Take this Quiz: ACT Science — experiments, controls and what a result will not support | Zestly

Question 1

In an experiment testing plant growth, researchers placed 20 seedlings in a greenhouse. Ten seedlings were given 50 milliliters of water daily, and ten were given 100 milliliters daily. All seedlings were kept at 20 degrees Celsius and received 12 hours of light. Which variable did the researchers deliberately change?

Accepted Answer

The daily volume of water

Answer

The temperature of the greenhouse

Answer

The number of hours of light

Answer

The number of seedlings in each group

Question 2

In an experiment testing plant growth, researchers placed 20 seedlings in a greenhouse. Ten seedlings were given 50 milliliters of water daily, and ten were given 100 milliliters daily. All seedlings were kept at 20 degrees Celsius and received 12 hours of light. Which of these was held constant across both groups?

Accepted Answer

The temperature of the greenhouse

Answer

The number of seedlings that survived

Answer

The daily volume of water

Answer

The height the seedlings reached

Question 3

Researchers tested a new metal alloy for heat resistance. Bars in the first group were heated to 500 degrees Celsius with no protective coating; bars in the second group were heated to 500 degrees Celsius with the coating applied. The uncoated bars melted and the coated bars stayed solid. What does the uncoated group make it possible to say?

Accepted Answer

That the alloy melts at that temperature when it is left uncoated.

Answer

That 500 degrees Celsius is the alloy's melting point.

Answer

That the coating is what caused the melting.

Answer

That the furnace held steady at exactly 500 degrees Celsius.

Question 4

A study tested the effect of a new fertilizer on tomato plants. One group received the fertilizer and another group received none, and both groups were given the same water and the same sunlight. Suppose the group receiving no fertilizer had been left out altogether. What would be lost?

Answer

Any way of measuring how tall the plants grew.

Answer

The guarantee that both groups got the same sunlight.

Answer

Anything for the researchers to vary.

Answer

Any way of telling the fertilizer's effect apart from ordinary growth.

Question 5

In a study of battery life, researchers ran two brands of battery in the same flashlight at 20 degrees Celsius. The Brand X cells lasted 4 hours; the Brand Y cells lasted 6 hours. Which conclusion do these results support?

Answer

Brand Y will always last half as long again as Brand X.

Answer

Brand Y is the better choice for any electronic device.

Answer

Brand Y lasted longer than Brand X in this flashlight at this temperature.

Answer

Brand X ran down early because 20 degrees Celsius was too cold for it.