On how creativity works there is an anecdote of **Sir Ernest Rutherford**, president of the British Royal Society and Nobel Prize in Chemistry in 1908, told the following:

Some time ago, I received a call from a colleague. He was about to zero a student for the answer he had given in a physics problem, even though he firmly stated that his answer was absolutely correct.

Teachers and students agreed to request arbitration from someone impartial and I was elected.

I read the exam question and it said:

- Show how it is possible to determine the height of a building with the help of a barometer.

The student had responded: the barometer is taken to the roof of the building and a very long rope is attached. It is lifted to the base of the building, the rope is marked when the barometer reaches the ground and is measured. The length of the rope is equal to the length of the building.

Actually, the student had posed a serious problem with the resolution of the exercise, because he had answered the question correctly and completely.

On the other hand, if he was awarded the highest score, he could alter the average of his year of studies: if he obtained a high grade, it would certify his high level in physics, but the answer did not confirm that the student had that level.

I suggested that the student be given another opportunity. I gave him six minutes to answer the same question but this time with the warning that he should demonstrate his knowledge of physics in the answer.

Five minutes had passed and the student had not written anything. I asked him if he wanted to leave, but he said he had many answers to the problem. His difficulty was to choose the best one.

I excused myself for interrupting him and begged him to continue.

In the minute he had left he wrote the following response: The barometer is taken and thrown to the ground from the roof of the building, the fall time is calculated with a stopwatch. Then the formula h = 2gt2 is applied, so we obtain the height of the building.

At this point I asked my colleague if the student could withdraw. He gave the highest grade.

After leaving the office, I met the student again and asked him to tell me his other answers to the question.

Well, he replied, there are many ways, for example, you take the barometer on a sunny day and measure the height of the barometer and the length of its shadow. If we then measure the length of the shadow of the building and apply a simple proportion, we will also obtain the height of the building.

- Perfect, I said, and in another way?
- Yes, I answer: this is a very basic procedure to measure the height of a building, but it also works. In this method, the barometer is taken and placed on the stairs of the building on the ground floor. As you go up the stairs, the height of the barometer is marked and the number of marks to the roof is counted. Upon arrival, the height of the barometer is multiplied by the number of marks and this result is the height. This is a very direct method.
- Of course, if what you want is a more sophisticated procedure, you can tie the barometer to a rope and move it as if it were a pendulum. If we calculate that when the barometer is at the height of the roof the gravity is zero and if we take into account the measure of the acceleration of gravity when the barometer descends in a circular path when passing through the perpendicular of the building, of the difference of these values, and applying a simple trigonometric formula, we could calculate, without a doubt, the height of the building.
- In this same style of system, you tie the barometer to a rope and pick it up from the roof to the street. Using it as a pendulum you can calculate the height by measuring its precession period.
- In short, I conclude, there are many other ways. Probably, it is best to take the barometer and knock the door of the janitor's house with it. When you open, say: Mr. Concierge, here I have a nice barometer. If you tell me the height of this building, I give it to you.

At this time in the conversation, I asked him if he did not know the conventional answer to the problem (the pressure difference marked by a barometer in two different places gives us the height difference between both places) evidently, he said he knew her, but that during his studies, his teachers had tried to teach him to think.

The student's name was **Niels Bor, Danish physicist, Nobel Prize in Physics in 1922**, best known for being the first to propose the atom model with protons and neutrons and the electrons that surrounded it. He was fundamentally an innovator of quantum theory.