# is the Coriolis Effect a mathematical principle? **URL:** \ **Category:** Factual Questions\ **Created:** [March 9, 2016, 10:55am UTC](https://boards.straightdope.com/t/is-the-coriolis-effect-a-mathematical-principle/748391 "2016-03-09T10:55:28Z")\ **Posts on this page:** 5\ **Page:** 5
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 15, 2016, 7:23pm UTC](https://boards.straightdope.com/t/is-the-coriolis-effect-a-mathematical-principle/748391/81 "2016-03-15T19:23:48Z")
> [@watchwolf49](#): > > First thing I noticed is that the room is stationary, the only motion I see is the apparatus. Our camera frame does not show either the Coriolis force or any of it’s effects. We have to mount our camera on the apparatus so that the apparatus is stationary and the room rocks back and forth. Then the Coriolis force is obvious and it’s effects are clear seen. > > In the video, we do not observe it. We surely do observe it. Regardless of what your mathematical frame of reference may be, the camera doesn’t have to be moving with the axle to aid in our understanding of what’s happening there. There are plenty of science museums that have interactive exhibits showcasing the Coriolis effect; the phenomenon can be observed and understood even though the observer (in this case the museum guest) is in a stationary frame of reference. > [@watchwolf49](#): > > This is what I have for my home’s water meter, exact copy, a few of my neighbors as well: {eBay listing} [My apologies for this bad link, no time to figure out problem … please go to eBay and search the term “Sensus iperl 12S3GGXX” … that seems specific enough to get there if there’s one to be found] > > … $200 each … not bad compared to brand new impeller types with the reduced lead brass casings. Found [this listing.](http://www.ebay.com/itm/Sensus-iperl-12S3GGXX-Water-Meter-20-Year-Life-Lead-Free-Unprecedented-Accuracy-/252118285151?hash=item3ab36bbb5f:g:vnUAAOSw~bFWFxtQ) It says “no moving parts,” but that doesn’t mean it’s a Coriolis meter; it could be ultrasonic (though probably not, those aren’t cheap either), or it could be measuring the pressure drop across an orifice. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [March 15, 2016, 11:43pm UTC](https://boards.straightdope.com/t/is-the-coriolis-effect-a-mathematical-principle/748391/82 "2016-03-15T23:43:26Z")
Looked it up on the Sensus (sic) site: It’s a magmeter with “remanent field technology”. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [March 16, 2016, 12:12am UTC](https://boards.straightdope.com/t/is-the-coriolis-effect-a-mathematical-principle/748391/83 "2016-03-16T00:12:37Z")
This video [“The Coriolis effect”](https://www.youtube.com/watch?v=dt_XJp77-mk) demonstrates my point about which frame of reference the Coriolis effect is observed. When the camera shows the device in rotation, the thrown ball follows a straight line, as Newton’s 2nd Law of Motion predicts. Only when the camera is rotating _with_ the device, such that the device is stationary, do we see the thrown ball follow a curved line, that acceleration is the Coriolis effect. Spalding was not injured during the filming of this video. In the [video](https://www.youtube.com/watch?v=vxI9ibhVND8) posted in **Machine Elf’s** post #73, all the motion we observe is of the first case, the room is stationary, it is the apparatus that is in motion. All these motions can be described using the 2nd Law and the momentum vector. Rock fights on merry-go-rounds … any observer standing on the solid Earth will see straight line trajectories … only the observers _on_ the merry-go-round see the deflections caused by the Coriolis force. It’s all about frame of reference. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [March 16, 2016, 12:55am UTC](https://boards.straightdope.com/t/is-the-coriolis-effect-a-mathematical-principle/748391/84 "2016-03-16T00:55:09Z")
> [@ZurBob](#): > > Looked it up on the Sensus (sic) site: It’s a magmeter with “remanent field technology”. Yeah, I can’t find anywhere in their literature that says explicitly that the iPerl is a mass flow meter … so it most likely isn’t and I’ll humbly withdraw any statements concerning mass flow meters being cheap enough for local residential service … my apologies. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [March 16, 2016, 1:03am UTC](https://boards.straightdope.com/t/is-the-coriolis-effect-a-mathematical-principle/748391/85 "2016-03-16T01:03:22Z")
There is no apology necessary. [Previous page](https://boards.straightdope.com/t/is-the-coriolis-effect-a-mathematical-principle/748391.md?page=4)