Archive for the ‘Decimals’ Category

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

July 25, 2022

mathspig-smoke-jumpers  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

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

mathspig-firefighter-maths-2

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

mathspig-fire-fighter-table-2

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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How Gamers Gamed the Hedge Funds: Middle School Math

January 28, 2022

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22 Amazing Numbers for 2022  … Answers Q 11 – 16

January 6, 2022

Ref: (bbc.com)

Ref: Dermatology Clinic

REf:(time.com)

Ref: Call of Duty

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I Can’t Sleep: Caffeine Math Part 3 USA UNITS

November 13, 2021

I Can’t Sleep Math: Caffeine Maths METRIC HERE.

Sensitivity to caffeine varies for individuals, but in healthy adults the half life for caffeine is approx 6hrs meaning your body eliminates half the caffeine you have drunk in 6 hrs. Ref: Caffeine Pharmacology

Caffeine interferes with sleep. One study found that consuming caffeine 6 hours before bedtime reduced total sleep time by 1 hour.

Caffeine content sources Caffeine Content Data Base

Street art by JEKS, South Carolina

The Half life equation is an exponential function.

The Mayo Clinic advises up to 400mg Caffeine a day for adults, which would be;

10 black teas

7 instant coffees

4 cappuccinos

2 dark roast brewed

less than one cup of Black Insomnia Coffee.

Approx half this amount of caffeine for 14 yos.

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Halloween Math: IT Chapter 2 vs Kill Bill Vol 2 in Fake Blood

October 15, 2021

Halloween Blood can be found @ Party City

Stage blood @ Stage MakeupMovie Blood @ Thomasfx

*Note: These were the fake blood volumes quoted 12 years ago when I was first researching fake blood data. I have noticed the numbers on various chat platforms have inflated  the volumes in the last 12 years.

*Note: Rounding off the initial volume eg. 0.06 pint (0.028L) then up-scaling that volume to 36,000 pints (17,000L) introduces a significant error in the final calculations.

 

 

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Car Crash Maths: Saved by a millisecond

August 22, 2021

*In 1970 the Victorian Government made the wearing of seat belts compulsory.

*The first government in the west to do so.

 *Within 14 months the other Australian states followed.

*The road toll in Australia dropped:

   1969       3,382 road deaths per year

   1988       2,887 deaths

   2018      1,135  deaths

Mathspig lived on a country police station before seat belts became compulsory and a number of kids she went to school with died in car accidents.

Three factors have reduced the road toll in Australia:

1. Wearing seat belts

2. Stopping drink driving

3. Introducing Airbags (from 1980s)

Our eyes can easily detect the blink (above) set a 300ms.

Ditto, the light flash (below), which is set to flash at  200 ms but it will drive you CRAZY if you look at it for too long.

The fabulous video (below) will show you the amazing details of the ms timing that saves lives in a car crash. You will see real car crash tests. And the frightening results too.

It was made by an engineer who worked for GMH or Holden as we call it in Australia. 

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20 Gobsmacklingly AMAZING numbers … Revisited

May 25, 2021

… these nos. are  amaaaazing but no one could find the answers in the earlier post.

………………………………………………………..

Click on the POP-UP answers under each question.

1. How many bristles in a toothbrush?

2. What % of Oxygen in the atmosphere comes from forests?

3. How loud was the loudest recorded human scream?

4. How many apples could kill an average-sized adult?

5. How many countries in Africa?

6. What happens when you Google this number, 241543903?

7. How many vertebrae in a giraffe’s neck?

8. What is the highest recorded wind speed?

9. What is the world record high-jump height for a guinea pig?

10. How many times does England fit into Australia?

11. How much did the most expensive dessert ever cost?

12. Why is 70 a weird number?

13. Why Google Googol?

14. How many burgers does McDonalds sell a second worldwide?

15. If the population of the world was spread evenly across the USA, what area would we get each in basketball court sections?

16. How many times was the most frequently married person in the world, married?

17. Why is Zero Zero Zero like 123?

18. What is the world record for the greatest number of snorts in 10 seconds?

19. How long would it take to grow your hair to your feet?

20. What number causes the greatest loss of money in the world?

LINKS:

1. How many bristles in a toothbrush? HERE

2. What % of Oxygen in the atmosphere comes from forests? HERE

3. 3. How loud was the loudest recorded human scream? GOOGLE IT!

4. How many apples could kill an average-sized adult? HERE

5. 5. How many countries in Africa? GOOGLE IT!

6. What happens when you Google this number: 241543903? HERE

7. How many vertebrae in a giraffe’s neck? HERE

8. What is the highest recorded wind speed? HERE and HERE

9. What is the world record high-jump height for a guinea pig? GOOGLE IT!

10. How many times does England fit into Australia? GOOGLE IT!

11. How much did the most expensive dessert ever cost? GOOGLE AGAIN.

12. Why is 70 a weird number? HERE

13. Why Google Googol? HERE

14. How many burgers does McDonalds sell a second worldwide? HERE

15. If the population of the world spread across the USA , what area would we get each?

GOOGLE THE NUMBERS!

16. How many times was the most frequently married person in the world, married?

GOOGLE HIM.

17. Why is Zero Zero Zero like 123? HERE

18. What is the world record for the greatest number of snorts in 10 seconds? HERE

19. How long would it take to grow your hair to your feet? HERE

20. 20. What number causes the greatest loss of money in the world? HERE

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20 AMAZING numbers

April 26, 2021

… so amaaaazing you’ll have to check them for yourself!

POP UP ANSWERS … click on Q.

1. How many bristles in a toothbrush?

2. What % of Oxygen in the atmosphere comes from forests?

3. How loud was the loudest recorded human scream?

4. How many apples could kill an average-sized adult?

5. How many countries in Africa?

6. What happens when you Google this number, 241543903?

7. How many vertebrae in a giraffe’s neck

8. What is the highest recorded wind speed?

9. What is the world record high-jump height for a guinea pig?

10. How many times does England fit into Australia?

11. How much did the most expensive dessert ever cost?

12. Why is 70 a weird number?

13. Why Google Googol?

14. How many burgers does McDonalds sell a second worldwide?

15. If the population of the world was spread evenly across the USA, what area would we get each in basketball court sections?

16. How many times was the most frequently married person in the world, married?

17. Why is Zero Zero Zero like 123?

18. What is the world record for the greatest number of snorts in 10 seconds?

19. How long would it take to grow your hair to your feet?

20. What number causes the greatest loss of money in the world?

LINKS:

1. How many bristles in a toothbrush? HERE

2. What % of Oxygen in the atmosphere comes from forests? HERE

3. 3. How loud was the loudest recorded human scream? GOOGLE IT!

4. How many apples could kill an average-sized adult? HERE

5. 5. How many countries in Africa? GOOGLE IT!

6. What happens when you Google this number: 241543903? HERE

7. How many vertebrae in a giraffe’s neck? HERE

8. What is the highest recorded wind speed? HERE and HERE

9. What is the world record high-jump height for a guinea pig? GOOGLE IT!

10. How many times does England fit into Australia? GOOGLE IT!

11. How much did the most expensive dessert ever cost? GOOGLE AGAIN.

12. Why is 70 a weird number? HERE

13. Why Google Googol? HERE

14. How many burgers does McDonalds sell a second worldwide? HERE

15. If the population of the world spread across the USA , what area would we get each?

GOOGLE THE NUMBERS!

16. How many times was the most frequently married person in the world, married?

GOOGLE HIM.

17. Why is Zero Zero Zero like 123? HERE

18. What is the world record for the greatest number of snorts in 10 seconds? HERE

19. How long would it take to grow your hair to your feet? HERE

20. 20. What number causes the greatest loss of money in the world? HERE

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Ohtani vs The World ………………………. Some amazing fastball facts.

April 12, 2021

More Info: New York Times, 5 April 2021

Also: Which sport is more DANGEROUS to play? Cricket or baseball?

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Death by Chocolate: Yes! Chocolate can kill. But how much would kill you?

February 24, 2021

 Choco Yum Yum! Mathspig lervs chocolate. But did you know chocolate can kill you?

Chocolate contains a chemical called Theobromine. This alkaloid ( other alkaloids include cocaine, nicotine, caffeine, and strychnine) can kill humans. More info Wired Magazine.

How much chocolate is too much?

Firstly, the darker the chocolate the more Theobromine it contains.

According to About Chemistry based on the highest possible toxicity:

* VetmedicineCooking chocolate contains 8-10 times the Theobromine in Milk Chocolate.

According to Wired large doses of theobromine may cause “nausea and anorexia ….. sweating, trembling and severe headache.”

The Royal Society of Chemistry notes that chocolate does not contain caffeine, but theobromine induces similar symptoms.

LD50 for the lethal dose for 50% of the population for Theobromine is:

1000 mg/kg 0r 1gm/kg of body weight in humans

Death by Chocolate Calculations:

1. FORMULA

Mathspig Death by Chocolate Formula

2. GRAPH

Mathspig Death by Choc Graph

3. Percentage

Mathspig Death by Chocolate  % Method