Written by: Newton C. Braga

 

The technological discussions of Professor Ventura, Bart and Bert have always been very interesting and, eventually, heated. Taking into account the principles of physics and the availability of real resources, it was never something that did not have a solid scientific basis and that could eventually be explored by science and technology. This time, however, it seems that the discussion had gone too far:

 

- Yes, I say we can store energy in just about anything. - Professor Ventura insisted, in front of his two students, sitting on the old sofa in the corner of the laboratory. - A contracted spring, the electric field between the plates of a supercapacitor, a dam containing a large amount of water and even a hole. It all depends on knowing how to handle the energy.

 

Bart was startled by the answer.

 

- A black hole, you mean.

 

The teacher was unmoved.

 

- No, a common hole. The ones we make with a spade and a hoe.

Bert, who until then just watched, was startled.

 

- Impossible! How to save energy in a hole. We will contract the emptiness like a spring so that it acquires energy... - Bart continued:

 

- And then make the hole expand to release the energy. Negative energy, certainly.

 

The teacher, who waited for the completion of the two students, continued.

 

- You know that I don't say things that don't have a scientific basis. What I am saying is quite possible. We can store energy in a hole, and we don't need much to do that as well as to recover the stored energy. Going further, I think it is something to be explored.

 

Incredulous, the two students once again questioned the old professor:

 

- Impossible! How can one store energy in a hole? It has no scientific basis.

 

Realizing that the students were not believing his words, he made an interesting proposal:

 

- Let's bet! I bet a round of ice cream in the parlor from the square that it is possible to store energy in a hole, without violating any principle of physics, especially the conservation of energy.

 

- The bet is on! Now… explain.

 

The teacher raised his hands and added:

 

- Easy, I will not give you the chance to have the solution now. I want to see you using your brains to prove me wrong. I'm going to give you some time to think about how to do this. Let's agree! Today is Monday. You have until Saturday to think about it and imagine a solution. After all, you are makers, and a maker must be prepared to solve the most complicated challenges of technology (and science).

 

Bart and Bert realized that they shouldn't have challenged the professor.

 

- If I am not presented with a solution to the problem and I can prove that it is possible to “save” energy in a hole, you pay two rounds of ice cream. If I am presented with a consistent solution, I pay one round, and if I do not present a consistent solution, I am the one who pays two rounds of ice cream.

 

- Done!

 

The bet was made. They agreed that on Saturday they should meet in the teacher's lab, at the Technical School, and he should explain how his “energy storage in a hole” system would work.

 

- Burying a few bottles of “energy drink”. - Imagined Bert, in a last attempt to think how it could be done.

 

The rules were simple: it should have scientific consistency and be totally feasible to build without exorbitant cost, with the technology available today. Energy would not necessarily have to be electric, as none of the shapes we have today do that. Batteries store energy by transferring it to chemicals, capacitors store it in the form of electric fields and springs, store mechanical energy when contracted. Holes, store energy in the form ... Well, that was what the teacher should explain.

 

On the way home, Bart and Bert were already starting to discuss the problem.

 

- It is true that the teacher has a lot of imagination, but I think he went too far. How can one store energy in a hole? - Bert did not believe in a solution.

 

- Contracting a hole by applying energy and then recovering it with its expansion? Taking advantage of the difference in energy between an empty and a full hole? No! If it were a black hole, perhaps astrophysicists would have explanations. - Bart was analyzing the problem.

 

- Entropy? How to calculate the entropy of an empty hole and a full hole? - Bert, who was a good student of physics and chemistry, remembered some high school lectures.

 

- I'll take a look at my physics books. Maybe I can find some ideas there.

 

The two continued their journey together until the point where they separated, each going to their home. However, the matter continued to “hammer” in their heads. They agreed that the next day, they would return to the laboratory early to continue discussing and eventually get some information from Professor Ventura to give them a clue. What was the old professor thinking?

 

The next morning, after meeting at the usual place, the two friends went to school. They would go to the laboratory where Prof. Ventura would already be working on his experiments, preparing classes and writing his technical articles. However, it was on this path that an unexpected encounter served as a trigger for a real explosion of events which would culminate in the spread of a problem that affected not only the small city in its whole, but the state, the country and the world.

 

What happened? Certainly, in anything out of the ordinary that Professor Ventura, Bart and Bert got involved, Tubald Weathercock should be present at some point. And this is what happened.

 

(*) This is one of Professor Ventura's many adventures that I wrote. In the article NVENT000E those who do not know the characters can have a brief description of each one. Just to say, Tubald is a short, chubby man with funny features who plays the tuba in the local band. For reasons which only fate explains, he gets involved in a funny way in Professor Ventura's work. And it was not this time that he escaped.

 

On the way to school, Bart and Bert cross paths with Tubald who, carrying his tuba, was going to his “business” in the city, opening the doors of his barbershop early. He took the tuba, because after hours the band would play in the bandstand, and as always, he would be present.

 

- Good Morning! - Exclaimed the two young men.

 

- Good Morning! - Replied the musician, but something caught his attention. Bert was staring at the tuba.

 

Tubald noticed. But, without a shock he asked them both.

 

- I already know! You're going to meet Professor Ventura. What crazy novelty are you planning now? I hope it doesn't affect people.

 

Bart knew that it would not do any good going into technical details, so he “invented” a simple answer to please the musician, without going into details.

 

- Nothing much. Professor Ventura is creating a project to store energy in holes.

 

Needless to say, the musician, a barber without scientific training and technology, did not understand anything, but he was curious. Store energy in holes! Bombarded with the technological innovations brought by his clients, who discussed them while cutting their hair, it would be an interesting subject, mainly because it involved a controversial personality in the city, Prof. Ventura.

 

- Ah! Very interesting.

 

The musician went his way, as did Bart and Bert, but at one point something happened. Tubald, noticing something strange, turned around looking back.

 

Bart tried to get Bert to go their way, but he didn't move, staring intently at Tubald's tuba. The little man was startled.

 

- My tuba! It has something to do with Professor Ventura's "crazy" experiments. They know something! - The musician immediately thought.

 

He then went his way, with an interesting novelty to talk about with his customers, but on the other hand, very concerned with his tuba.

 

- Energy in holes and my tuba! There is something strange there.

 

Bart finally managed to bring Bert to the real world.

 

- What happened to you?

 

- The tuba. Something occurred to me that might have something to do with Professor Ventura's idea of storing energy in a hole.

 

Bart started:

 

- What?

 

- Yes. See that it has a huge hole through which the sound comes out, and its shape resembles a whirlwind, like that formed in a black hole. The "energies" can be concentrated there... It has to be something like that.

 

Bart interrupted his friend:

 

- You're going too far. What has a tuba to do with the hole that stores Professor Ventura's energy and the whirlwind that concentrates high energy in black holes.

 

- I don't know. But there is something there. I'll think about it.

 

What the two young boys did not know is that the conversation with Tubald would not be just between them. In a city like Lemon City, the news spreads quickly, especially when it involves strange things, local personalities and a barber who talks to everyone. That is what happened.

 

Tubald spread the word that Professor Ventura would have found a way to store energy in holes and that he would certainly get rich from it. Yes, things when they pass from mouth to mouth acquire increasing dimensions without mentioning the distortion of the facts and the distortions also occurred.

 

Some interpreted that Professor Ventura was threatening the world by bringing black holes into Lemon City. Others said he would be drilling holes throughout the city to store energy. And this idea ended up going to the mayor’s secretary who, worried, took the news to the "preboste" Saturnino, the mayor.

 

- Damn it! What is he going to do this time? We’ll prevent him from digging holes in our city, even if it’s to store energy. I’ll issue a decree banning it.

 

It was not the first time, without knowing anything about physics, let alone what was happening, the mayor tried to interfere in things in a gaudy way. It is said that once, when the city decided to build a new reservoir for water distribution, the engineers proposed that it should be installed on the top of the hill next to the city. The mayor, proud of his first great work, interfered.

 

- No! It has to stay in the square. Right in the middle of the city.

 

That was when one of the engineers explained that it was not possible:

 

- No, it can't be, it needs to stay high, because of the Law of Gravity.

 

The mayor without blinking interfered:

 

- No! It will stay in the square. If it is because of the Law of Gravity, we will revoke it.

 

Needless to say, the subject became a joke. But this time, more cautiously, he decided to go and speak directly with Professor Ventura. Given the explanations that it was just a bet and that nothing was going to be dug, no holes in the city, the mayor returned satisfied.

 

But the news had already spread. And, Tubald came home worried.

 

- My tuba! It has something to do with it all. Black holes, negative energy, nuclear explosions! Hmph!

 

Of course, really, the "explanations" given always had something increased. Whoever passes news to another person, involuntarily, always adds something of their own and the distortion grows. The old saying goes:

 

"The tale grows in the telling."

 

Tubald had a nightmare that night.

 

He dreamed that Professor Ventura “hijacked” his tuba for experiments for energy storage. In the dream, the teacher connected in his tuba two wires which came from a box and buried it in a huge hole. Two wires stuck out and, connected to a lamp, made it light.

 

He woke up screaming and sweating. His wife had to calm him down with a glass of water.

 

Bart and Bert, in Professor Ventura's laboratory, were trying to get some clue as to how energy could be stored in a hole.

 

- Give us a clue!

 

Without going into details, the professor simply said:

 

- Negative potential energy.

 

- What?

 

Unaware that their bet became very important, Bart and Bert continued to wonder how it could be done.

 

An important character in the city was very concerned. It was the psychologist Roman Bacamarte. Yes, they said that he was Simão Bacamarte's cousin, but that was soon denied, since Simão Bacamarte was a character created by Machado de Assis (Brazilian writer) in his short story “The Alienist” (O Alienista – original in Portuguese). Suddenly fiction and reality were mixed, and, in the city, nobody knew if Roman was a cousin of a virtual or real creature.

 

- But it has something to do. - Some commented

 

- Yes, his profession is very similar to Simão’s and the way he acts resembles the character of the story.

 

In fact, more than once, due to the professor’s experiments, which sometimes went wrong, he had tried to “admit” Professor Ventura to a sanatorium. This time, he was just watching.

 

Professor Ventura, Bart and Bert did not realize that the news about their “research”, that was done in their laboratory, was taking on such worrying dimensions.

 

One of Tubald's clients, with whom he had commented on the research to store energy in a hole, decided to contact some technology experts with whom he had contact over the Internet, to find out if it was really possible.

 

First it was Rudolph from the Garage Lab, who, surprised by the fact, decided to put it on his channel, drawing the attention of thousands of followers. Then came Burgos and Rambo who also commented on the matter. The result: the subject was spread around the world. Everyone wanted to know who Professor Ventura was, the one who had found a way to store energy in a hole.

 

A Russian and a Chinese hacker threatened to break into the small page that Prof. Ventura had on the Internet, hoping to get the "plans" which would certainly revolutionize the world ...

 

But the doubt persisted. How does he do that?

 

Even a specialist in 3D printers, Guilherme Razgrizz wondered how it would be possible to print a hole in 3D to store energy. Other experts were considering incorporating controls for energy stored via the internet, thus turning a hole into yet another application of the IoT. Needless to say, even the wearable specialist Gedeane thought of creating a wearable hole to provide power for applications. Where the hole would be, she did not explain. Anyway, the news spread.

 

And, it spread so widely, that Professor Ventura was approached by a multitude of experts who wanted him to reveal the secret.

 

- How can one store energy in a hole...

 

They demanded him to reveal, even though they knew it was the result of a bet, if he had the solution, he should make it public. And so it was agreed that on Saturday, the day he was supposed to show the solution to the problem, it would be done on a “live”.

 

The event had been announced. Thousands of subscribers. Many made bets. Many tried to advance the solution with the most diverse hypotheses:

 

- Mini black hole.

 

- Place a supercapacitor at the bottom of a hole.

 

- Inverting a hole to store negative energy (if that's possible, I don't know.)

 

- Fill a hole with electrons.

 

- Use na elastor inside a hole. Both are inverted things ...

 

(What is na elastor? See the answer on our website.)

 

And many other hypotheses that certainly lacked scientific basis, when there are more possibilities to be put into practice.

 

It is clear that some interesting facts occurred in the city, making the subject even more relevant. And, of course, it was precisely with Tubald that a small accident occurred in the meantime.

 

On Friday, the day before Prof. Ventura’s presentation, finishing his performance at the bandstand where the band played, Tubald returned home late at night when the unexpected happened.

 

It had rained a lot during the day, and on the way to the musician's house in a village near the center, there were puddles and some clay spots, which had slipped from the ravines. There was a lot of dirt scattered, as the city was carrying out some works in addition to the holes.

 

Holes!

 

Concerned about the holes of Prof. Ventura, Tubald did not pay much attention on his way and fell... into a hole!

 

- Wow! ...

 

In the bottom of the hole, filled with water and mud, Tubald collapsed, dirtying his clothes and filling the tuba with muddy water. At that moment, a flash and a thunderstorm of an approaching rain made the tuba resonate with a brontophonic sound. (see in our article ART400E what this is)

 

Frightened, dirty with clay, the little guy had difficulty getting out. Fortunately, he wasn't hurt. Imagining negative energies coming from the bottom of the hole that could suck him and his tuba into another dimension, turning him into energy in a Professor Ventura experiment, he ran. And how he ran!

 

- Ginevra! Help! - He shouted asking for his wife as he ran into the house.

 

Breathless, he told a story that he was "drawn" to the hole by strange forces and how he escaped being sucked into a fourth dimension...

 

His wife, already aware of his exaggerations, calmed him down.

 

The day for presenting the solution to the problem has arrived. Everyone was waiting for Professor Ventura. The online live was opened exactly at the agreed time. Bart and Bert took charge of managing the channel. A camera was placed in the laboratory pointing to a blackboard. Professor Ventura would use it in his explanations.

 

Thousands had signed up, eagerly following Prof. Ventura on his channel.

 

The signal was given, and Professor Ventura started. After thanking the audience and explaining why he was there, minimizing the consequences of the events which had spread so unexpectedly, he said it was supposed to be just a simple bet, but it had a strong scientific basis and was perfectly viable. He would explain:

 

- I’m going to try to speak in a very simple way so that everyone understands me. I will use only the concepts of physics which everyone must have learned in their middle school and eventually even in elementary. Our starting point is energy because we are just dealing with how it can be stored.

 

The professor went to the blackboard where he represented a rectangle inside which he wrote the word energy.

 

- There is no definition for energy: We say that a body or a system has energy when it has the capacity to do work. Work? What is it? It is the ability to perform a force, an action or a movement. To move a body from one location to another, we need to apply force to it. With that we spend energy, which will be given by the force we perform multiplied by the path in which we must move the object and, of course, by its mass.

 

The teacher paused.

 

- Moving on. In this case, we have mechanical energy, that is, we convert the energy available in this body into a force that has been converted into displacement. But we may have other forms of energy which are not entirely interesting at this point. We can have the energy stored in a battery in the form of chemicals that can release it in the form of electricity, by lighting a lamp, for example. The same occurs in a capacitor where we store energy in an electric field, and then we can obtain it in the form of an electric current. But, back to the mechanical energy.

 

Erasing the previous drawings on the board, the teacher drew three springs. One in a normal position, one contracted and one stretched. He explained:

 

- A spring under normal conditions cannot make any kind of effort or produce any kind of movement. It does not contain any stored energy. Right?

 

Many of those who were following the live, nodded, agreeing, even though they knew they were not being seen. The teacher continued.

 

- However, if I apply force to the spring to contract it, I am using energy for that and that energy will be stored in this spring. I can recover that energy later by having the spring deliver it by moving some kind of mechanism. Old watches and toys did that. We needed to "wind it up" for them to work. What we were doing was simply storing energy in the spring.

 

Waiting for a few seconds, the teacher continued.

 

- Of course, that the spring can deliver the energy until it returns to its normal position. Then see that we store “positive” potential energy in the spring. But then something interesting comes in:

 

Raising his finger to get attention, the teacher went to the stretched spring:

 

- To stretch a spring out of its normal position, we also need to apply force. We are also storing energy that can be harnessed when it contracts to normal. However, in physics we need to have reference when we want to measure something, that is, a quantity.

 

The teacher then pointed to the spring in the normal position:

 

- When the spring is in its normal condition, without being contracted or distended, it does not have the ability to move something, that is, to perform work. So, we say its energy is zero. As it is an energy that is given by force and not by movement, we go further and say that its potential energy is zero.

 

He continued:

 

- So, we can say that the contracted spring has positive potential energy, the value of which depends on its degree of contraction. And, that it has negative potential energy if it is distended, depending on its stretching.

 

Bart and Bert, who accompanied the professor, agreed. He continued.

 

- Now, we're getting closer to what matters. Imagine the potential energy of a body that is in a high place. If we take the floor level as zero as reference, it will have both greater energy, that is, the ability to perform work, the greater the mass and the higher it is.

 

The professor designed a slide showing an old cuckoo clock.

 

- In a watch like this, when we pull the chain and raise the weight, we are delivering potential energy to the weight. With the potential positive energy, when we pull it down it delivers this energy to the mechanism that makes the clock work. Until at the lowest level, having no more energy to deliver, the watch stops. We must again deliver energy to it by suspending it.

 

The professor went to the board where he had designed a dam.

 

- In this case, we have the potential positive energy of a dam. Water contains energy which can deliver it to a turbine that converts it to electricity when it moves to a lower level, which we take as a reference as zero. See then that we can store energy in a dam.

 

He then raised his index finger and explained:

 

- We are getting to the point: if during the day, we take solar energy captured by panels and use it to pump water into a dam. Basically, we are storing solar energy in this dam.

 

The professor, with a very serious expression, looked at the camera and asked:

 

- What if the water can drain into a hole? Will it still deliver power to a turbine?

 

Bart and Bert looked at each other.

 

- Yes, certainly! - they said and with that the Professor agreed.

 

- If we take the normal water level, for example, on a plain where we cannot have a dam. And we make a hole. When we drain water, it can deliver energy to a turbine. As its energy at the reference level is zero, when it flows, it starts to deliver its potential positive energy to the hole that decreases its negative potential energy. In short, at the bottom of the hole, we will have water with negative potential energy and as the water rises filling the hole, the energy of the hole goes up towards zero.

 

- And the turbine works!

 

Bart commented to Bert.

 

- It is different from temperature that there is no cold colder than absolute zero. Not energy, we can have it in a negative form.

 

The teacher continued:

 

- We got to the point, let's imagine now that we make a huge hole here in our city. A hole 40 meters deep and 100 x 100 m in size.

 

The teacher made a drawing illustrating what he wanted to demonstrate:

 

- At half a height, for example, 20 meters from the bottom we put a turbine that will have the water brought by a pipe from our river, which runs at the normal level. At the bottom of the hole, we will place a pipe that will be connected to pumps to empty the hole. These pumps will be driven by solar panels.

 

All of this was drawn on the blackboard. The teacher was ready to explain his idea:

 

- Let's start from the moment the hole is empty. I won't say that in reality it is full of negative potential energy, but that's it.

 

Many people who had not followed the master's reasoning did not understand, but it would become clear later.

 

- When we open the floodgates to fill the hole, the water fills it and thus moves the turbines which generate electricity, to power the city street lights at night. And the negative energy from the hole decreases as the water rises. This up to the point where it reaches the level of the turbine.

 

The teacher then showed points A and B on his drawing.

 

- This is the range of harnessing the negative energy of the hole. Above that, the water already loses its pressure as the hole fills and the use of energy begins to decrease.

 

It was becoming clearer to Bart and Bert.

 

- At this point, we already took advantage of the negative potential energy which was stored in the hole. We need to replace it by "charging" the energy hole again. Thus, it is enough that the next day the solar panels activate the pumps for emptying the hole, which then, as the water lowers, has its negative energy replaced. It becomes charged with energy again.

 

- Damn it! The teacher is right. We are storing energy in the hole - Commented Bert.

 

The teacher heard the boy and smiled.

 

- Once charged, with all its energy stored, at night just turn on the turbine to refill it to the ideal level and use the energy to light up the city! And so, we use the energy stored in a HOLE!

 

Bart and Bert couldn't help applauding.

 

- Potential negative energy! It all depends on the reference. - Completed Bert.

 

- What can't you do with a good knowledge of physics? Simple and obvious principles but used intelligently. We still have a lot to learn.

 

- Yes! - completed Bert. - It is not just knowing the principles but knowing how to interpret and use them. We lost the bet!

 

- But with the satisfaction for learning something new.

 

Even the city mayor, who was watching the broadcast, had an unexpected reaction.

 

- Damn it! This means that I can open holes in the city at will, without having to close them! I can use it to store energy!

 

It was not quite like that, which was explained by an advisor, but it had touched the politician's pride.

 

After all, being congratulated by many for the explanations and clarifications, very consistent, we found Professor Ventura, Bart and Bert at the ice cream parlor, each with a nice popsicle.

 

- You won, but I'm still not entirely convinced. The energy was available there, but no one had realized. - Bert started.

 

- Yes, it's the Columbus' egg (*). The solution was there all the time, but no one had realized. One just needed to know how to explore. - Explained Professor Ventura, who continued.

 

- And like this solution, there must be many others, right under our noses. It's just knowing how to explore.

 

Bart commented:

 

- Yes, but it takes a lot of imagination and a sense of observation. A quality that every maker, scientist, inventor must have.

 

- Certainly! These are the qualities that great creators have. It is not something you learn. - Completed Professor Ventura.

 

- And certainly, you have that quality! You can even see other ways of storing in places that we can't even imagine. It goes without saying.

 

And, looking at his ice cream, Professor Ventura completed it in a way that no one would have imagined, least of all Bart and Bert.

 

- Yes, we can store energy even in this ice cream ...

 

Bart and Bert jumped out of their chairs.

 

- Not this one!

 

- We bet! - completed all three at the same time, sealing the bet shaking hands.

 

And, really, Professor Ventura bet with the two students that he would have an efficient, scientifically consistent, and technologically possible way to store energy in an ice cream.

 

But this is a topic for our next story: “Storing Energy in an Ice Cream”