# Spooky Maths Magic

### Requirements; Smart board/data projector.

### This is mental maths, but not hard maths. You can play this video by Marco Frezza directly to the class.

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I started my maths workshop in Hamburg by stirring up some friendly rivalry. And what better way to do this than by using statistics.

Australia is 21.5 times the area of Germany. So I counted off 22 workshop participants and pointed to one saying ‘Your’re Germany! Ha!’ Here’s another way to compare areas:

Germany has 3.5 times the population of Australia.

But the really interesting questions are:

Who drinks more beer?

Who eats more meat?

Here are the answers to these and other interesting questions from the introduction to my workshop with apologies to Brisbane and Perth:

**One reason why students think maths is a waste of time is because they do not see it in their world. It’s not just middle school students. We are all maths blind.**

**Here is the challenge. At the beginning of your next maths class:**

**Ask your students what ‘mathsy’ thing they have on them and see what happens. Mathspig started her ICME 13 Workshop with that question and maths teachers from around the world struggled to answer. Here is what happened.**

**More ideas below.**

**Note: I missed the significance of ‘Standing on the Shoulders of Giants’ Quote. It was from the great mathematician Sir Isaac Newton, 1776.**

**More Maths on or around you: **

***food snacks: nutrition information, calories, cost.**

***medication: recommended dose, concentration eg. 5 mg, quantity, cost.**

***room temperature: weather forecast.**

***Light Bulbs: Watts, brightness (lumens, inverse quadratic function)**

***Flooring: Wood (parallel lines), carpet (tessellations), coefficient of friction (Don’t want people to slip in the wet).**

***Windows, doors: Hinges (Fulcrum, Effort as a Hyperbolic function), opening/closing door is an equation of a circle, angles, fly screens (pattern), windows (pulleys sometimes), handles (knob or lever impacts on effort)**

**Table/desk/chair: Based on statistics to fit majority of students.**

**Leaning back on chair: Centre of Gravity. Watch out. **

**Sharpening pencil: Circular motion, sharpness of blade reduces force needed. Why?**

**Pens, books dropping on floor: Good old gravity. Works every time. Quadratic fn.**

**Fonts: Size. Based on statistics for readability. Watch the small print.**

**Jewellery: Geometric shapes & patterns, but also symmetry of diamond facets, weight of diamonds in carats, purity of gold in carats (different carat).**

**Zips: Interlocking pattern hopefully not interlocking with your skin.**

**Heating: Flow rate, cost, vent locations.**

**Architecture: Of building involves length, height, area and cost. **

**External Noise: Wall thickness. Sound proofing.**

**Rubbish: Recycling. Why do it?**

**Tights: You buy them using a height weight graph on the back of the packet. **

**Here is a fabulous idea for prompting students to ‘see’ maths in the world. This activity was designed by Axelle Person Faughn, North Carolina University (Below).**

**The idea is simple. **

**Ask students to take pictures of maths they see in their lives. The photos below were taken by Axelle’s students.**

**Alternatively, you can give students an equation and ask them to find a picture representing that equation. Axelle gave Mathspig a slip of paper with the words ‘Demonstrate limits’. I sent back a picture of curly hair and a link to the equation of a helix.**

……………………………..

**Is that pasta really a Sine Curve?**

**Maths involved: **

***length of xylphone keys. These will be accurately measured to produce the correct note. Ditto width and thickness.**

***rate of rotation of gears, wheels**

***parabolic path of marble falling on xylophone keys**

***ratios of gear wheels**

***statistics. The marbles do not always bounce indentically off the keys. So the cup needs to be big enough to capture – what?- 99.99% of the bouncing marbles. I think less. You can count the number of marbles – ball bearings – that have escaped. You can see them on the floor at the end of the video. So you can calculate the % that escape.**

***timing (Each element of the machine has to be timed to create the musical effect. Not chaos.)**

***Engineering Maths: Strength of laminate. This will have been tested by the manufacturer. Laminates have a much greater tensile strength than one piece of wood. **

***Computer Cutting: A program exists to accurately cut out those wheels from a laminate.**

***Cost**

***How do you buy 2,000 marbles (ball bearings)? Do you count them? You would buy them by weight.**

***Any more suggestions?**

“Have you ever seen anything quite as pathetic?” said Malfoy. “And he’s supposed to be our teacher!”

Harry and Ron both made furious moves toward Malfoy, but Hermione got there first – SMACK!

She had slapped Malfoy across the face with all the strength she could muster. Malfoy staggered. Harry, Ron, Crabbe, and Goyle stood flabbergasted as Hermione raised her hand again.

“Don’t you *dare* call Hagrid pathetic you foul—you evil—”

“Hermione!” said Ron weakly and he tried to grab her hand as she swung it back.

“Get *off* Ron!”

Hermione pulled out her wand. Malfoy stepped backward. Crabbe and Goyle looked at him for instructions, thoroughly bewildered.

“C’mon,” Malfoy muttered, and in a moment, all three of them had disappeared into the passageway to the dungeons.

“*Hermione*!” Ron said again, sounding both stunned and impressed.”

,

**We need to talk it up. Spark their curiosity. Cafes, churches and libraries use chalkboards, billboards and prominent signs to get passersby thinking.**

**Why not maths?**

**Use a sandwich –style chalkboard ( if you are in a school where such a board wouldn’t be pinched or vandalised) or use a chalkboard or whiteboard in the maths room.**

**I’m the ****Maths Guru. ****Most people pick … Shhhh! …** seven.

**According to Alex Bellos, Favourite Number Survey, (The Observer, 12 Apr 2014) when asked to pick a number between 1 and 10 most people pick seven. This has a lot to do with our idea of randomness. One and ten do not seem random enough, nor do even numbers. This leaves three, five and seven as our choices. Forget nine. (Ooops! I did. You will too unless you have nine dogs or nine ex-wives/husbands or the like.) Five is in the middle and therefore does not seem random. We are left with two numbers and seven feels more random than three. According to Bellos**

**Try it out!!!**

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