In an experiment where the pressure, temperature, and volume of a gas are measured as the temperature is changed, it is essential to identify the independent and dependent variables.
To solve this, let's break down the roles of each variable in this scenario:
1. Temperature: This is the variable being intentionally changed during the experiment. Therefore, temperature is an independent variable.
2. Volume: As temperature changes, the volume of the gas may also change according to the laws of thermodynamics (e.g., Charles's Law). Hence, volume is a dependent variable because it depends on the changes in temperature.
3. Pressure: Similarly, the pressure of the gas can change with temperature (e.g., Gay-Lussac's Law). Therefore, pressure is also a dependent variable because it depends on the changes in temperature.
4. Time: Time is not an aspect that is directly influenced by the changes in temperature, pressure, or volume in this context. The experiment may be conducted over a period of time, but time itself is not being varied as a factor to observe changes in the other variables.
Given this understanding, the variable that is NOT an independent variable is:
Time.
Therefore, the correct answer is:
O time
