## Happy Valentine’s Day Graph

February 14, 2020

The New York Times (The Perfect Valentine? A math formula 14 FEB 2019) has published an interactive widget from my favourite math website IMAGINARY for Valentine’s Day.

Here is the formula:

You’ll find IMAGINARY’S  interactive LOVE widget HERE.

## Math Nerd Love

February 14, 2019

The New York Times (The Perfect Valentine? A math formula 14 FEB 2019) has published an interactive widget from my favourite math website IMAGINARY for Valentine’s Day.

Here is the formula:

You’ll find IMAGINARY’S  interactive LOVE widget 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.