## 6. EDIBLE CUBE

February 5, 2016

Now mathspiggies you may not want to do this in the maths classroom, but you could set this exercise as a homework project. Make it a general challenge.

eg. Homework Challenge: Make a cube out of edible products and photograph results.

You will find out how to make a Fruit Salad Cube

on WikiHow … Do you need instructions?

Rubik’s Cube Birthday Cake

for Sweet 16

You have to lerv a BORG CUBE CAKE.

It’s got lights and everything!

RESISTANCE IS FUTILE!

You can grow fruit and some vegetables in square containers,

but this project would take a very, very long time!

This is a Wonka Gobstopper Cube by Candydood.

You can work out how many gobstoppers it took to make the cube.

Yeah! 10x10x10!  That stops a lot of gobs.

I’m not sure if you can eat it. I suspect

glue may be the secret of success here.

## Maths Mystery Box 8: JUNK FOOD

February 16, 2015

Middle School Maths Challenge

Make a 3D graph or Make Like a Pringle

Pringles are mathematically yummy because each Pringle is a little 3D graph called a Hyperbolic Paraboloid or – YeeHa! – it’s a saddle.. You will find information about Hyperbolic Paraboloid at the fab Math Jokes 4 Mathy Folks blog  here and here.

You may have drawn 2D graphs. Bar graphs, Pie Charts and Linear Graphs.

A linear graph will have the equation

y = mx + c

You might have looked at quadratic equations such as the parabola:

Y = ax2 + bx + c

So what could a 3D graph of a saddle look like? Well, you have to add a z so that you have an x-axis, y-axis and a z-axis.

# The BIG challenge

Can you make a hyperbolic paraboloid? The most mathematically amazing feature of the hyperbolic paraboloid is that it can be constructed from straight lines.

Here’s How:

### 1. Cardboard and wool:

You need:

* cereal box

*wool

*ruler & scissors.

Instructions:

Cut a 15cm x 15 cm  square out of the cereal box.

Fold it diagonally.

Cut slots at 1cm interval.

Thread wool into opposite slots as shown (below).

NB: The thread should be a straight line.

Detailed instructions here.

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### 2. Wooden skewers

You will find full instructions at the Mathscraft blog.

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### 3. Cardboard only

Here is another way to make a hyperbolic paraboloid using cardboard. You will find full instructions including a video at Mathscraft.

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# 4. Bubble

You will find more about the geometry of soap films here.

More intriguing information about all sorts of geometric bubbles here at The Wonderful World of Soap Bubbles.

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## The Hyperbolic Paraboloid in Construction

The structure is often used today for rooves.