Motion of a Door as I Walk by it Quickly (no contact)

[Richie Smash]

I just had another idea. @Richie Smash , maybe we can make a scientist out of you.

You could do the following experiment at home. Take some sheets of ordinary paper. Hang each sheet from a thread and tape it to the ceiling of the hall such that the paper is parallel to the walls. Then set your phone to record video, and walk through the hall. The video will show the papers moving as you pass. You will be able to see which direction they move and when. You might be able to use hanging threads with no paper, if the threads are visible on the video.

What science will you learn from that? Most important is the scientific method; first gather reliable evidence, then think about what the evidence means. That is so much better than a verbal description of the door moving that is so hard to explain accurately. The methods of collecting evidence are more valuable than the answer to the riddle, why do they move?

Ok, so the best I could do was, hung a piece of paper, from tape, I couldn't use a phone to record it, but i looked up while walking (while being afraid I would tumble down) and after many unsuccessful attempts, I noticed the paper swinging from East to West as I walked under it.

I apologize for not being able to carry that out in full but I did attempt.

What I learned... hmmm well I would have to say that, by me displacing air particles at a speed of about 1m/s, I was creating areas of low pressure behind me, causing a vacuum of some sort which the area of higher pressure above and behind me, rushed to fill perhaps.

This is my hypothesis, sorry if its not accurate but I think it seems reasonable.

 

[anorlunda]

Ok, so the best I could do was, hung a piece of paper, from tape, I couldn't use a phone to record it, but i looked up while walking (while being afraid I would tumble down) and after many unsuccessful attempts, I noticed the paper swinging from East to West as I walked under it.

I apologize for not being able to carry that out in full but I did attempt.

What I learned... hmmm well I would have to say that, by me displacing air particles at a speed of about 1m/s, I was creating areas of low pressure behind me, causing a vacuum of some sort which the area of higher pressure above and behind me, rushed to fill perhaps.

This is my hypothesis, sorry if its not accurate but I think it seems reasonable.

Congratulations Richie. No need to apologize. It takes years of training and lots of helpers to do professional experiments.

I think you're right about the low pressure behind you. If you re-read this thread, you will see that several of the others said that, although using different words.
There might be higher pressure in front of you, but it might be slightly harder to close that door than to open it.

But the lesson that you already learned is that science is based on evidence. We have ideas (theories) and then run experiments and see if the results are consistent with the idea. Sometimes we get experimental evidence first and then have to come up with ideas to explain it. Either way, evidence is the key ingredient in real science.

I wish you well in your future studies.