## Archive for the ‘Mad Mad Maths Fun in the Classroom’ Category

## QWERTY Math for MAC

April 16, 2018## Sasha a little dog with a BIG, BIG ID Number!

March 28, 2018## Amazing Maths Clock

March 17, 2018**Albert Digital Mathematical clocks are fascinating. **

**You calculate the time using +, -, x and ÷ . Such fun and ideal for the math classroom.**

**Mathspig found the Albert Mathematical clock at the Horsham International Hotel (below). **

**More info on the Albert Digital Clock here.**

**You can set the level of difficulty. You get 1 minute to work out the answer and that’s long enough.**

## And the Oscar for Best Mathematical Performance Goes to …..

March 5, 2018# ………………………………………..

# And the Oscar for Best Mathematical Performance Goes to …..

# Ben Zauzmer

**Ben Zauzmer, a Harvard Applied Math graduate who has a 75 per cent success rate in predicting the winners of Oscar Awards every year, has correctly predicted 20 of 21 winners in 2018 Oscars, which is a success rate of 95%. **

**How does he do it? He gathers thousands of data points on Oscar ceremonies over the past two decades – such as categories movies are nominated in, other award results, and aggregate critic scores – and he uses statistics to calculate how good a predictor each of those metrics is in each Oscar category. Then, he plugs in the numbers and that gives him the % chance that each film will win in each category according to the Boston Globe.**

**Ben, who writes for The Hollywood Reporter, uses his mathematical model to produce Bar Graphs like this:**

**This year the Best Picture was a close call, but Ben’s Mathematical Prediciton was correct. **

## Winter Olympics: Bad Math of Figure Skating Scores

February 22, 2018**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 win GOLD at Pyeong Chang 2018**

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.

## ……………………………………………………

# 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: Why do figure skaters spin so fast?

February 15, 2018

**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

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:

## 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.

## …………………………………………….

# 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 (v_{1} ) 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.

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.

## Winter Olympics: Beaten by 0.001 seconds

February 14, 2018

**In 2014 Winter Olympics Annette Gerristen (below) lost the Gold Medal in the 1000 m Women’s speed skate competition by 0.02 seconds.**

# What are the speed skating times for women?

# Women’s Speed Skating Calulations:

**Here are the speed calcs for Yara Van Kerkhof of the Netherlands in the 2018 Winter Olympics:**

# If Yara lost the Gold Medal by 0.02 secs (2 hundredths of a second) what would the distance be between the Gold and Silver place getters?

### When 1st and 2nd place are separated by 0.02 seconds, they are travelling at almost the same speed. So the second place contestant is:

## 23.8 cm behind the Gold Medalist

**The 2018 Olympic Gold Medalist in the 500m Women’s Speed Skating was Arianna Fontana.**

**Italy’s Arianna Fontana wins the 500 m Speed Skating 2018 Olympic Gold Medal in 42.569 seconds ahead of Yara van Kerkhof of the Netherlands and Kim Boutin of Canada. **

# Men’s Speed Skating:

# At longer distances the men’s speed skating speed is similar to the women’s speed above.

# If you lose by 0.001 secs…………

**Apollo Ono (below) competed in the 1500m men’s speed skating. He has won 8 Olympic Medals.**

**If a speed skater lost the Gold Medal by 0.001 seconds, the smallest measured time segment at the Olympics, they would be:**

# 1.19 cm

**behind the winner. That is less than the length of a small fingernail.**