You will need
What to do
- Rule a straight line on a small sheet of cardboard. Make a mark near the middle of the line.
- Put your protractor on the line, centred on the mark. Make a second mark at an angle of 137.5 degrees. Then use your ruler to connect the marks.
- Cut along the two lines to get a piece of cardboard with a 137.5 degree angle.
- On your sheet of paper, draw a small circle to be the centre of your flower. Draw a dot in the centre of the circle.
- Draw one petal coming out of the circle. Put a small mark at the centre of the petal.
- Take your 137.5 degree angle card. Line up the angle with the centre of the circle and one of the two straight lines with the centre of your petal. Make a mark on the paper on the other straight line.
- Move the card out of the way and draw another petal for your flower, keeping it centred on the mark you just made.
- To draw the next petal, line up the 137.5 degree angle with the centre of the flower and the centre of the second petal. Draw another mark to be the centre of the next petal. Then move the angle out of the way and draw the petal.
- Keep repeating this procedure until your flower has enough petals.
It’s not easy being a plant. They can’t move, can’t see, and don’t even have a brain. Yet there are lots of actions a plant has to take. Where should the next leaf go on a branch, or the next petal on a flower? The best answer is often ‘in the biggest gap’.
One strategy to find the gaps is to grow the next leaf at a certain angle from the last one. This is relatively easy to do – it doesn’t require eyes or muscles. But it doesn’t always work. Some angles are better for a flower than others.
For example, a branch with a 180 degree angle between each leaf doesn’t do too well, because the third leaf is directly under (or over) the first. On a branch with a five degree angle between leaves, they all end up crowded together while there’s heaps of space on the far side of the branch.
It turns out that the best angle is close to 137.5 degrees. This spreads leaves out evenly, making sure they can all get sunlight. This angle can also be seen in the growth of large flowers and pinecones, and even in fancy broccoli!
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