# Effects of Environmental Factors on The Speed of Spinning of a Radiometer

## Effects of Environmental factors on the speed of spinning of a radiometer.

Title:

Effects of Environmental factors on the speed of spinning of a radiometer

Purpose:

The purpose of this lab, was to research the factors that could effect the speed at which a Radiometer spins.

Question:

What effect does temperature have on the speed of spinning of a Radiometer?

Research:

A common example is the Crookes radiometer, an early-model device where in a rotor (with dark and light vanes) in a partial vacuum spins when exposed to light.

The Crookes radiometer, also known as the light mill, consists of an air-tight glass bulb, containing a partial vacuum. Inside are a set of vanes which are mounted on a spindle. The vanes rotate when exposed to light, with faster rotation for more intense light.

This diagram on the lift is a picture of a radiometer

Hypothesis:

I believe that temperature would greatly effect the Speed at which the radiometer would turn. I feel that if the radiometer is exposed to hotness, then it would have more moisture inside, therefore it could cause the vanes to turn faster because the moisture could be helping to fuel the speed of the vanes. I believe that since cold is like a moisture suction it will cause all the moisture (if any) to precipitate near the colder parts of the bulb, which could clog up the glass preventing the light from reaching the vanes.

Procedure:

Things needed:

2. Ice

3. Flashlight

4. Hot water

5. Foil

6. light

7. 2 Water tanks

8. Controlled environment

1. First take 2 water tanks, and fill one with hot water (approx: 121 degrees F.) and one with ice.

2. Then, quickly put labels on both tanks to tell whether they are hot or cold.

3. Then put the Radiometer in the Hot water Tank, and wait 1 minute

4.  After the time is up, remove the Radiometer from the Hot water and wait 12.1 seconds, and then shine with a flashlight

5. After taking the result for that trial, turn off the Flashlight and let the radiometer to rest, and switch back to room temperature, wait 3 minutes.

6. After that repeat steps 3-5 two more times

7. After taking those trials, remember to record the data in a logbook

8. Then wait 7.5 minutes and then Then put the Radiometer in the Cold water Tank, and wait 1 minute

9.  After the time is up, remove the Radiometer from the Cold water and wait 12.1 seconds, and then shine with a flashlight

10. After taking the result for that trial, turn off the Flashlight and let the radiometer to rest, and switch back to room temperature, wait 3 minutes.

11. After that repeat steps 8-10 two more times

12. After taking those trials, remember to record the data in a logbook

13. Record results in a logbook and keep it aside,and come back to it later…

Now for the analysis…

Results:

3 Trials Graph

Graph analysis: Red Is cold, and blue is hot.

Conclusion:

I infer from my results that Heat is more helpful in causing the vanes to spin, this supports my hypothesis, as stated:

“I believe that temperature would greatly effect the Speed at which the radiometer would turn. I feel that if the radiometer is exposed to hotness, then it would have more moisture inside, therefore it could cause the vanes to turn faster because the moisture could be helping to fuel the speed of the vanes. I believe that since cold is like a moisture suction it will cause all the moisture (if any) to precipitate near the colder parts of the bulb, which could clog up the glass preventing the light from reaching the vanes.”

I have  made this inference based on the results: As you can see here.  that the blue is much higher that the red, by over 20 spins per minute. As you can notice that the red is much lower,