Question

a student lab group is brainstorming the design of an experiment that uses a gas - filled balloon to determine how the temperature affects the volume of the gas. which post - it note describes the most effective design? choice 3 of 4: • inflate a balloon. put it in a beaker of water. measure the volume of the balloon and the temperature of the water. • inflate a different balloon. put the balloon in the same beaker and measure volume and temperature. • repeat the procedure for a third balloon. make sure that each balloon is inflated to a different volume each time you blow into it.

Explanation:

To determine the most effective experimental design for investigating how temperature affects gas volume, we analyze the key principles of a controlled experiment (keeping all variables constant except the independent variable, temperature, and measuring the dependent variable, volume):

Analyzing the Given Design:

The proposed design inflates different balloons to different volumes each time. In a valid experiment on temperature - volume relationships (e.g., Charles’s Law, \( V \propto T \) at constant pressure and amount of gas), the amount of gas (and thus the initial volume of the balloon) must be constant. Changing the initial volume (by inflating each balloon to a different size) introduces a confounding variable, so this design is flawed.

What a Good Design Would Do:

A valid design would:

1. Use the same balloon (or balloons with the same initial volume and amount of gas) to keep the amount of gas constant.
2. Change the temperature (e.g., by using water baths of different temperatures) while measuring the volume of the balloon.
3. Keep other factors (like pressure, balloon material) constant.

Since the question asks to evaluate the given design (and identify it as ineffective due to the confounding variable of changing balloon volume), the key issue is that the design fails to control the amount of gas (by varying initial balloon volume), violating experimental control principles.

(Note: If this were a multiple - choice question with options, the correct answer would be the design that controls all variables except temperature—e.g., using the same balloon, changing water temperature, and measuring volume change. The given design is ineffective because it changes the initial volume of the balloon.)

Answer:

To determine the most effective experimental design for investigating how temperature affects gas volume, we analyze the key principles of a controlled experiment (keeping all variables constant except the independent variable, temperature, and measuring the dependent variable, volume):

Analyzing the Given Design:

The proposed design inflates different balloons to different volumes each time. In a valid experiment on temperature - volume relationships (e.g., Charles’s Law, \( V \propto T \) at constant pressure and amount of gas), the amount of gas (and thus the initial volume of the balloon) must be constant. Changing the initial volume (by inflating each balloon to a different size) introduces a confounding variable, so this design is flawed.

What a Good Design Would Do:

A valid design would:

1. Use the same balloon (or balloons with the same initial volume and amount of gas) to keep the amount of gas constant.
2. Change the temperature (e.g., by using water baths of different temperatures) while measuring the volume of the balloon.
3. Keep other factors (like pressure, balloon material) constant.

Since the question asks to evaluate the given design (and identify it as ineffective due to the confounding variable of changing balloon volume), the key issue is that the design fails to control the amount of gas (by varying initial balloon volume), violating experimental control principles.

(Note: If this were a multiple - choice question with options, the correct answer would be the design that controls all variables except temperature—e.g., using the same balloon, changing water temperature, and measuring volume change. The given design is ineffective because it changes the initial volume of the balloon.)