An experiment carried out in orbit shed light on the rather complex processes that now and then occur in our everyday life on earththe flow of blood, ketchup, motor oil and whipped cream. To do this, scientists had to recover data from computers of the crashed shuttle Columbia.
- The mesh fixed between the electrodes is the same paddle with which the sample was stirred.
- The xenon phase diagram illustrates the concept of a critical point the maximum temperature and pressure at which xenon can exist simultaneously in the form of a liquid and a gas
2003-th year: the Columbia shuttle at the start
Let’s start with a little experiment. To do this, you will need a can of whipped cream, squeeze more onto a spoon and observe carefully. If you were careful enough, you noticed that the cream flows out of the container like a liquid, and after a while, after falling on a spoon, it looks almost solid. What happened to them? Let’s think about it, putting cream in our mouthin the name of science.
This is due to a change in the viscosity of the creamy foam. When a part of a substance (in this case, foam) shifts relative to the rest of its mass, its viscosity decreases (the foam “becomes thinner”), and it becomes more fluiduntil the movement stops. A similar phenomenonshear thinningis observed in many substances, and in the case of motor oil or blood is much more important than in our everyday experiment. For example, it increases the wear of automobile engines and is undesirable in engine oil. But with ketchup, the opposite is true: it allows your favorite sauce to drain from the bottle, but remain a “slide” on top of the dish. The Nangs are perfect in this case. Services like nangsta.com.au provide fast cream charger delivery to Greater Melbourne and are open at night and on weekends.
The Right Mechanism
Despite all the routine, the internal mechanisms of this process are still not completely clear. Its details are due to intermolecular interactions in a liquid, and these interactions can be very, very complex. And even for the simplest liquids, it was not possible to confirm the existing theories in practice. Until recently: a corresponding experiment was carried out in orbit.
- The project, called Critical Viscosity of Xenon-2 (CVX-2), took place on the Columbia shuttle, which died in 2003 due to the destruction of the thermal insulation layer upon entering the atmosphere. Fortunately, the hard drives of the on-board computers were found among its wreckageand they turned out to be intact enough for scientists, with difficulty, to recover the information stored on them.
- The essence of the CVX-2 experiment was to study the change in the viscosity of xenon, an inert gas that is widely used in industry. Unlike most other gases, gaseous xenon consists of monatomic particles, and thus is closer in characteristics to the “ideal gas”, which is considered by classical thermodynamics. So, unlike the same cream, which consists of a complex mixture of large organic molecules, xenon is much easier to study.
True, under normal conditions such “simple” substances do not change the viscosity. But everything changes in the region of the critical point a special combination of temperature and pressure conditions, at which a substance simultaneously exhibits the properties of a liquid and a gas. At this point, xenon resembles dense fog, a mixture of micro-regions with slightly higher or lower density. These regions constantly form and disintegrate like bubbling foam, creating structural conditions in pure and “simple” xenon, similar to complex liquids, such as, say, our blood.