## How random is a random NUMBER GENERATOR? The problem with the iPod, iPad & iPhone Shuffle

April 18, 2023

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)

Try it. Pick 12 songs to make your playlist.

USE The Random Number Spinning Wheel HERE

Keep in mind that writing a program for a RANDOM NUMBER GENERATOR is difficult as all programs are based on some pattern. Click the Spinning Wheel link above and  spin the wheel 12 times.

What happened? Did you get too many repeats like the iPod Shuffle customers who complained?

## Real World Maths: Surds and all that jazz …

October 12, 2022

Eddie Woo is an Aussie Maths teacher who runs his own Youtube Channel. So popular is this channel in October 2015, Woo won the NSW Premier’s Prize for Innovation in Science and Mathematics. This youtube clip won’t tell you where you will use surds, but it does something magical.

It compares surds to different kinds of music to help students understand why mathematicians go crazy over the concept of surds. This clip tells why maths is soooooo special. There is no guesswork or fake information in this maths. Maths must be accurate. And surds demonstrate this point. (Look for the 5 min mark)

## Will you use surds in real life?

Maybe. Probably, not. But surds are used in mathematical programs that demand accuracy. eg. engineering skyscrapers, building satellite dishes, and even in video games. But you won’t see them. Like so much mathematics surds will be hidden in some algorithm.

Here are two Examples:

# 1. The Golden Ratio:

Often written a 1:1.61 the Golden Ratio or Fibonacci Sequence appears in art and nature and has an aesthetic appeal to the eye, but the accurate ratio is:

Satellite dishes, headlights, torches, and bridges all designed using the parabolic arc. The parabola is defined by the quadratic function and sometimes solving for x produces an irrational no. namely a surd. Rounding off can introduce inaccuracies that can become more dramatic when scaled up to the sie of, say, a bridge.

# 3. The Golden Ratio in Music

Mozart arranged his piano sonatas so that the number of bars in the development and recapitulation divided by the number of bars in the exposition would equal approximately 1.618, the Golden Ratio. Find more @ CLASSIC FM.

Back to Mozart.

In the above diagram, C is the sonata’s first movement as a whole, B is the development and recapitulation, and A is the exposition.

And here is Mozart’s Piano Sonata No. 1 in C Major as an example. Can you hear the Golden Ratio. Not really. But it’s there.

## DART vs ASTEROID: Middle School Math

September 27, 2022

# Guess what?

## When Area Calcs mean Big Bucks

August 25, 2022

Bank Notes returned to RBA data.

RBA grids for damaged notes.

## MIDDLE SCHOOL MATH: Mapping, Matrices and GAME DEVELOPMENT

August 7, 2022

The aim of this post is to show middle school math students that MATRICES are used in the REAL WORLD of GAME DEVELOPMENT.

They don’t have to do the math.

To have some fun playing with a 2D to 2D transformations go to this MathIsFun post.

## Crazy Guy uses Infrared Sensors on Xbox Kinect to create WoW! Synth-Pop VIDEO

August 7, 2022

The aim of this post is to show middle school math students that MAPPING is used in the REAL WORLD of Synth-Pop Music Video Production.

## Amazing and Terrifying Wildfire Math . . . . . . . . . . . . . . USA UNITS

July 25, 2022

With wildfires burning across the US and Europe , Mathspig had to update this firefighter math for middle school classrooms.

Wildfires USA 2022 Map:NASA

# Background Story

On 5th August 1949 Wag Dodge was dropped by parachute with 14 other fire fighters into Mann Gulch, a steep-sided gully in a Montana pine forest. Fire fighters who parachute in to put out small blazes started by lightening are called Smoke Jumpers. As they worked their way down the sides of the gully the breeze was blowing away from them. But the wind soon shifted. This produced an updraft, which increases the speed of the fire front. The 15 Smoke Jumpers turned and started running for their lives uphill.

# USA UNITS

## Time Trial:

Mark out a 30ft course. Make 3 time trials.

t1 =

t2 =

t3=

tav = (t1 + t2 + t3)/ 3 =

Your Speed S = 30/tav   ft/sec

# HOW FAST IS A GRASS FIRE?

This will, of course,  vary depending on the wind speed. A typical grass fire in Australia in a flat area can travel at 12mph (up to 20mph) in a gentle breeze.

Fire Front Speed Grass Fire

Fire Front Speed = 12 mph = 12 x 5280/(60 x 60)

= 17.6 ft/sec

= 18 ft/sec

# CAN YOU OUT RUN A FIRE?

Average Running Speed Boy 13–14 yo = 10 ft/sec

Average Running Speed Girl 13–14 yo = 8 ft/sec

We’ll assume, boy or girl, that you are really motivated and can run away from the fire at top speed of 10 ft/sec and -Wow! – this is easy math. Now calculate the distance you can run and the fire front moves in 10 secs intervals up to 1 minute.

This is not looking good. See more Firefighters Need Maths here.

We can do very accurate calculations using simultaneous equations. Wildfire Algebra: Detailed Worksheet using simultaneous equations and solutions  here.

## NOW YOU ARE RUNNING UP HILL. WHAT HAPPENS?

We’ll assume, due to being motivated by having a fire licking your heels, that you can run at your top speed up hill for a short time, at least. But here is the problem.

Heat rises and so there is a Chimney Effect pushing the fire uphill. The rule of thumb used by fire fighters is:

Each 10º increase in slope, the fire front speed doubles.

Now you can calculate the distance travelled up a slope at a 30º angle.

Don’t forget you can use the WEB 2.0 Calculator here

Even at your top running speed, which is unlikely up a slope, you can run 1080 ft in 1 minute. In that time the forefront has moved 8640 ft or 1.6 miles. It depends how far away you are from the fire front when you start running, but it seems likely that you cannot out run this fire front.

Again we can do very accurate calculations using simultaneous equations.

See Firefighters Need Maths here.

Wildfire Algebra Worksheet and solutions  here.

# CAN YOU OUT RUN A WILD FIRE?

High winds can turn a bush or forrest fire into a WILD FIRE with wind speeds up to 70 mph and temperatures up to 2000 °C, which can and does melt glass and cars.

The fire front speed doubles with every 10º, so speeds for the fire front in a strong wind can reach 140 mph, 210 mph and up to 280 mph.

# What happened to the Smoke Jumpers?

When the fire front changed direction Wag Dodge and 14 other Smoke Jumpers found themselves running for their lives up a steep slope. What did Wag do next?

ANS: Here’s the amazing thing. Wag realised he could not out run the fire at that point. So he stopped. Took off his back pack. Took out some MATCHES and lit a fire in the grassy patch in front of him. Just before the firewall hit he threw himself face down on the burnt patch. He survived. The other 14 firefighters did not.

## Amazing and Terrifying Wildfire Maths . . . . . . . . . . . . . . METRIC UNITS

July 25, 2022

With wildfires  burning across the US and Europe , Mathspig had to update this firefighter maths post for middle school classrooms.

Radiant Heat Stats WA Fire Dept FACEBOOK, Australian Bushfires 14 NOV 2019 MyFireWatch WA

Wildfires USA 2022 Map: NASA

# Background Story

On 5th August 1949 Wag Dodge was dropped by parachute with 14 other fire fighters into Mann Gulch, a steep-sided gully in a Montana pine forest. Fire fighters who parachute in to put out small blazes started by lightening are called Smoke Jumpers. As they worked their way down the sides of the gully the breeze was blowing away from them. But the wind soon shifted. This produced an updraft, which increases the speed of the fire front. The 15 Smoke Jumpers turned and started running for their lives uphill.

# METRIC UNITS

## Time Trial:

Mark out a 10 m course. Make 3 time trials.

t1 =

t2 =

t3=

tav = (t1 + t2 + t3)/ 3 =

Your Speed S = 10/tav = ……… m/sec

## HOW FAST IS A GRASS FIRE?

This will, of course, vary depending on the wind speed. A typical grass fire in Australia in a flat area can travel at 20kph (up to 30 kph) in a gentle breeze.

Fire Front Speed Grass Fire

Fire Front Speed = 20 kph = 20 x1000/(60 x 60)

= 20 x 0.27777777 = 20 x 0.28 m/sec

= 5.6 m/sec

# CAN YOU OUT RUN A FIRE?

Average Running Speed Boy 13–14 yo = 3.0 m/sec

Average Running Speed Girl 13–14 yo = 2.4 m/sec

We’ll assume, boy or girl, that you are really motivated and can run away from the fire at top speed of 3.0 m/sec. Now calculate the distance you can run and the fire front moves in 10 secs intervals up to 1 minute.

This is not looking good. See more Firefighters Need Maths here.

We can do very accurate calculations using simultaneous equations. Wildfire Algebra: Detailed Worksheet using simultaneous equations and solutions  here.

## NOW YOU ARE RUNNING UP HILL. WHAT HAPPENS?

We’ll assume, due to being motivated by having a fire licking your heels, that you can run at your top speed up hill for a short time, at least. But here is the problem.

Heat rises and so there is a Chimney Effect pushing the fire uphill. The rule of thumb used by fire fighters is:

Each 10º increase in slope, the fire front speed doubles.

Now you can calculate the distance travelled by the fire front up a slope at a 30º angle.

Don’t forget you can use the WEB 2.0 Calculator here.

Even at your top running speed, which is unlikely up a slope, you can run 180 m in 1 minute. In that time the forefront has moved 2688 m or 2.7 km.

It depends how far away you are from the fire front, but it seems you cannot out run this fire front.

Again we can do very accurate calculations using simultaneous equations.

See Firefighters Need Maths here.

Wildfire Algebra: Worksheet and solutions here.

# CAN YOU OUT RUN A WILD FIRE?

High winds can turn a bush or forrest fire into a WILD FIRE with wind speeds up to 110 kph and temperatures up to 2000 °C, which can and does melt glass and cars.

The fire front speed doubles with every 10º, so speeds for the fire front can reach 220 kph, 330kph and up to 550kph.

# What happened to the Smoke Jumpers?

When the fire front changed direction Wag Dodge and 14 other Smoke Jumpers found themselves running for their lives up a steep slope. What did Wag do next?

ANS: Here’s the amazing thing. Wag realised he could not out run the fire at that point. So he stopped. Took off his back pack. Took out some MATCHES and lit a fire in the grassy patch in front of him. Just before the firewall hit he threw himself face down on the burnt patch. He survived. The other 14 firefighters did not.

June 19, 2022

## No Frills MATHs Skills for Parents 4: FRACTIONS for Beginners

June 6, 2022

Here is a post on Lego Fractions by New York Grade 3 teacher Alycia Zimmerman. Surprisingly I found this on an art website.

Just play with the Lego blocks. Add and subtract … you can even multiply and divide.

Next time.