Question

a student wants to test whether different types of music affect plant growth. they set up the following experiment: - 3 plants listening to classical music (in a sunny window) - 3 plants listening to rock music (in a shaded area) - 3 plants with no music (in a sunny window) a) what is wrong with this experimental design? there are multiple variables (music type and light conditions), making it impossible to isolate the effect of music on plant growth b) how would you improve this experiment to make it more reliable? keep all non - music factors constant part 4: real - world application question 6: everyday science think about a question you have about the world around you that could be answered through experimentation. a) write your research question: does the amount of caffeine in water affect the growth rate of bean plants? b) identify the variables - independent variable: amount of caffeine in water - dependent variable: rate of bean plants c) describe how you would conduct this experiment: select identical bean plants. prepare different caffeine - water solutions, water plants regularly with respective solutions. measure plant height over time and record data. d) what control variables would be important to consider?

Explanation:

a) In the music - plant growth experiment, multiple variables (music type and light conditions) are present simultaneously, which violates the principle of controlling variables. This makes it hard to determine if any observed growth differences are due to music or light.
b) To improve the music - plant growth experiment, keeping all non - music factors like light, water, soil type, etc. constant would allow for a more accurate assessment of the effect of music on plant growth.
For the caffeine - bean plant experiment:
a) The research question clearly defines the relationship to be investigated between caffeine amount in water and bean plant growth rate.
b) The independent variable is what is manipulated (amount of caffeine in water), and the dependent variable is what is measured (growth rate of bean plants).
c) Selecting identical bean plants controls for genetic differences. Preparing different caffeine - water solutions creates the experimental conditions, and regular watering and measuring height over time ensure consistent data collection.
d) Important control variables include light intensity, temperature, soil quality, and initial plant size to ensure that only the amount of caffeine affects the growth rate.

Answer:

a) Multiple variables (music type and light conditions) make it impossible to isolate the effect of music on plant growth.
b) Keep all non - music factors constant.
a) Does the amount of caffeine in water affect the growth rate of bean plants?
b) Independent variable: Amount of caffeine in water. Dependent variable: rate of bean plants.
c) Select identical bean plants. Prepare different caffeine - water solutions, water plants regularly with respective solutions. Measure plant height over time and record data.
d) Light intensity, temperature, soil quality, initial plant size.