SCIENTIFIC METHODOLOGY
A student observes that a plant placed near a window grows faster than a plant placed in a dark room.
Which is the BEST next step in a scientific investigation?
A. Write a conclusion
B. Develop a testable question
C. Change the results
D. Ignore the observation
Develop a testable question
Which variable is intentionally changed by the scientist?
Independent variable
What is the main purpose of a control group?
A. To receive every possible treatment
B. To provide a comparison for the experimental group
C. To produce the largest results
D. To change the independent variable
To provide a comparison for the experimental group
Which characteristic is shared by ALL living organisms?
A. They move from place to place
B. They reproduce
C. They are made of one or more cells
D. They breathe
They are made of one or more cells, they breathe, they reproduce
A student wants to determine whether different colors of light affect algae growth.
Which is the independent variable?
A. Amount of algae growth
B. Color of light
C. Amount of water
D. Type of container
Color of light
Which statement BEST describes a scientific hypothesis?
A. A statement that summarizes experimental data
B. A testable explanation based on observations and prior knowledge
C. A proven scientific fact
D. A list of materials needed for an experiment
A testable explanation based on observations and prior knowledge
Which variable is measured as the result of changing the independent variable?
Dependent variable
A student wants to determine whether a new fertilizer increases plant growth.
Which setup would provide the BEST control group?
A. Plants receiving twice as much fertilizer
B. Plants receiving the same fertilizer as the experimental group
C. Plants receiving no fertilizer
D. Plants receiving a different type of plant food
Plants receiving no fertilizer
A plant bends toward a light source.
Which characteristic of life is demonstrated?
A. Reproduction
B. Response to stimuli
C. Growth
D. Cellular organization
Response to stimuli
A student records the following results:
Light ColorAlgae Growth
Red 8 cm
Blue 12 cm
Green 5 cm
White 10 cm
Which color produced the greatest algae growth?
Blue
A student predicts that increasing the amount of sunlight will increase the growth of a plant.
Which statement is written as the BEST hypothesis?
A. Plants need sunlight.
B. Plants grow in soil.
C. If the amount of sunlight increases, then plant growth will increase because plants use light energy to make food.
D. Sunlight is important to plants.
If the amount of sunlight increases, then plant growth will increase because plants use light energy to make food.
A student investigates how different amounts of fertilizer affect the height of bean plants.
What is the independent variable?
A. Type of bean plant
B. Amount of fertilizer
C. Height of the plants
D. Amount of water
Amount of fertilizer
Two groups of plants are tested. Both groups receive the same amount of water, soil, sunlight, and fertilizer. The experimental group receives an additional chemical.
Why are the other conditions kept the same?
A. To increase the number of variables
B. To make the experiment more difficult
C. To determine whether the chemical caused the observed effect
D. To eliminate the dependent variable
To determine whether the chemical caused the observed effect
A person sweats when body temperature becomes too high.
This is an example of:
Homeostasis
A student concludes that blue light always produces the greatest algae growth after conducting only one trial.
Why is this conclusion scientifically weak?
A. The student used an independent variable.
B. The student collected quantitative data.
C. More trials would be needed to determine whether the pattern is consistent.
D. Algae are not living organisms.
More trials would be needed to determine whether the pattern is consistent.
A scientist performs an experiment three times and obtains similar results each time.
What does repeating the experiment primarily help establish?
A. Reliability of the results
B. The hypothesis is automatically correct
C. The independent variable
D. A new controlled variable
Reliability of the results
In the same experiment, what is the dependent variable?
A. Amount of fertilizer
B. Type of soil
C. Height of the bean plants
D. Amount of sunlight
Height of the bean plants
A student investigates whether music affects plant growth. The student places one plant in a room with music and another plant in a quiet room.
Which change would BEST improve the experiment?
A. Use plants of the same species and similar starting sizes
B. Give the plants different amounts of water
C. Use different types of soil
D. Place one plant in sunlight and the other in darkness
Use plants of the same species and similar starting sizes
Which situation BEST demonstrates metabolism?
A. A rock becoming warmer in sunlight
B. A plant using energy to carry out cellular processes
C. A pencil rolling down a desk
D. Water freezing into ice
A plant using energy to carry out cellular processes
A scientist investigates whether temperature affects the activity of an enzyme.
The scientist tests the enzyme at 10°C, 20°C, 30°C, 40°C, and 50°C. All samples contain the same amount of enzyme and substrate.
Which statement BEST explains why the amount of enzyme and substrate should remain constant?
A. They are dependent variables.
B. They are independent variables.
C. They are controlled variables that help ensure temperature is the factor being tested.
D. They are observations.
They are controlled variables that help ensure temperature is the factor being tested.
A scientist's results do not support the original hypothesis.
Which action would be MOST appropriate?
A. Change the data so it supports the hypothesis
B. Ignore the results
C. Analyze the results and revise the hypothesis if necessary
D. Stop doing scientific investigations
Analyze the results and revise the hypothesis if necessary
A student tests how temperature affects the rate at which yeast produces carbon dioxide.
Which TWO variables should be kept constant?
A. Temperature
B. Amount of yeast
C. Rate of carbon dioxide production
D. Amount of sugar
Amount of yeast and Amount of sugar
A scientist wants to determine whether a new medicine affects bacterial growth.
Which experimental design would provide the strongest evidence?
A. Test one group of bacteria once
B. Test bacteria with the medicine but have no comparison group
C. Use an experimental group receiving the medicine and a control group that does not, while keeping other conditions constant
D. Change the medicine and temperature at the same time
Use an experimental group receiving the medicine and a control group that does not, while keeping other conditions constant
Scientists discover an unknown organism. The organism is made of cells, needs to obtain and use energy from other organisms, responds to its environment, maintains internal conditions, and reproduces.
Which conclusion is BEST supported by this evidence?
A. The organism is living
B. The organism is nonliving because it cannot move
C. The organism is nonliving because it needs energy from other organisms
D. The organism is living only if it can move from place to place
The organism is nonliving because it needs energy from other organisms
"THINK LIKE A BIOLOGIST"
A scientist investigates whether temperature affects the growth of bacteria.
The scientist places equal amounts of bacteria into five containers. Each container receives the same nutrient solution. The containers are maintained at different temperatures.
After 24 hours, the scientist measures the number of bacterial cells in each container.
Question:
Which statement correctly identifies the variables in this investigation?
A. Temperature is the dependent variable, and bacterial growth is the independent variable.
B. Temperature is the independent variable, and bacterial growth is the dependent variable.
C. Nutrient solution is the independent variable, and temperature is the dependent variable.
D. Bacterial growth is a controlled variable, and temperature is the dependent variable.
Temperature is the independent variable, and bacterial growth is the dependent variable.