# How to measure and count your sunflowers

• a waterproof pen (in case it rains)
• some tape to label each of your sunflowers
• some string
• a tape measure - at least 2-3 meters
• an adult to help out
• a digital camera or cameraphone
• a video camera to record your video diary for this stage

Other things that might help...

• our counting guide to show you what to count and to write your data on
• the seed name (cultivar) that you grew (check the seed packet) - don't worry if you can't remember the name

## Step by step guide

The important data we want you to submit are:

• the spiral counts in both directions (clockwise & anti-clockwise)

All the other data that you submit is a bonus

• number of petals
• number of bracts
• height of sunflower
• leaf data

Watch Marieke show you how to collect the data we need to make your sunflowers count towards the experiment.

### How to harvest and measure your sunflower

• If you have more than one sunflower, label it so you know which one's which
• Measure the height of your sunflower in centimetres by measuring from the middle of the head to the soil where the roots begin
• Measure the width of the sunflower head in centimetres
• Use scissors to cut off the seed head about 5cm down from the top of the stem (get an adult to help with a ladder if needed)

### How to count the spirals in the sunflower seed head

• Have a look at the diagrams on the right
• Use a camera to take a good picture of the sunflower head with the spiral patterns clearly in focus. You will need to upload this later.
• Either print out the picture to mark on the spiral patterns with a pen or use tweezers to pick out a line of seeds from every tenth spiral.
• Count the spirals in both directions - did you get Fibonacci numbers? (0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144...)
• Add the two spiral counts together - is this a Fibonacci number too?
• If you didn't get a Fibonacci number, don't worry it's still important for us to know what you get.

Once you have collected your data, register your sunflowers to submit the data.