Measure the Earth’s Radius! (with this one complicated trick)

Hannah’s book is out now!

CORRECTIONS
- None yet! Let me know if you spot any mistakes.

Protractors by Matt Parker
Music by Howard Carter
Design by Simon Wright and Adam Robinson

MATT PARKER: Stand-up Mathematician

[olmostgudinaf]

Are you saying that the Shard security did not let you in with weapons of maths instruction?

[FadeGrayOG]

"The thing is, we got a number"

This is the professionalism we subscribe for.

[redumptious]

Ah yes, the age old joke: “Two mathematicians go to the shard with a fancy protractor and a laser-inclinometer…”

[smmk]

“You know what Hannah, it’s a small world”

Couldn’t stop laughing xD

[bencheevers]

"Oi you got a license for that?"
"It's a protractor"
"Exactly, obviously a weapon"

[jimmyzhao]

This demonstration is so convincing, I've gone from being a *'Flat Earther'* to a *"Small Earther'*

[PetruRatiu]

I love how Hannah started all serious and embarassed by Matt's antics and got progressively more Parkerish as the video progressed.

[poutouellet]

Matt: "I've got this really fun idea on how we can do publicity for your book!"
Hannah: *sigh* "Can't you just mention it on a video or something?"

[danieljensen]

Hannah: "We're going to go up the shard with an electrical inclinometer and then do one calculation after looking some stuff up on Wikipedia."
Matt holding his makeshift plumb bob inclinometer and cubit shoes: "We are not!"

[telotawa]

"anything between 10 and a million"
the Parker radius, everybody

[ThatPsdude]

This is why I love Matt Parker. The hard work, dedication, and attention to detail is all there!...unlike the correct answer, but expectations were set. I nominate that this non-negative, _well within_ an order of magnitude radius of the Earth be called a Parker Earth Radius.

[brachypelmasmith]

this reminds me of the time when we were calculating the speed of muons using two scintilator detectors. But we used rulers to measure the distance between those so we got end result of c+-c. Which is technically correct answer for any question regarding speed asked ever.

[Mewguy]

Matt and Hannah have such great chemistry together on screen. It’s wonderful to see them working together! Especially seeing Hannah get fed up with Matt’s shenanigans.

[MisterNohbdy]

As Matt keeps stacking scope-creep onto the required tasks in this project, I can sense Hannah's "I did not sign up for all this" energy.

[Jiggerjaw]

Matt is the perfect foil for Hannah. I love it every time these two collaborate.

[perryheun]

Matt Parker is such a maths geek his body is metric.

[redumptious]

“Well we’re not going to just calculate the sine of the angle. I built my very own lookup table last night just for that!”

[danagritz]

As a land surveyor, this was equal parts hilarious and hard to watch while yelling at the screen. I know how much a slight angle mismeasurement can add up. Compounding this with a less than accurate distance. I was actually very relieved to see how far off your calculation was. I didn't want people thinking they could be this rough with their measurements and come out anywhere close to an accurate answer

[xevira]

They measured the Parker height of the Shard, the Parker angle to the horizon, the Parker radius and circumference of Earth.

Bravo. Well done, Matt and Hannah.

And, can we give an Honorable Mention to the Parker cubit? They really did a lot of the footwork in all of this.

[angelogandolfo]

Matt’s almost child-like enthusiasm (I mean that as a compliment), combined with Hannah’s calm, slightly exasperated, yet kind, patience, make for a great team! (“Yeah yeah yeah, I want to measure the height of the shard!!!”…. (Rolls eyes).. “Ohhh, OK then……..”