Uploaded April 2019 | Updated September 2026, 1 week ago
Does the Earth really spin?
If it did, wouldn't that generate a lot of centrifugal force? How much?
Which direction would that force point?
How can we test for that?
This video was inspired by Larry Lowe - one of the more prolific commenters on my channel. Larry has some really good insights about gravity and centrifugal force, but he clearly hadn't worked the math all the way to see if his intuition was correct.
In this video, I'll work the math a little more slowly than I normally do. This may be a bit boring for my usual subs, but for people like Larry, I hope that this can inspire them to practice with this type of analysis.
Maybe Larry will see that I really am telling the truth about what the math says. Maybe Larry will be inspired to see these issues as a call to investigate further instead of a call to make accusations and declare his own superiority.
jump ahead:
@0:00 Intro
@0:22 The premise. "Won't we fly off?"
@0:53 Is centrifugal force a real force?
@1:18 The equation for centrifugal force
@1:49 Estimating the amount of centrifugal force at the equator
@4:02 Estimating the amount of centrifugal force at 45 degrees latitutde
@5:24 Combining gravity and centrifugal force
@6:10 A close-up on vector addition
@12:28 Concern about the angle between gravity and centrifugal force
@13:48 Will this angle cause a ball to roll towards the equator?
@15:56 Getting to the result... What does "level" really mean?
@17:31 Gotcha! If this were true, the Earth couldn't be a perfect sphere!
@18:20 Gotcha! Nobody ever mentioned this before!
@19:23 Science education ALWAYS reduces the complexity of the situation. You ALWAYS have to dig deeper to find more details.
@20:09 We can measure the weight of an object at different places on the Earth. Thanks Critical Think!
source material:
josselinTUBE "CENTRIFUGEUSE - ROTOR @ FOIRE DU TRONE (GoPro)" youtube.com/watch?v=GspwbZSjABA
Critical Think "Zero Probability: Flat Earth" youtube.com/watch?v=f4o-NXUSXl8
Critical Think "Zero Probability: Flat Earth - Part 2: The method" youtube.com/watch?v=8qUQtEynaTU
Critical Think "Zero Probability: Flat Earth - Part 3: Error Analysis" youtube.com/watch?v=5bf5EiXCmpk
Does the Earth really spin?
If it did, wouldn't that generate a lot of centrifugal force? How much?
Which direction would that force point?
How can we test for that?
This video was inspired by Larry Lowe - one of the more prolific commenters on my channel. Larry has some really good insights about gravity and centrifugal force, but he clearly hadn't worked the math all the way to see if his intuition was correct.
In this video, I'll work the math a little more slowly than I normally do. This may be a bit boring for my usual subs, but for people like Larry, I hope that this can inspire them to practice with this type of analysis.
Maybe Larry will see that I really am telling the truth about what the math says. Maybe Larry will be inspired to see these issues as a call to investigate further instead of a call to make accusations and declare his own superiority.
jump ahead:
@0:00 Intro
@0:22 The premise. "Won't we fly off?"
@0:53 Is centrifugal force a real force?
@1:18 The equation for centrifugal force
@1:49 Estimating the amount of centrifugal force at the equator
@4:02 Estimating the amount of centrifugal force at 45 degrees latitutde
@5:24 Combining gravity and centrifugal force
@6:10 A close-up on vector addition
@12:28 Concern about the angle between gravity and centrifugal force
@13:48 Will this angle cause a ball to roll towards the equator?
@15:56 Getting to the result... What does "level" really mean?
@17:31 Gotcha! If this were true, the Earth couldn't be a perfect sphere!
@18:20 Gotcha! Nobody ever mentioned this before!
@19:23 Science education ALWAYS reduces the complexity of the situation. You ALWAYS have to dig deeper to find more details.
@20:09 We can measure the weight of an object at different places on the Earth. Thanks Critical Think!
source material:
josselinTUBE "CENTRIFUGEUSE - ROTOR @ FOIRE DU TRONE (GoPro)" youtube.com/watch?v=GspwbZSjABA
Critical Think "Zero Probability: Flat Earth" youtube.com/watch?v=f4o-NXUSXl8
Critical Think "Zero Probability: Flat Earth - Part 2: The method" youtube.com/watch?v=8qUQtEynaTU
Critical Think "Zero Probability: Flat Earth - Part 3: Error Analysis" youtube.com/watch?v=5bf5EiXCmpk
