Search for Actual Maths

2020/10/17

Mathematics in work: Energy & Environment Project Coordinator

As part of Cambridge Mathematics' Interviews and Intersections series, Energy & Environment Project Coordinator Zoe is interviewed about her work and life, and the place of mathematics within them.

Click below to read the post and then join the conversation on Twitter here!

Intersections: Mathematics and the energy & environment project coordinator

2020/07/27

What are the Chances? Lucky Tourist Cracks Safe Code

An open safe
Image by Sergei Tokmakov, Esq. from Pixabay

Prompted by an article with a very similar headline, this post at the link below looks at exactly how likely the situation in the article - a person guessing the correct combination to a specific safe first time - is:

2020/07/26

How Was 𝜋 First Calculated?

The Greek letter 𝜋 ("Pi", pronounced - at least in the UK - like "pie") when encountered in mathematics is usually used as shorthand for a pretty important number. This number can be defined in various ways, but arguably the simplest is "the ratio of a circle's circumference to its diameter." To put it another way, 𝜋 tells you how many times bigger the circumference is than the diameter; or it's the number you get if you divide a circle's circumference by its diameter:

\[ \pi = \frac{C}{d} \]

Circumference, Diameter & Pi by T.Briggs is licensed under CC BY-SA 4.0

One way that 𝜋 could be calculated is by measuring the diameter and circumference of a given circle and dividing the latter by the former. But one of the reasons we might want to know a value for 𝜋 in the first place is that it is difficult to measure the circumference of a circle.

2020/07/25

Big Ben Strikes Again

Big Ben (well, its tower, lit up at night) Photo via Good Free Photos

This piece of Actual Maths concerns the third episode of the original Captain Scarlet TV series, Big Ben Strikes Again. You can watch it online via Amazon Prime, buy it on DVD, or probably find it elsewhere if you do some Googling. Maybe you've got a dusty old DVD lying around somewhere already or, if you're really retro, a video.

I loved watching repeats of Thunderbirds, Stingray and Captain Scarlet when I was growing up, but the first time I heard about this lovely example of Actual Maths was as the subject of a talk by Matthew Scroggs at Big MathsJam.

If you want to watch the episode before risking spoilers you'll probably want to stop reading about here and come back when it's finished.

2020/07/19

The Cube

A 14 minute podcast exploring the most basic of 3D shapes, the cube, exploring where they turn up in our modern world, why they aren't used more and what one looks like in four dimensions!

2020/07/18

De-wobbling Tables

Helen sent me this:
I'm not sure where this originated, so apologise for the lack of a reference. I'll happily update if someone can point me in the right direction! In the mean time I'll just link to the tweet I was sent.

I've heard this before: if you're suffering from a wobbly four-legged table don't mess around with trying to fold a napkin or stack beer mats to just the right thickness. Instead just turn the tables on that problem by... turning the table. Twist it around its own axis of symmetry and, within a quarter turn, you'll have a stable table.

There's a reason why this works and one of the places you can find out about that is in the Numberphile video embedded below:

2020/07/16

What's the point of... Imaginary Numbers?

A poster detailing some of the uses of imaginary numbers:

This is a reduced-size image. Download the full-resolution poster at the link below.


What Do the Percentages Mean on Steep Road Warning Signs?

Maths teacher Simon Young tweeted a thread about percentages on road signs, and he's given me permission to write it up as a blog post. I've stayed faithful to Simon's original wording, with a little editing here and there, mostly based on his own corrections and some of the conversation resulting from his thread (the original thread is linked at the end).

Road steepness is expressed as a percentage on UK road signs: what does it mean, and where do the numbers come from?

Have you ever wondered what the percentages mean in those road signs about an upcoming gradient change? I know I have! Here is what I discovered...

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