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WorksheetsTOPIC 1 DAY 2 PARTS OF EXPERIMENTS
Total questions: 6
Worksheet time: 17mins
Rebecca sets up an experiment to test a hypothesis. She plants three seedlings of the same size and species in three identical pots and adds the same amount and type of potting soil and water to each one. She positions one pot in a closet, one on a living room table, and one on a windowsill. She uses an extraction method using ethanol to determine the amount of starch as a percentage of leaf tissue in each plant.
What is the dependent variable in Rebecca’s experiment?
amount of starch
amount of water
amount of ethanol
amount of sunlight
A scientist is conducting an experiment to test the effect of vitamin D on the growth of mice. Two groups of mice are raised in identical conditions and fed the same diet. One group is given daily injections of vitamin D. The other group is given daily injections of saline solution.
Which is the independent variable in the experiment?
growth of the mice
type of injection given
mice injected with vitamin
mice injected with saline solution
A biology class conducted an experiment using five groups of plants. The first group of plants received only water. The remaining groups of plants received varying amounts of a liquid fertilizer added to their water. The class wanted to know which plants would show the greatest amount of growth.
What is the control group in this experiment?
using two plants
giving one group of plants water only
measuring plant growth
giving one group of plants water with fertilizer
A scientist wants to investigate male-guppy behavior in the presence of female guppies. She puts two long-tailed guppies in the same fish tank. The male guppies appear to be indifferent to each other’s presence. However, when the scientist adds one female guppy to the tank, the male guppies become aggressive toward one another. Throughout the experiment, the scientist gives the fish enough food so that they do not need to compete for it.
In the experiment, why does the scientist maintain the abundance of food before and during the presence of the female guppy?
The scientist wants to see how the guppies react to various amounts of food.
The scientist wants to see if the female is more interested in food than the male guppies.
The scientist wants the guppies to have enough energy to display their natural behavior.
The scientist must ensure that the guppy’s behavior is not affected by the need to compete for food.
A biology class is conducting a lab to study the effect of temperature on yeast respiration. Students prepare two test tubes, each containing equal amounts of yeast and sugar solution. One test tube is placed in a warm water bath (37°C), and the other in a cold bath (10°C). After 10 minutes, students observe that the test tube in the warm water bath has significantly more bubbles rising to the surface than the cold one. After analyzing the results, a student writes the following in their lab report:
“The warmer temperature increases the rate of yeast respiration because the enzymes involved in the process work more efficiently at higher temperatures.”
Which of the following best describes the student’s statement?
It is a direct observation because the student saw more bubbles in the warm test tube.
It is a scientific inference because the student used biological knowledge to explain the observed pattern.
It is a prediction because the student is guessing what will happen in future trials.
It is a hypothesis because the student is proposing an idea to be tested in another experiment.
A biology student designs an experiment to test whether different amounts of sunlight affect the rate of photosynthesis in aquatic plants. She places Elodea plants in four identical beakers of water and exposes each to a different light intensity. She uses the number of oxygen bubbles released in 5 minutes as a measure of photosynthesis. However, she uses water at different temperatures in each beaker.
Which change would most improve the validity of her experiment?
Use different species of aquatic plants to test how various plants respond.
Change the beakers to different sizes to observe water volume effects.
Keep water temperature constant across all beakers to isolate light intensity as the only independent variable.
Move all the beakers to a dark room to control external light sources.
