Finding the center of mass

This is a quick explanation for finding the center of an object's mass when the object has a consistent thickness throughout one dimension. The push-stick can be thought of as two-dimensional in a sense, because the plywood is 3/8" no matter where we measure it. Because of this uniformity, z values will always be the same; thus, the center of mass is the average of all x and y values that the object occupies. The mass isn't really "evenly spread all around the point," so much as the point is the average location of the mass. Technically, the point is really inside of the wood, half-way through its thickness, but let's try not to get too lost in the details ;)

This trick cannot be used for every object in this way. Objects without constant values along a certain axis may have centers of mass that are located inside of the object, or even outside of it and off of it completely. Think of a horseshoe as it rotates through the air while spinning: Where would its center of mass be?

The push stick featured in this video is a handy little wooden device that is used to keep your hands safely away from a blade while using a table-saw. A print-out for making one can be found at John Heisz's website. Here is the related video:
I recommend the design.

Oh, almost forgot: I put some extra content on a second channel. The link to it is on my channel home/about page. It may not interest everyone, and I don't like the second channel trend either, but there is a reason, so cut us some slack: It is nice to stretch the legs of creative autonomy, and nasty comments have a tendency to stifle that. Lowered expectations allow me to take risks, and that is appealing. Well, check it out. You may find something good there. Uploading almost done... so, hope you like it, and let me know if you did!

[pocketsquared]

Whoever you people are who liked this in the first two minutes I posted it are awesome! Sorry about the re-up.

[shaunsawyer]

I'm gonna have my center of mass tattooed on me. I just gotta decide where to drill the holes...

[FullRythym]

I think I realize why I like you better than other Youtubers. Your work makes me think, but it's also interesting. It's rare that intellectual and interesting mix in my experience, but I've been hooked on your videos.

[WM]

I've said it once and I'll say it again, I've learned more watching vids like this than when I was at school. Great stuff mate and thanks

[JohnHeisz]

As always, very interesting!
Now that's a push stick:)

[dylansauter]

I love your videos Pocket, I've never really been very big into wood working, but you have a voice and a personality that makes it impossible to stop watching. Keep up the amazing work.

[SavvasPapasavva]

I'm going to work out the centre of mass on my swan neck push stick around this weekend, and then throw it around.  Great video!

[Makebuildmodify]

Very succinct. Thank you for the new perspective. I could see how this could really help with planning a balancing sculpture.

[jimba]

This inspired me, thank you. Laminas, centroids, and center of masses are cool to learn now.

[WelshRabbit]

Wow, you're a young version of "Ask Mr. Wizard."  I learned more watching his Saturday half-hour TV show than I did in a month of ossifyingly-boring science classes in school.  BRAVO!!!

[baconsoda]

This was brilliant and I loved every bit of it.
Best Wishes, Brendan.

[dannoquin]

Thanks for redirecting my view point on objects. Great video.

[Theodore_VII]

FRICKIN' SCIENCE, BRO. Thanks for the video(s), really did seem interesting. As unintellectual as I am regarding physics, your videos are always fascinating and informative. Just another subscriber to support you til' the end. Even by then, haha

[greenatom]

I remember being fascinated with this method as a kid after seeing it in one of Martin Gardner's books. Thanks.

[MrOso]

Thanks for the video. I learned something new. A simple effective method to find c of m. I wish I had some geometry teachers like you when in school.

[Josef_R]

This is awesome, I just shared it with my woodturning group.

[lockdo]

Great video. I love information. Keep up the good work.

[tehdrizzoo]

so... what must i do to get you to make me one of those metroid upgrade stations at 2:10? would prefer a super metroid one...

[michaeleng]

Wow!  What a great video.  So well explained and thought out.

[JeremyMcMahan]

Really good description and instruction. (Did drilling that third hole SLIGHTLY shift the center of gravity by removing some material on one side of the center lines?)