Site Visits

Tuesday, December 24, 2013

Rabbits Galore!

Photo credit:
This is the image I posted in the last entry. Now I want to go through it with you so you can see how exactly this pattern leads to the Fibonacci sequence.

Recall that the premise of Fibonacci's question was this:

1. You begin with one male rabbit and one female rabbit. These rabbits have just been born.
2. A rabbit will reach sexual maturity after one month.
3. The gestation period of a rabbit is one month.
4. Once it has reached sexual maturity, a female rabbit will give birth every month.
5. A female rabbit will always give birth to one male rabbit and one female rabbit.
6. Rabbits never die.

Ok, some of these may be a bit of a stretch, but let's just go with it. What do we have in Month #0 (the very start)?

Month 0: There is ONE pair of rabbits.

Month 1: The two rabbits have mated, but are not yet ready to give birth. Therefore, there is still just the ONE pair.

Month 2: Babies! But note Rule #5 - the female always gives birth to a pair of rabbits, so now we have TWO pairs.

Month 3: The original pair gives birth again (see #4), but the newest pair is now only able to mate. They will need to wait one more month before giving birth. So now we have THREE pairs.

Month 4: Finally, BOTH pairs of rabbits give birth and we now have FIVE pairs.

Month 5: Here is where it gets a little tricky, but by now, we have three pairs that are able to give birth and do so, leaving us with a total of EIGHT pairs of rabbits.

1, 1, 2, 3, 5, 8.... So develops the Fibonacci sequence. In my next post, we'll look at honeybees, and how they build their colonies. The process is quite different, but a) the result is the same, and b) unlike these hypothetical rabbits, the bees are real.

Sunday, December 15, 2013

Who was this Fibonacci guy anyway?

Leonard Pisano (1170-1250),
also known as Fibonacci.
Photo credit:

You may already know of a famous Italian named Leonardo. He was an artist, inventor, mathematician, scientist, and more. Leonardo was from a town called Vinci in the Tuscany region. For that reason, we commonly know him as Leonardo da Vinci, or Leonardo from Vinci.

However, you may not know about the other famous Leonardo, who was also from Tuscany. You see, he was born and, later in life, lived in Pisa (the town with that leaning tower). So he was originally known as Leonardo Pisano (as in 'Leonardo, the guy from Pisa'). He also went by the name Leonardo Bigollo (wanderer, good-for-nothing).

But you see, as a child, Leonardo was not as well known as his father, Guglielmo Bonacci. Bonacci was a diplomat who represented Pisa in business dealings in North Africa. Leonardo was trained in accounting by African teachers, and didn't return to Pisa until he was around 30 years of age.

In Italian, the word 'figlio' (FEEL-yo) means 'son'. So Leonardo, who was the son of Bonacci, was known as "Figlio di Bonacci", the son of Bonacci. Over time, it shortened down to Fibonacci.

Fibonacci's most famous work was the Liber Abaci, or The Book of Calculation. In that book, he posed the following question:

A certain man put a pair of rabbits in a place surrounded on all sides by a wall. How many pairs of rabbits can be produced from that pair in a year if it is supposed that every month each pair begets a new pair which from the second month on becomes productive?

One can see that this problem elicits the sequence 1, 1, 2, 3, 5, 8 ,13, 21, 34, .... 

The Fibonacci Sequence as seen in a
growing rabbit population.
Photo Credit:

I doubt old Leonardo could have predicted just how many places his numbers would turn up over the next 800 years. Over the next several posts, I will be exploring the unusual, the unexpected, and the truly unbelievable places you might run into a Fibonacci number. We will be looking at the fields of botany, zoology, marine biology, design, architecture, and even the stock market.

Stay tuned.

Saturday, December 7, 2013

Welcome to Author Tom Robinson's Blog!

1, 1, 2, 3, 5, 8, 13, 21, 34, .... ?

Welcome to my author blog! This is my first entry and tonight I am celebrating the signing of my latest contract. 

Coming soon to a bookstore near you : Fibonacci Zoo, from Arbordale Publishing.

In this blog, I will be discussing the MANY different examples and applications of Fibonacci numbers, a little of the history behind the sequence, and even a little bit about Fibonacci himself. 

The Fibonacci numbers are made according to a very simple rule. Start with the numbers 1 and 1 (some versions start with 0, but my book will begin with 1, because a zoo with zero animals in it just isn't that interesting!) and then form the next number by ADDING up the two previous numbers. 

So after 1 and 1, the next number will be 1+1 =2. After that, 1+2 = 3, 2+3 = 5, and so on!

Over the next several months, I will be posting examples for YOU to see Fibonacci numbers in action. You will find them in the fields of botany, zoology and marine biology, and in the careers of graphics, design, and architecture. 

For now, however, I want to simply say a big thank you to Katie Hall,  my editor at Sylvan Dell, and to encourage you to check out my other books currently for sale:

Everything Kids Science Experiments Book - #61 on Amazon's Best Seller List, as of December 7, 2013