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    Homework club: why do flower petals follow the Fibonacci sequence?

    14 April 2020

    We’re in the middle of the Easter holidays for most schools. But, as the whole point of the Homework Club is to show you that the best learning doesn’t feel like learning, the material is our usual mix of (we hope) jaw-droppers and smile-inducers. And as people seemed to like the Eiffel Tower fact a couple of weeks ago, we’re returning to the tower in Science and Nature …


    The following sentence contains seven different ways of spelling the sound ‘ee’:

    ‘He believed Caesar could see people seizing the seas.’

    So if anyone ever tries telling you that you should spell or pronounce a particular word in a particular way because that’s how another word is spelled or pronounced, use this sentence to remind them that the English language is gloriously illogical.


    The ‘Fibonacci’ sequence is a list where each number is the sum of the previous two. It starts 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144 … Can you work out the next few numbers?

    The sequence is named after the Italian mathematician Fibonacci (also known as Leonardo of Pisa), who wrote about it in 1202. It’s been shown to have uses in computing, for instance in programs that can predict the behaviour of financial markets. But it also occurs in nature – the number of petals on a flower, for instance, is very often a Fibonnaci number. Lilies have three, rose hips five, cosmea eight, some daisies 13, chicory 21 and so on. We’re not entirely sure why this should be, but one theory is that such a growth pattern maximises the amount of light received by each petal.


    The last attempted invasion of mainland Britain was in 1797, when French troops landed at Fishguard in Wales. Seeing the red shawls of the local women, the French mistakenly thought they were the British army’s Redcoats. They promptly turned around and fled.


     Istanbul is the only city in the world that straddles two continents.


    Beethoven’s Fifth Symphony was used as the call-sign for the BBC’s ‘V for Victory’ campaign during World War II, because the opening – ‘dah-dah-dah-DAAAH’ (three dots and a dash) – is Morse code for ‘V’.

    Science and Nature

    In the first Homework Club we learned about the Eiffel Tower growing in summer (because heated metal expands). But if you were to melt the tower down completely (you’d need a very big blowtorch), and then poured the metal into a square mold that was as big as the base of the tower, how high up the mold would the metal go?

    The answer is just 2.46 inches.

    Did you guess much higher than this? Don’t worry – most people do. Have a look at a picture of the tower, and try to work out why the answer is surprisingly low.

    The Eiffel Tower, Paris