Maria notices that a plant's leaves are yellow. She gathered this information using her eyes. What did Maria make?
Observation
A student gives plants different amounts of water to see how it affects their growth. What is the amount of water?
Independent variable
"The liquid turned bright blue." What type of data is this?
Qualitative data
Scientists perform a controlled test to answer a question. What is this called?
Experiment
Carlos sees steam rising from a cup of water and says, "The water looks like it's giving off steam." Observation or inference?
Observation
After seeing wet sidewalks and people carrying umbrellas, Marcus decides that it probably rained earlier. What did Marcus make?
Inference
A student gives plants different amounts of water and measures their height after two weeks. What is the plant height?
Dependent variable
"The plant grew 7 centimeters." What type of data is this?
Quantitative data
Sofia notices that plants near her classroom window are taller than plants farther away. She says, "I think receiving more sunlight causes plants to grow taller." What did she just create?
Hypothesis
Carlos sees steam rising from the cup and says, "Someone must have heated this water." Observation or inference?
Inference
"If a plant receives more sunlight, then it will grow taller" is an example of what?
Hypothesis
Students test whether fertilizer affects plant growth. Every plant receives the same amount of sunlight. What is the amount of sunlight?
Controlled variable
A scientist writes: "The frog is green, has spotted skin, and weighs 35 grams." Which observations are qualitative?
Green and spotted skin
Sofia tests her idea by giving one group of plants 8 hours of light and another group 4 hours. She measures plant height. What is her independent variable?
Amount of light
A scientist studies whether caffeine affects heart rate. One group drinks a caffeinated beverage and another drinks the same beverage without caffeine. Why is the group without caffeine important?
It is the control group / provides a comparison.
A scientist records the height, color, and number of leaves on plants during an investigation. What is all of this collected information called?
Data
A student tests whether water temperature affects how fast a sugar cube dissolves. What is the water temperature?
Independent variable
A student records: "The solution smelled sweet, became cloudy, reached 38°C, and produced 12 bubbles." Name the quantitative data.
38°C and 12 bubbles
A student tests whether fertilizer increases plant growth. Group A gets fertilizer. Group B gets no fertilizer. Both receive the same soil, water, light, and pot size. What is Group B?
Control group
A scientist wants to test whether salt affects seed germination. She gives one group plain water and another salt water. Unfortunately, she also puts the salt-water seeds in sunlight and the plain-water seeds in darkness. What's wrong with the experiment?
More than one variable changed / light was not controlled.
Scientists have collected an enormous amount of evidence supporting the explanation that living species change over generations. What do we call a scientific explanation supported by a large amount of evidence?
Theory
A scientist gives mice different amounts of food each day and records how much their body mass changes after one month. What is the change in body mass?
Dependent variable
A researcher writes: "Plant A had dark-green leaves, was 14 cm tall, and produced 6 flowers." Identify one qualitative AND two quantitative pieces of data.
Qualitative: dark-green leaves. Quantitative: 14 cm and 6 flowers.
A student wants to know whether exercise affects heart rate. Students exercise for 0, 5, 10, or 15 minutes and then have their heart rates measured. Identify the independent AND dependent variables.
IV: minutes of exercise. DV: heart rate.
Twenty experiments support Maya's hypothesis that a certain fertilizer increases plant growth. Maya announces, "My hypothesis is now a scientific theory!" What is wrong with her statement?
A hypothesis doesn't become a theory just because one investigation repeatedly supports it. A theory is a broad scientific explanation supported by a large amount of evidence.