OMG! Credit Card Antenna Geometry is so cool + some PIN Probability

The world  has mostly agreed on the size of a credit card:

Credit cards today contain a microchip and aerial.

A credit card is dissolved in ACETONE (solvent found in some nail polish removers) to extract the chip & aerial in this BBC video.

 

OMG! It still works to pay for coffee but if you wanted cash you would still need the PIN.

Halloween Math: Witches vs Zombies 2

 

Halloween Math : Witches vs Zombies 1

There has been a real world Witches Vs Zombie Fight.

The witches of the Haunted House in Salem, Massachusetts, are at war with the Zombies of The Nightmare Factory nearby. A witch tripped a Zombie who was wearing a straight jacket!!!! And … read it for yourself in the Daily Mail, UK.

Links: Top Grossing Horror Movies

Blair Witch Project Budget here.

Stranger Things Math 2: Now You are the Galton Ball

Mathspig has become obsessed with the Galton Board since watching ELEVEN dropping discs into the peg board on STRANGER THINGS 4.

Now thanks to David Butler, University of Adelaide, you can turn your middle school class into Galton Balls. You can find 100 randomly generated instruction sheets for each human Galton Ball at David’s website. (Link above)

Ideally, you would have 3,000 students to do this activity. But the class exercise ends with something approximating a Normal Distribution or Bell Curve constructed from video tap casettes. And the NOrMal Distribution is spooky.

More on the Galton Board Math here.

Stranger Things Math: Eleven and the Galton Board

NOTE: Michael (above), who seems appropriately scary for this post, uses a commercial Galton Board.  It has one flaw. Many balls feed into the grid at once and this will change the pathways taken because the balls bump into one another. The best results come from dropping in the balls one at a time. If you had the patience to drop in 3,000 balls one at a time.

FOR THE LONGEST KICK or THROW in Football you need this MATHS

………………………………………………

The following maths is suitable for Year 9+

but can be presented to lower grades just to show

maths is cool!

Mona Chalabi’s Data Art: Maths never looked so good even the dick graphs

Mona Chalabi is a British-Iraqi data journalist and illustrator based in London. She specialises in all things data.

An outstanding communicator her work proves that MATH can be artistic and ART can be data-based. She is an honorary fellow of the British Science Association.

Mona Chalabi Self Portrait on INSTAGRAM

WARNING: Mona Chalabi INSTAGRAM account is politically graphic and contains sexually explicit graphs. Yeah! Dick graphs etc. The Instagram links in this post connect with individual illustrations.

1. Mona Chalabi on Jeff Bezos’ Wealth. 

I found Mona Chalabi through her illustrated New York Times article (7 April, 2022) 9 WAYS TO IMAGINE JEFF BEZOS’ WEALTH. 

So Jeff Bezos personal wealth is $172 Billion (US$) Her Toblerone Block vs Mt Everest comparison was in this article.

NOTE: Median wealth is the mid-point wealth ie. 50% of Americans have more wealth. 50% of Americans have less wealth.

2. Mona Chalabi CAFFEINE DATA ON INSTAGRAM

Mona also includes relevant the data in her posts. eg.

 

3.  Mona Chalabi on OUR MOST COMMON FEARS on INSTAGRAM

4. Mona Chalabi on Earth’s Orbit on INSTAGRAM

Killer Easter Egg Math

According to The Guinness Book of Records the largest chocolate Easter Egg went on display at Le Acciaierie Shopping Centre, in Cortenuova, Italy, on 2011.

 Egg Weight   = 7,200 kg  = 15,873 lbs

Height = 10 m =  34 ft

Circumference = 19.6 m = 64 ft

The sugar content for easter eggs is: 55-65% by weight

So we will assume the sugar content of the giant egg was in the middle:

60%

The weight of sugar in the giant egg equals:

NATHAN CHEN wins Gold but Figure Skating Scores can be BAD MATH

Nathan Chen, 22, USA, wins GOLD in the Men’s Figure skating with 5 brilliant, soaring quadruple jumps executed to perfection to Elton John’s “Goodbye Yellow Brick Road” and “Rocket Man.”

Nathan Chen’s Winning Performance on You tube HERE.

According to the fab NBC video, Mathletes,  nine Figure Skating judges score competitors for the complexity of each element (eg. Triple axel or triple spin jump) and the quality of the performance producing a score out of ten.

Tessa Virtue and Scott Moir(Above) GOLD Medal performance at Pyeongchang 2018 here.

Kailani Craine, Australia

This is a typical figure skating score card for one competitor.

The final score, however, is based  on the average for only 5 of these scores. Two are eliminated by random selection (Red Brackets). Then the top and bottom scores are removed and the remaining five scores averaged.

Screen grab NBC Mathletes

……………………………………………………

Now consider the IDENTICAL SCORE CARDS

of Skater A & B:

Skater A:

Four scores are removed. Two by the random selector (in brackets) and then the top and bottom scores (with line drawn through them)

7.00 + 7.00 + 7.00 + 6.75 + 7.00

……………………………………..

=  34.75/ 5 = 6.95

Skater B:

Four scores are removed. Two by the random selector (in brackets) and then the top and bottom scores (with line drawn through them). But this time the random selector eliminates two low scores.

The average:

7.00 + 7.25 + 7.00 + 7.00 + 7.00

……………………………………..

=  35.25/ 5 = 7.05

Same score cards but Skater B gets a higher average score than Skater A.

Skater A is, in fact, beaten by a random number selector!!!!

Winter Olympics 2022: Why do figure skaters spin so fast?

Here is the sensational pairs team from the 2018 Winter Olympics.

But why do ice skaters spin so fast?

Here is the math!

REASON  1:

Well, mathspiggies, the girl in this video is right. Angular momentum remains constant unless external forces are applied.

L = mvr

L = angular momentum

v = linear velocity

r = separation of object

Louisa Barama, USA

Let’s have a look at this equation:

The fastest spin on ice skates was achieved by Natalia Kanounnikova (Russia) with a maximum rotational velocity of 308 RPM (rotations per minute) at Rockefeller Centre Ice Rink, New York, USA on 27 March 2006. See Guinness Book of Records.

 Record spin :  v_r = 308 RPM

Other spins include:

Mao Asada, Japan, triple Axel

Triple Axel spin v_r = 220 – 280 RPM

……………………………………………………………………………………………..

 Maximum Triple Axel spin v_r = 402 RPM

Skaters can spin faster during a triple axel jump because there is no friction from the ice slowing their spin.

To complete a quad axel, it’s estimated that the skater would have to rotate in the air at:

540 rpm.

…………………………………………………………………………………

Camel spin v_r = 90 RPM

More info here.

Kim Yuna, South Korea

…………………………………………….

REASON 2:

How can a figure skater move from

a camel spin into a very fast standing spin?

Now, mathspiggies, you must separate Linear Velocity (v₁ ) from Angular Velocity (v_r ). Linear Velocity is measured in m/sec ie. it is the speed of, say, a skaters foot around the circle. Angular Velocity is measured in either RPM (Revolutions Per Minute) or degrees or Radians per minute. Ie. It is the rate of spin. We can’t judge how many m/sec a skaters foot is moving in a circle. We can only see how fast they spin. In other words, we see their Angular Velocity. When a skaters foot is in the Camel position that foot travels in a very big circle.

But when that same foot is in a Triple Axel postion it moves in a very, very small circle.

Patrick Chan, Canada, Camel Spin

Patrick Chan, Canada, Triple Axel

By halving the radius, firstly, a skater’s Linear Velocity doubles due to the conservation of angular momentum.

Then, secondly, by halving the radius the circumference of the circle moved by , say, the skaters foot is halved.

Overall, by doubling the velocity around the circle and halving the circumference a skater increases their rotational velocity by a factor of 4.

Look at the numbers:

Camel spin v_r = 90 RPM

…………………………………………………………………………………

Triple Axel spin v_r = 4 x 90 RPM = 360 RPM

That’s about right.