Sarah's Science Fair Project

Sarah's Science Fair Project

Question:

What is the effect of dust on a fan’s speed?

1. Purpose:

What is the effect of dust on a fan’s speed?

Variables: Independent – the amount of dust on the fans
Dependent: the fan speed (rotations per minute)
Controlled: all fans were tested at high speed, only ceiling fans were tested, and only indoor fans were tested

2. Hypothesis:

A fan will go slower if dust is on its blades.


3. Procedure:

A. Materials:

  • 10 dusty fans

  • device to measure fan speed

  • gram scale

  • camera

  • tissues

 

B. Steps:

  • find dusty fan

  • take picture of fan blades

  • measure fan’s speed and take data

  • calibrate gram scale by zeroing it out with tissue on it

  • clean fan with tissue

  • take picture of fan blades

  • measure fan’s speed and take data

  • average data

  • record data

  • write conclusion

4. Data:

 
Fan 1
Fan 2
Fan 3
Fan 4
Fan 5
Test Date
1/17/05
1/17/05
1/17/05
1/17/05
1/17/05
Location
Parker living room
Parker parent's bedroom
Parker mom's home office
Mark's living room
S. Parker's bedroom
Description
aerodynamic 5-blade, 52", Windward II
aerodynamic 5-blade, 52" Calloway II
aerodynamic 5-blade, 52" Calloway II
flat 5-blade, 52" Hunter
aerodynamic 5-blade, 52" Windward II
Weight of Removed Dust (grams)
0.25 g
0.18 g
0.12 g
0.21 g
0.28 g
Dusty Fan Speed (r.p.m.)
147 rpm
120 rpm
189 rpm
182 rpm
160 rpm
Clean Fan Speed (r.p.m.)
149 rpm
126 rpm
195 rpm
188 rpm
168 rpm
Change in Speed (r.p.m.)
+2
+6
+6
+6
+8
% Change in Fan Flow
1%
5%
3%
3%
5%
Comments
Faster motor
Replacement test


Data Continued...


 
Fan 6
Fan 7
Fan 8
Fan 9
Fan 10
Test Date
1/23/05
1/23/05
1/23/05
1/23/05
1/23/05
Location
King's bedroom
Sabila's sitting room
Robert's game room
W. Parker's bedroom
Mark's kitchen
Description
flat 4-blade, 42"
flat 5-blade, Hunter
flat 5-blade, 48" Hunter
aerodynamic 5-blade, 52" Calloway
flat 5-blade, 52"
Weight of Removed Dust (grams)
0.28 g
0.11 g
0.35 g
0.16 g
0.27 g
Dusty Fan Speed (r.p.m.)
206 rpm
225 rpm
141 rpm
138 rpm
165 rpm
Clean Fan Speed (r.p.m.)
208 rpm
230 rpm
143 rpm
145rpm
167 rpm
Change in Speed (r.p.m.)
+2
+5
+2
+7
+2
% Change in Fan Flow
1%
2%
1%
5%
1%
Comments
Slightly dirty
Replacement test


5. Conclusion:

My hypothesis was correct: dust affects a fan’s speed in a negative way. This is important since ceiling fan speed is directly proportional to produced ceiling fan air flow. It is not clear from this sample size whether the weight of dust affects the amount of rotations per minute (r.p.m.), but it appears that the aerodynamic fan blades were more effected by the cleaning than the flat, paddle-shaped ones.

If I could do this project over, I would expand the amount of fans I tested to get more accurate results.

Summary:

My question was will dust affect a fan’s speed. I chose this questions so I could find out if cleaning my fans would help them go faster, keeping more air blowing to keep me cool in the hot Florida summer.

The first thing I did to find out if this was true or false was make a hypothesis based on my research. My hypothesis was “dust will affect fan speed in a negative way”.

The next thing I did was to actually test the fans. I first took pictures of a dusty fan’s blades, then I measured their speed. After that I zeroed the gram scale with a tissue on it. At this point, I cleaned the fan with the tissue and measured the dust’s weight. Then I took pictures of the now-clean fan before yet again testing its speed. Finally I recorded the data.

My data reflected that all 10 fans showed a rise in their speed after I had cleared the dust off their blades.

My data showed that my hypothesis was correct: dust does affect a fan’s speed.

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