There are no ‘collections’ in this Microcosmo, but real working instruments, showing events in real time as if they were real experiments. Tools that for the visitor are a guide and companion on this particular ‘journey’ into a world where the rules are not always those of common sense.
SEE OUR CATALOGUE.
AEROGEL
Aerogel material is essentially composed of silicon like glass, but with a sponge-like structure whose hollow spaces make up 99.9 per cent of the volume. However, compared to glass, Aerogel is up to seven hundred times less dense. Discovered in the late 1960s, the material Aerogel has several applications. It is used as a thermal insulator especially in aeronautics (due to its very light weight) and for absorbing sound.Aerogel is used in particle detectors called RICH (acronym for Ring Imaging Cherenkov), which can identify the mass of particles based on the Cherenkov radiation that a charged particle produces precisely when passing through matter. Cherenkov light is emitted when the velocity of the charged particle is greater than the speed of light in that material. The ratio of the two velocities determines the angle of emission of this light with respect to the direction of the particle. If the material is highly transparent, and Aerogel is, the emitted light can be collected on a plane. The angle at which light is emitted depends on the mass and velocity of the particle in question. It is therefore the physical observable that allows the mass of the particle to be traced.
FOG DIFFUSION CHAMBER
It allows continuous detection of particles passing through its sensitive volume.
The chamber visualises the tracks of the particles by forming alcohol droplets on the electrical charges (ions) that each ionising particle leaves along its track. For this to happen, the vapour must be supersaturated, i.e. ready to form mist. This condition occurs near the cold bottom of the chamber (around -30°C) where the vapour diffusing from above is oversaturated, thus forming a visible droplet trail.
One can thus see various types of particles such as alpha particles (they ionise a lot, creating dense and relatively short tracks), electrons (thin and tortuous tracks that sometimes cross the entire chamber) and cosmic radiation particles. Alpha particles (helium nuclei, i.e. two protons and two neutrons bound together) are almost always due to decays of radon, which is always present in very small quantities in the air, while electrons have various origins: beta decays (electron coming out of the nucleus), photoelectrons and Compton electrons produced by diffuse gamma radioactivity. Although not frequently, cosmic ray events characterised by longer tracks can sometimes be seen.
SPARK CHAMBER
The Spark Chamber is an instrument for the detection of charged elementary particles.
This chamber made it possible to observe cosmic rays and achieve a greater knowledge of the subatomic particles that make up our universe. These are generally electrons, muons protons and other particles produced in the upper layers of the earth’s atmosphere by collisions with high-energy particles from all directions from all directions in our galaxy and from various points in extragalactic space.
Collisions with atoms in our atmosphere produce swarms of particles that reach the ground.
The spark chamber was invented by two Japanese physicists Shoji Fukui and Shigenori Miyamoto nel 1958. It has been widely used in various experiments with accelerators or in cosmic ray observations.
As the charged particles pass through the chamber, they ionise the gas molecules (mixture of Helium and Neon) which, accelerated by the electric field between the plates, generate electrical discharges that allow their trajectories to be observed.
PLASMA SPHERE
The light streaks inside the sphere are generated by electrons accelerated from the centre outwards.
As the electrons collide with the gas atoms inside the sphere, they cause light to be emitted as a result of the electrons falling back into the atomic orbits allowed to them.
Touching the outside of the sphere with the hand has the effect of increasing the potential difference resulting in a higher concentration of the light strips.
RADIOMETER
The operating principle of this device is based on the different absorption behaviour of white surfaces compared to black ones.
In fact, the molecules of the gas are hit by photons of electromagnetic radiation and move with speeds proportional to the energy of the photons of the incident radiation.
The black faces of the radiometer absorb the molecules’ shocks while the white faces repel them.
The energy imbalance between the two surfaces causes the faces to rotate.
CROOKES TUBE
The Crookes cathode ray tube is a glass tube containing rarefied gas at a pressure of about one hundred thousandth of atmospheric pressure. Inside are two metal electrodes with a high voltage difference (a few thousand volts).
Electrons are emitted from the cathode by the bombardment of gas ions accelerated by the applied voltage.
Along the electron beam is an obstacle in the shape of a Maltese cross, the shadow of which can be seen on the screen as a greenish light.
This light (fluorescence) is produced when electrons bombard this type of glass.
The electrons behave in this way like a beam of light even though other experiments have shown that they are particles with mass and an electrical charge.
Like all electric charges in motion, electrons are deflected by a magnetic field, as can easily be observed by bringing the magnet closer to the tube.
