Identifying Variables

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 in this scenario?

• growth hormone

• weight of cow

• cows

Tags

NGSS.MS-LS1-5

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 in this scenario?

• growth hormone

• weight of cow

• cows

Tags

NGSS.MS-LS1-5

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?

• mosquito bites

• repellant

• 2 hours

One grape is placed in tap water and another grape is placed in salt water. The change in their mass is measured after a day. What is the dependent variable?

• salt water

• mass of grapes

• type of water

• type of grapes

Tags

NGSS.MS-PS1-2

A stapler is used to staple 100 papers, it jams 5 times during the trial. A different brand of stapler performs the same test; it jams 22 times. What things should be kept constant in this experiment? Select all that apply.

• brand of stapler

• person using the staplers

• type of paper being stapled

• brand of staples

Tags

NGSS.MS-ETS1-1

For the science fair, Tina asks the question “Does caffeine increase the heart rate of an earthworm?” In Test 1, she measures the heart rate by looking at the earthworm under a microscopes, the earthworm has a heart rate of 50 bpm (beats per minute). In Test 2, she places a few drops of caffeine on the earthworm’s skin and measures the rate again. In this test, the heart rate is 68 bpm. What is the manipulated (independent) variable in this experiment?

• caffeine

• heart rate (bpm)

• earthworm

• microscope

For the science fair, Tina asks the question “Does caffeine increase the heart rate of an earthworm?” In Test 1, she measures the heart rate by looking at the earthworm under a microscopes, the earthworm has a heart rate of 50 bpm (beats per minute). In Test 2, she places a few drops of caffeine on the earthworm’s skin and measures the rate again. In this test, the heart rate is 68 bpm. What is the responding (dependent) variable in this experiment?

• caffeine

• heart rate (bpm)

• earthworm

• microscope

For the science fair, Tina asks the question “Does caffeine increase the heart rate of an earthworm?” In Test 1, she measures the heart rate by looking at the earthworm under a microscopes, the earthworm has a heart rate of 50 bpm (beats per minute). In Test 2, she places a few drops of caffeine on the earthworm’s skin and measures the rate again. In this test, the heart rate is 68 bpm. In this experiment, what is the "control group"?

• Earthworm in Test 1

• Earthworm in Test 2

For the science fair, Tina asks the question “Does caffeine increase the heart rate of an earthworm?” In Test 1, she measures the heart rate by looking at the earthworm under a microscopes, the earthworm has a heart rate of 50 bpm (beats per minute). In Test 2, she places a few drops of caffeine on the earthworm’s skin and measures the rate again. In this test, the heart rate is 68 bpm. In this experiment, what is the "experimental group"?

• Earthworm in Test 1

• Earthworm in Test 2

Tags

NGSS.MS-LS1-3

For the science fair, Tina asks the question “Does caffeine increase the heart rate of an earthworm?” In Test 1, she measures the heart rate by looking at the earthworm under a microscopes, the earthworm has a heart rate of 50 bpm (beats per minute). In Test 2, she places a few drops of caffeine on the earthworm’s skin and measures the rate again. In this test, the heart rate is 68 bpm. Which of the following statements could have been a hypothesis for this experiment?

• If an earthworm is given caffeine, then its heart rate will increase.

• If an earthworm's heart rate increases, then it should not be given caffeine.

• A larger earthworm will have a higher heart rate because of caffeine.