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JOKE like no one’s listening. DANCE like a Mathematician

August 14, 2019

It must be the off season. Or the heat in the Northern Summer. Or desperation. Reader’s Digest has just published 37 Math Jokes.  Mathematicians are not known for the jokes. But here are 3 goodish ones.

ANS: He’ll stop at nothing to avoid them.

ANS: A roamin’ numeral.

ANS: Probably.

Here is a classic MATHSPIG JOKE:

And while we are being crazy cool kids here is a TED Talk on Mathematicians Dancing. I would call this a Mathfail because these guys DO NOT look as though they are having fun. Or, maybe, just maybe, the success of a joke or a dance is all in the delivery.

 

 

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The Equation that tried to break the internet!!!

August 3, 2019

The following equation went viral on Twitter like the Yanni & Laurel sound Tweet. What answer do you get?

The Equation that tried to stump the internet! New York Times

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The Simple Math of Cheap Ice Cream & Why It Melts So Fast

July 19, 2019

Discovery Magazine: Home Made Ice Cream

More ice cream science: the scoop baking

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Dangerous Math: Would You Survive a Shark Attack

July 5, 2019

Aussie Pro surfer, Mick Fanning, grabbed world attention when he was attacked by a shark in the Fanning J-Bay Open, South Africa on Sunday 19 July, 2015. Fanning was knocked off his board and forced to fight for his life. He survived. News.com

1 Mick fanning shark attack

One shark expert suggested the shark was a young great white shark under 3.5 m or 12 ft.

Would you survive a shark attack?

Let’s do the maths.

How fast can a shark swim?

According to the Smithsonian National Museum of Natural History:The torpedo shape of the great white is built for speed: up to 35 miles per hour (50 kilometers per hour). And then there are the teeth — 300 total in up to seven rows.

How fast can you swim?

According to Junior Olympic Games Qualifying Times 2015

For 13-14 yo 100m or 328 ft freestyle:

t girl = 1.15 or 75sec

t boy =1.10. Or 70 sec

Let’s assume you are an average swimmer but highly motivated on seeing a shark:

t kid = 100 secs

So you can swim 100m (328 ft) in 100 sec. But will you survive??????

 Surf Lesson Bluey’s Beach NSW 2009

We’re sooo tough in Australia! Shark, Smark! Whatever.

Picture from Daily Telegraph

Also according to the Smithsonian: Sharks can detect both the direction and amount of movement made by prey, even from as far as 820 feet (250 meters) away.

But there is hope as, according to the National Geographic Channel, Most shark attacks occur less than 100 feet or 30.5 m from the shore mainly around popular beaches in North America (especially Florida and Hawaii), Australia, and South Africa. 
3 Shark attack diagram Mathspig

4 shark attack maths mathspig

If average swimmer Dav is 100 ft (30 m) offshore and starts swimming when he sees the shark 820 ft (250 m) away, he would swim 63 ft (19.2 m) before the shark attacked. He is still 37 ft offshore. He might make it to shallow water. Or not!!!!

A Shark vs the World’s Fastest Swimmer

Again we will assume that the swimmer is 30m ( 100 ft) offshore when he sees the shark fin 250m (820 ft) away. But this time we will have the world’s fastest swimmer. This time we are talking Dav Holmes vs Shark!!!!!!!!!

5 shark attack Maths mathspig

If world champion swimmer Dav starts swimming when he saw the shark 820 ft (250 m) away, he would swim 163 ft (49.6 m) before the shark attacked. He would easily make it to shore before an attack. Dav would be swimming on sand.

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Eat Red Meat and Die ….. NOT NOW! ….. Maybe, sometime.

June 19, 2019

Here we go again.

“Eating even the moderate amounts of red and processed meat sanctioned by government guidelines increases the likelihood of developing bowel cancer” according to the above article in The Guardian, UK.

The sample size was 500,000. That’s good. It is a self-selecting sample. That’s not good. They could all be health fanatics. But here is the kicker:

“The researchers found those who ate the most and least red and processed meat tended to exaggerate their consumption or lack thereof.”

That’s a shock. People lie or exaggerate. Even the researchers then suggest – despite the screaming headline – that you don’t change your diet.

Although, looking at the plate above … I would!

Real Men Eat Red Meat and Die … Sometime!

Eat Meat and die??????

According to this headline in THE AUSTRALIAN 25th, March 2009   meat eaters are at risk of dying of cancer. The study published in  Archives of Internal Medicine involved half a million people over 10 years. So far so good. That is a good sample size. The sample consisted of people aged 50 to 71 years at baseline or, obviously, after 10 years 60 to 81years!!!!  So some deaths would be expected. Nevertheless, the article states: 

“Men whose red meat intake put them in the top 20 percent consumption band were 22 percent more likely to die of cancer in the 10 years of the study, compared to men whose intake was in the lowest 20 percent. For women, there was a 20 percent increase in risk.”

Here is the problem. Firstly and I quote from the original study: “Meat intake was estimated from a food frequency questionnaire administered at baseline.’ So they asked people once what their eating habits were then assumed they continued for the next 10 YEARS??? How likely are your eating habits to change in 10 years???

Secondly, and this was mentioned in the article without explaining the maths, big meat eaters tend also to be big drinkers, smokers, obese and the rest. This study has tried to separate out meat eating from other unhealthy lifestyle choices using the Cox Regression. Mathematical wizardry has produced these numbers but they don’t mean much. 

If the study used a control group of drinking, smoking, obese vegans then compared mortality rates over 10 years that would be interesting. But where do you find half a million of them???????? 

Finally,  the study  concluded ‘Red and processed meat intakes were associated with modest increases in total mortality, cancer mortality, and cardiovascular disease mortality.’ Not the stuff of headlines at all!!!!!!!

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How They Photoshop Supermodel Pics: THE MATH

June 13, 2019

Women’s Magazines have a strange kind of logic. On the one hand they push the philosophy ‘love yourself’, ‘love who you are’ and then they provide 365 pages showing you how to change every bit of yourself including your hair, eyebrows, pubic hair, tan, weight, skin tone, fitness, nose shape, career, boobs, how-to-hook him techniques and so on. Marie Claire, Australia, is no different. Nevertheless, I adopt the policy that these magazines are a bit of frou-frou fluff that women find entertaining. If girls and women want to beat themselves up with impossible goals then that is their right. But there are limits and the January edition, 2010 of Marie Claire is a classic.

Claiming to support real women and real body sizes Marie Claire ran a survey to see which body size 6,8, 10, 12, 14 or 16 was preferred by the Australian public.

Firstly, these surveys involve meaningless maths because they use  SELF SELECTING SAMPLES.  Nevertheless, there she is, the most popular choice, Size 12 or Ms 59%.

Keep flipping through the magazine, however, and you will find a shopping guide very common in these magazines. Have a look at the model (below)???? Do alarm bells ring?? Let’s do the maths, mathspigs.

 

Look at the pictures (above). The waist to hip measurement is the same for each model namely 20mm.  I’ve scaled up the images by factor of 10 (below) so that:

Waist to hip = 200mm.

Now, look at the leg lengths!!!!!!!!

 

Who is this model? Alice in Wonderland? Her legs are 89% longer than a girl with the same waist to hip length or have her legs been digitally stretched by 89%?

Teachers, I urge you to ask girls to bring in women’s/girl’s magazines to do some similar maths. To check if a model’s legs have been digitally stretched you can use the hip to knee and knee to ankle ratio which should be close to 1:1. We have to help girls develop a visual sense of proportion. And the maths quantifies this critical thinking. Rather than girls concentrating on booster bras boosting brains makes more sense.

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Don’t play it again Sam! The iPod, iPad & iPhone Shuffle

June 7, 2019

Here is an example of Gambler’s Fallacy, but for non-gamblers. 

We see – in this case – hear a pattern and then attribute meaning to this pattern  – It’s a conspiracy!!!! – when there is no pattern and no meaning!!!!! So Apple found when designing their iPod shuffle feature later on the iPad and iPhone. 

“When Apple first introduced the shuffle feature on its iPods, the shuffle was truly random; each song was equally likely to be picked than any other. However, the randomness didn’t appear random, since some songs were occasionally repeated, and customers concluded that the feature contained some secret patterns and preferences. As a result, Apple was forced to revise the algorithm. ‘We made it less random to make it feel more random,’ said Steve Jobs, the CEO of Apple’  

p68 The Decisive Moment How the Brain Makes Up Its Mind Jonah Lehrer (Text Publishing 2009)

dice

Try it. Pick 12 songs maybe off your playlist  – Your MP3 player, perhaps or a Top 20 Chart or Top 20 Downloads Chart – assign each song a number: 1, 2, 3….up to 12. Take two dice (Diehards Note:  It’s 1 die, 2 dice) and roll.

How many throws until you get 2 songs played in a row?