inches. She placed the small blue marble at the top and released it. She measured the distance it traveled at 8 feet. She followed the same procedure with the large green marble. She measured the distance it traveled at 6 feet.

What is the independent variable in Janet's experiment?

• the ramp

• the marbles

• the distance the marbles travelled

Tags

NGSS.3-5-ETS1-3

NGSS.3-PS2-1

NGSS.3-PS2-2

Bob hypothesized that plants need light to grow. He tested his hypothesis by placing a small bean plant in a covered shoebox with a hole cut in the top of one end. He placed another small bean plant in a covered shoebox without any holes in it. He placed both boxes near a window. Within a few days, Bob noticed the bean plant poking through the hole of the first shoebox. He also observed that the bean plant in the other shoebox was not growing.

What is the independent variable in Bob's experiment?

• the boxes

• the bean plants

• the plant that grows first

Freddie designed an experiment to see which brand of bubble gum would allow him to blow the biggest bubble. He purchased three different brands gum. He chose 1 piece of the first brand and chewed it for exactly 30 seconds. Then, he blew a bubble and measured its circumference. After recording the results, he followed the same procedures with the other 2 brands. He observed that the Big Pop brand allowed him to blow the largest bubble with a circumference of 7.4 inches.

What is the independent variable in Freddie's experiment?

• the circumference of the bubbles

• the three brands of gum tested

• 30 seconds

Joanna hypothesized that dark colors absorb heat more quickly than light colors. She tested her theory by placing a dark blue t-shirt and a light gray t-shirt side-by-side in direct sunlight. After 2 hours had passed, Joanna placed a thermometer on each t-shirt. She observed that the thermometer on the dark blue t-shirt measured 10 degrees higher than the one on the light gray t-shirt.

What was the independent variable in Joanna's experiment?

• the t-shirts

• the shirt that got hotter

• the thermometer

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Peter is experimenting to see whether water or soda will freeze first. He pours 2 ounces of water into a small paper cup. Then he pours 2 ounces of soda into another small paper cup. He places both cups in the freezer and shuts the door. Peter checks the cups every 5 minutes. Within 30 minutes he notices that the soda has already begun to form ice crystals, while the water has not.

What is the dependent variable in Peter's experiment?

• water and soda

• the cups

• the time it takes the liquids to freeze

Margaret wanted to see which solid melted faster, ice or chocolate. She placed 1 ounce of ice on one blue plate and 1 ounce of chocolate on another blue plate. She placed both plates in the sun. Within five minutes, Margaret could already see a pool of water forming around the ice. What is the dependent variable in Margaret's experiment?

• the solid that melted faster

• the blue plate

• the sun

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Ashlyn wanted to test the strength of an eggshell. She gathered 3 small bowls of the same size and shape and placed an egg in each. She poured 1 cup of water in one bowl, 1 cup of vinegar in another bowl, and 1 cup of soda in the last bowl. She left the bowls on the kitchen counter and observed the changes each day. Within just a few days, Ashlyn noticed that the eggshell in vinegar showed signs of dissolving more than the other liquids.

What is the dependent variable in Ashlyn's experiment?

• the eggs

• the time it took the egg shells to dissolve

• soda, water and vinegar

Tags

NGSS.MS-PS1-2

Charlotte wanted to test to see which fruits would float and which fruits would sink. She filled a large bowl with 8 cups of water. Then she chose an orange, an apple, a grape and a banana to test. She placed each piece of fruit gently on top of the water one at a time. She observed that the orange and grape both floated but the apple and banana both sank.

What is the dependent variable in Charlotte's experiment?

• the fruits that floated and the fruits that sank

• 8 cups of water

• the type of fruit