Gutting a llama! Marron manages to dominate the fire in ‘El Hormiguero’

Marron returns one more day to ‘The Anthill’. In this experiment we are going to play with fire. To do this, we will produce a combustion reaction with the help of a blowtorch and we will use metal mesh strainers and sieves, taking advantage of their high thermal conduction.

The fire triangle or combustion triangle is a model that describes the three elements necessary to generate most fires: a fuel (in our case, the mixture of gases in the torch), an oxidizer (the oxygen present in the air) and activation energy that generates a high temperature (heat). When these factors are combined in the right proportion, the fire is triggered. However, in the absence of any of the three, fire does not occur.

The metal from which the meshes of the strainers and sieves are made is a great conductor of heat, in such a way that it allows us to divide the flame in two or prevent its propagation in any direction, thanks to the fact that the mixture of gases from the torch (fuel) it can pass through the mesh and mix with oxygen in the air, but the heat (heat energy) needed to start the reaction is quickly dispersed along the mesh.

Also, if we place the mesh interrupting the flame from the top we can see how the flame is hollow. This is a consequence of what was explained above. When the torch valve is opened, the mixture of high-pressure fuel gases in the bottle is released, but since the oxygen present in the air is required for combustion to occur, the flame is only produced when the mixture is achieved.

But it has not been the only experiment! On the other hand we have cooled a liquid (helium) so much that there is practically nothing colder in the universe than what we have here in front of us. In addition, we are going to get that liquid to go through the bottom of a glass and spill on its own.

To give you a better idea, the temperature on the surface of Pluto, which is more than 5,000,000,000 (five billion) kilometers from the Sun, reaches about -233ºC. Well, the cryostat that we are going to cool will be about 40 degrees colder than the surface of Pluto.

This experiment is a milestone in low-temperature physics. Scientifically it is very difficult to obtain and VERY FEW people have seen it. In fact, there are world experts in low temperature physics with careers of 30 and 40 years who have never seen what you are going to see.

For this we have had the help of the entire department of low temperatures of the Autonomous University of Madrid and especially we have with us Isabel who is a doctor and researcher in the same department.

At the time, it was the experimental discovery of a new state of matter never seen before: the superfluid. He represented the 1978 Nobel Prize in Physics.


How was the experiment?

The first thing has been to make liquid helium superfluid. We will start our experiment by reducing the pressure of the helium inside the cryostat with a vacuum pump in order to lower the temperature of the helium to make it superfluid. At these temperatures all materials in the world are in a solid state, except helium.

This cryostat has to withstand such cold temperatures that there are hardly any materials that allow us to insulate the heat, so we use vacuum layers and even liquid nitrogen layers.

At a certain moment we will pass through a temperature of 2.7 degrees above absolute zero, and at that moment the helium would be colder than the universe. At this temperature, the metals we use every day (aluminum, iron, etc.) become superconductive.

Liquid helium is at a temperature of -269°C. This temperature is so low that it is only 4.2º above the lowest temperature that can exist (absolute zero). To get an idea of ​​how cold it is, liquid nitrogen has a temperature of around -200°C, that is, 69º hotter. For our experiment, we are going to lower these temperatures even further.

While we wait for it to get to superfluid, we have this other transparent cryostat, where we have liquid nitrogen inside. We see that when the glass is immersed in the nitrogen, it, which does have viscosity, behaves like any other liquid, and the liquid stays inside the glass. We can even do the same thing in the cryostat of liquid helium before it becomes superfluid.

Then, we go with the passage of helium to superfluid and check that it has no viscosity

When we get closer to the temperature of 2,172º above 0, we will see that the liquid helium begins to bubble. This is that it is about to change state (like when we are heating water and it starts to boil, but with a new state of matter). When we reach this temperature, the liquid suddenly becomes completely still and calm, and we are in front of a new state of matter, which very very few people have been able to see with their own eyes.

At this moment, we submerge our glass, and when raising it we see that this glass is gradually emptying, and the liquid crosses this layer spilling itself.

We keep cooling the superfluid helium even further, which can reach much lower temperatures. (Depends on the duration of the experiment). The colder the superfluid helium is, the faster the glass inside is going to empty.


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Gutting a llama! Marron manages to dominate the fire in ‘El Hormiguero’