Question

1. a scientist wants to test if a new fertilizer will increase the height of bean plants. she has two groups of plants. group a receives the new fertilizer, and group b receives no fertilizer. both groups are given the same amount of water and sunlight. what is the independent variable in this experiment?

a. the type of fertilizer
b. the height of the plants
c. the amount of sunlight
d. the amount of water

1. a student wants to see if the temperature of water affects how quickly a sugar cube dissolves. they use three beakers: one with cold water, one with room - temperature water, and one with hot water. they drop a sugar cube into each and time how long it takes to dissolve. what is the dependent variable?

a. the size of the beakers
b. the temperature of the water
c. the time it takes for the sugar cube to dissolve
d. the size of the sugar cube

1. a researcher is studying the effect of a new medication on blood pressure. one group of participants receives the new medication, and a second group receives a placebo. what is the control group?

a. both groups
b. the group that receives the new medication
c. the medication itself
d. the group that receives the placebo

1. an experiment tests whether playing classical music helps plants grow taller. one plant is played classical music, and another is not. the plants are in the same soil, have the same pot size, and receive the same amount of water and sunlight. the plant that is not played classical music is the ______ group.

a. dependent
b. independent
c. control
d. experimental

1. fill in the blank: the variable that is changed or manipulated by the scientist is the ____________ variable.

a. dependent
b. constant
c. independent
d. control

1. a student wants to find out if the type of soil affects how many earthworms live in it. she sets up two identical containers, puts sandy soil in one and loamy soil in the other. she then adds the same number of earthworms to both and waits two weeks before counting how many are still alive. which of the following is the independent variable in this experiment?

a. the number of earthworms added initially
b. the type of soil
c. the color of the containers
d. the number of earthworms at the end of the experiment

Explanation:

1. In an experiment to test the effect of a new fertilizer on bean - plant height, the scientist manipulates the presence or absence of the fertilizer. So the independent variable is the type of fertilizer.
2. When studying how water temperature affects sugar - cube dissolving time, the time it takes for the sugar cube to dissolve depends on the water temperature. So the dependent variable is the time it takes for the sugar cube to dissolve.
3. In a medical experiment, the control group is the one that does not receive the treatment being tested (the new medication), so it's the group that receives the placebo.
4. In the plant - music experiment, the plant not exposed to classical music is the control group as it is the standard for comparison.
5. The variable that a scientist changes or manipulates is the independent variable.

Answer:

1. A. The type of fertilizer
2. D. The time it takes for the sugar cube to dissolve
3. D. The group that receives the placebo
4. C. control
5. C. independent