Posts Tagged ‘Maths’

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

November 13, 2019

mathspig-smoke-jumpers 

With the catastrophic Californian fires burning into November and wildfires currently burning in NSW and Qld, Australia, I had to repost this firefighter maths for middle school classrooms.

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

 Wildfires USA 2019 Map: Ecowest,

mathspig-metric-units-fire-math

METRIC UNITS

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.

HOW FAST CAN YOU RUN?

METRIC UNITS

Time Trial:

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

t1 =

t2 =

t3=

Average your time:

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

Your Speed S = 10/tav = ……… m/sec

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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

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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.

mathspig-fire-fighter-table-1

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.

mathspig-cfa-diag

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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.

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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.

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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.

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Braindead Math for Halloween

October 29, 2019

Tarantino, being a connoisseur of Fake Blood, used several types of Fake Blood in the film Kill Bill II ranging from good splatter to free-flowing blood. According to one fanzine, in this film, Uma Thurman killed 88 opponents with a sword.  So the numbers(above)are in the right ‘blood-soaked’ ballpark. More survival math (The Hunger Games) here.

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Why do so many students HATE MATH? … um, you know, BOREDOM

September 28, 2019

According to ‘Bored Out of Their Minds’, an article by ZACHARY JASON in The Harvard Ed Magazine (2017):

Boredom accounts for nearly a third of the variation in student achievement. 

Half of high school dropouts cite boredom as their primary motivator for leaving.

Boredom begins for Math students at Grade 6 when students (Common Core Standards, USA) tackle more abstract concepts such as linear eqns, exponents, probability, geometry and so on.

Math curriculums in the USA, UK & Australia all demand students solve REAL LIFE problems. Too often these are of the type:

Q. Ronaldo has tethered his goat on a 12ft rein in the corner of a 20ft square field. What area can the goat graze?

THE ANS: Who cares?

Simple.

Ask students maths questions which have answers they want to know.

Students really don’t care about Ronaldo’s goat, but here are some questions which involve intriguing answers they might want to work out. And many of these questions involve funny or age-relevant activities, which also helps engagement.

1. Mean, Median STATS: Mean, Median and Coffee: Busting an Urban Myth

2. Parabolas: Can you beat the 12-14 yo World Record for a Watermelon Pip spit?

3. Geometry: Build a Freestanding Tower

Rates (Speed) & Units:

4a. The Terrifying Math of Running from a bear

USA Units

METRIC UNITS

4b. How old is your hair?

5. Decimals, %, Volume: What Volume of alcohol is lethal for teens?

6. Decimals, Algebra, Weight Units

How much blood can a kid lose and survive?

USA UNITS

Metric Units

Graph Hunger Game Math

7. GEOMETRY. Angles

Why killer heels can kill!

Any Topic:

8. Middle School Math Photo Scavenger Hunt

9. Write Your Own Math Song

Space Math Song here

10. Make a Math Poster

EVEN TEACHERS GET BORED!!!

The average time it takes an audience at a conference to switch off is 11 minutes. Keep in mind this audience is, at least, being paid to be bored witless.

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Can you escape a FALLING TREE?

August 24, 2019

Tragically, 5 people have been killed by falling trees in Victoria, Australia, this Winter. 

In 3 separate accidents, 4 died when trees crushed the occupants in cars. One victim was a pedestrian.

So if you were walking through a park could you escape a falling tree if you either heard a cracking sound or saw the tree starting to fall?

With thanks to Physics Stack Exchange.

For an inverted pendulum near the top of its arc, there is no period, but the quantity ℎ/𝑔 does represent a characteristic time scale for this system. The tree will take a few of these characteristic times to fall.

Mathspig hates seeing an old tree felled, but it does give us the necessary time data.

 

There are many assumptions in these calculations.

*You’d be hit by the tree trunk, not a branch which would hit you sooner.

*There is no wind pushing the tree over.

*The tree falling is an approx to a reverse pendulum.

 

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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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FRANTIC FRIDAY: Crazy Math Word Maze USA edition

June 3, 2019

PDF file: Crazy math maze work sheet 1 USA

PDF file: Crazy math maze work sheet 2 USA

CRAZY MATH MAZE WORKSHEET ANSWER

PDF File: Crazy math maze work sheet ANS USA

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FRANTIC FRIDAY: Crazy Maths Word Maze UK edition

June 2, 2019

PDF file: 1. Crazy math maze work sheet 1 UK

PDF file: 2. Crazy math maze work sheet 2 UK

CRAZY MATHS MAZE WORKSHEET ANSWER

PDF file: 3. Crazy math maze work sheet ANS UK