## Wednesday 25 February 2015

### Science: make a simple kite

This kite is much more simple than the sled kite design, I worked on with my girls nearly a couple of years ago now - it also involves less complicated maths; it is a great kite for younger children to make.

It still flies we'll just more like 10 - 15 metres high as oppose to the sled kite that I believe reached 100m when my eldest, now 12 years old, made hers a year or so ago!

This is what you will need for this project:

• 2 A4 sheets of paper
• 1 drinking draw
• A ball of wool or string
• A 30cm ruler
• A pencil
• A hole punch
• Sticky tape
• Optional pens and stickers to decorate the kite

How to make a simple paper kite...

STEP ONE

Decorate your piece of A4 paper on one or both sides. This is optional but fun.

STEP TWO

Fold your A4 piece of paper in half. If you only decorate one side fold the paper so you have it blank side out.

STEP THREE

When the paper is folded, measure an inch from the top right corner, then an inch from the bottom right hand corner.

STEP FOUR

Using a 30cm ruler draw a line from one mark to the other.

STEP FIVE

Using the ruler as a guide fold down the line you made.

STEP SIX

Open it out so it looks like this...

STEP SEVEN

Using the ruler line up from one corner to the next as in photo...

STEP EIGHT

Draw a dot about 1cm from the edge of the centre fold where the ruler lies...

STEP NINE

Using a hole punch, make a hole where you drew the dot in STEP EIGHT.

STEP TEN

Cut three or four strips length ways from another A4 piece of paper that's 3 cm thick.

Decorate them if you like!

STEP ELEVEN

Using sticky tape attach the thin strips of paper together and then stick them to the base of your kite like this...

STEP TWELVE

Using the sticky tape again, fix the straw on the kite from one corner to the other, do not stick it down in the centre of the straw, just either end of the straw.  Like this...

STEP THIRTEEN

Through the hole you made in STEP NINE, attach your string with a double knot.

How it works...

As someone runs with a kite, the wind going head-on into the kite causes a lift force on it. This force is vertically straight to the wind, pushing the kite up. At the same time, the force of drag pulls the kite back in the direction that the wind is going and that is what makes your kite take off!

A kite is affected by thrust, drag and by gravity.

Drag is made by wind resistance on the kites surface (the sail and tail) and can also be the caused by turbulence from behind the kite.

Gravity is the downward force that is created by the weight of the kite.

and

Thrust is the power of the wind that creates lift.

For a kite to fly you need to have...

Enough lift to overcome gravity and drag. Lift, drag, gravity and thrust come together when flying a kite to a central point called the centre of pressure.  The centre of pressure is where we tie the flight string and is called the tow point.

To learn more about how a kite works, go to my post: How does a kite fly?

For the older children or those who wish to be challenged more there is a link here to my sled kite design that flies super high if you're careful when making it. How it works can be found in my post: How does a kite fly?