What are the Chances? Lucky Tourist Cracks Safe Code

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:

What are the Chances? at tommaths.blogspot.com

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.

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.

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!

Marcus du Sautoy's Five Shapes: The Cube

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:

What's the Point of... Inequalities?

A poster introducing some uses of inequalities:

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

What's the point of... Inequalities?

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's the point of... Imaginary Numbers?

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...

What's the point of... Graphs?

A poster describing some of the uses of graphs:

This is a reduced-quality image: download the full-resolution version at the link below.

What's the point of... Graphs?

The Maths of Pointless

How often do we come up against people who are convinced that mathematics is pointless? TV game show Pointless requires contestants to obtain the lowest score to win against their opponents. Plus magazine discusses the maths behind this idea in two articles. The first looks at luck and unluckiness in TV game shows (with reference to Pointless); the second looks at some of the more general mathematical ideas related to Pointless specifically.

1. Pointless: The maths of TV gameshows

2. A Pointless return!

What is a Black Hole?

Over at Plus Magazine, this interview discusses what black holes are and how to describe them mathematically.

What is a Black Hole - Mathematically?

You can also find out more about black holes at Blogstronomy! 

What's the point of... Geometry?

A poster suggesting some of the uses of geometry.

This is just a thumbnail: click the image or use the link below to download a high-resolution version from the originator.

What's the point of... Geometry?

What's the point of... Exponentials?

A poster introducing some of the uses for exponential functions.

This is just a thumbnail: download the full-resolution version at the originator's website (click on the image or the link below).

What's the point of... Exponentials?

What's the point of... Distributions?

A poster introducing some of the uses for statistical distributions.

This is just a thumbnail: click the image or the link below to download the full-resolution version from the originator's website.

What's the point of... Distributions?

What's the point of... Differentiation?

A poster presenting some of the uses of differentiation.

This is just a thumbnail: click the image or the link below to download the full-resolution version from the originator's website.

What's the point of... Differentiation?

What’s the point of... the Binomial Theorem?

A poster presenting some of the uses of the Binomial Theorem.

This is just a thumbnail: click the image or the link below to download a full-resolution version from the originator's website.

What's the point of... The Binomial Theorem?

What's the Point of... Algebra?

A poster presenting just a handful of uses of algebra.

This is just a thumbnail: click on the image or the link below to download the full-resolution version from the originator's website.

What's the Point of... Algebra?

What’s the point – Aerial Photography

Free printable posters discussing some of the mathematics represented in a photograph of a street performer.

This is just a thumbnail: Click the image or the link below to download the full poster from the originating site!

What’s the point – Index Jump

Mathstonbury

Some maths teaching activities based on Glastonbury! This is a lot more contrived than much of the stuff I try to link to on here, but having been part a festival committee many moons ago the general idea of some of these is close to bits of the reality.

Mathstonbury at Mathmaticow.com