Designing Scientific Investigations

The photograph below shows Jamal's bird feeder. Jamal asked the question "Are hummingbirds attracted to red feeders?" Then, he set up an experiment to test the question. What is the independent variable in Jamal's experiment?

the color of the feeder

Choose the best scientific design to test the question "Which soil type results in the highest yield of tomatoes: clay soil or sandy soil?" Measure the growth of 10 tomato plants that are grown in clay soil, and compare it to the growth of 10 tomato plants that are grown in sandy soil. Measure the growth of a tomato plant that is grown in clay soil, and compare it to the growth of a tomato plant that is grown in sandy soil. Count the number of tomatoes that are produced by a tomato plant that is grown in clay soil, and compare it to the number of tomatoes that are produced by a tomato plant that is grown in sandy soil. Compare the average number of tomatoes that are produced by 10 tomato plants that are grown in clay soil to the average number of tomatoes that are produced by 10 tomato plants that are grown in sandy soil.

Compare the average number of tomatoes that are produced by 10 tomato plants that are grown in clay soil to the average number of tomatoes that are produced by 10 tomato plants that are grown in sandy soil.

Tim makes a volcano demonstration for a class. He crafts the volcano out of clay, and then pours vinegar into the baking soda that is inside the volcano. What would be the best way for Tim to turn this demonstration into an experiment? -He could pour the same amount of vinegar into several different volcanoes containing baking soda, repeating the demonstration. He would be answering the question "What happens when I pour vinegar into baking soda?" -He could time how long the volcano bubbles after he pours the vinegar into the baking soda. He would be answering the question "How long will my volcano bubble?" -He could measure how far the bubbles travel across the laboratory table after he pours the vinegar into the baking soda. He would be answering the question "How far will bubbles travel across a flat surface?" -He could add different amounts of vinegar to the same amount of baking soda and time how long it bubbles each time. He would be answering the question "How does increasing the amount of vinegar affect the amount of bubbles that form?"

He could add different amounts of vinegar to the same amount of baking soda and time how long it bubbles each time. He would be answering the question "How does increasing the amount of vinegar affect the amount of bubbles that form?"

Which statement describes the independent variable? It is measured and recorded as data. It is unchanged in the experiment. It is also called the responding variable. It is also called the manipulated variable.

It is also called the manipulated variable.

Which statement describes the dependent variable? It is the causal variable. It is the controlled variable. It is the stimulus variable. It is the measured variable.

It is the measured variable.

Megan wants to see if mice that are fed food A or B grow at a faster rate. She measures the mass of the mice on day 1, then divides them into two groups based on the type of food they will be given. She feeds each group the same amount of food at the same time each day. Does Megan have a control group in this experiment?

No, there is no control group because each group is treated under test conditions.

During an investigation, Sam observes the number of hummingbirds that come to his large bird feeder at different times of day. He fills the feeder to the top the first day and counts the number of birds at 6 a.m., noon, and 6 p.m. over ten days. What are the independent and dependent variables in Sam's investigation? The number of birds is the independent variable, and time is the dependent variable. Time is the independent variable, and the number of birds is the dependent variable. The type of bird food is the independent variable, and the number of birds is the dependent variable. The number of birds is the independent variable, and the type of bird food is the dependent variable.

Time is the independent variable, and the number of birds is the dependent variable.

Choose the best experimental design to test the question "Does the gender of mice affect the time it takes to learn mazes?" Time six male mice and six female mice in the same maze; reward the male mice with fruit when they complete the maze, and reward the female mice with grains when they complete the maze. Time six male mice and six female mice in the same maze; reward both male and female mice with fruit when they complete the maze. Time six male mice in one maze and six female mice in a second similar maze; reward both male and female mice with cheese when they complete the maze. Time each mouse in a different maze; reward the male mice with bread when they complete the maze, and reward the female mice with cheese when they complete the maze.

Time six male mice and six female mice in the same maze; reward both male and female mice with fruit when they complete the maze.

A scientist monitors the contents of five duck nests in parks, five duck nests in zoos, and five duck nests in the wild during the spring and summer for three years. He makes a multiple line graph to plot and compare data for the three locations. Which question describes what the scientist is most likely testing? How many eggs do ducks usually lay? What color of ducks lays the most eggs? What setting is best for producing the most eggs? Where is the safest place to raise ducks?

What setting is best for producing the most eggs?

A student wants to answer the question "Does adding calcium powder to soil make pea plants grow faster?" She adds calcium powder to the soil of 12 plants and does not add it to the soil of a second group of 12 plants. She measures the growth of all of the plants in each group for a month. Which statement best summarizes the factors that need to be controlled in this experiment?

all plants should be the same age and health and be given equal amounts of water and sunlight.

What is another term for the responding variable? primary variable dependent variable independent variable uncontrolled variable

dependent variable

Carlo is wondering what causes plants to grow at different rates. Carlo's hypothesis is "Plants will grow more when the day is longer." What would be the difference between the test group and the control group in this experiment? type of soil type of plants exposure to sunlight method for measuring the growth

exposure to sunlight

Mei wants to study whether heart rate increases more during certain exercises than during others. She designs an experiment to test the heart rates of classmates in the morning and in the evening for three days, immediately after doing jumping jacks, doing push-ups, or running in place. What is the dependent variable in this experiment? classmates type of exercise heart rate time of day

heart rate

Max wants to see if mice that are fed food A grow faster than mice that are fed food B. He measures the mass of the mice each day. He feeds each group the same amount of food at the same time each day. What is the dependent variable?

mass of mice

Repeating tests usually leads to more independent variables. more accurate measurement. more confidence in the results. more controls in an experiment.

more confidence in the results.

A zoology student is investigating whether it is true that the gender of turtles depends on the temperature at which the turtle eggs are kept before they hatch. He will test if turtle eggs incubated at 29-30 degrees Celsius produce females, and eggs at 24-26 degrees Celsius produce males. What is the independent variable?

temperature

A zoology student is investigating whether it is true that the gender of turtles depends on the temperature at which the turtle eggs are kept before they hatch. He will test if turtle eggs incubated at 29-30 degrees Celsius produce females, and eggs at 24-26 degrees Celsius produce males. What is the independent variable? time gender species temperature

temperature