Permafrost

The permafrost is the permanently frozen soil in very cold areas of the planet. It is really hard to dig and a jack hammer is needed.

Study of soil in Alaska (CC Attribution-Share Alike 2.0 Generic)

In this video we can see burning wood in a trench so the permafrost melts and ease the digging works.The video belongs to my short documentary film "Yakutos".

Solar furnace made with crisps bags

With bags of crisps, well in this case they were nachos and a parabolic dish. It is possible to burn a piece of wood or to boil water.

Air density and temperature. Helium balloon.

The buoyancy of an helium balloon depends on the temperature of the air where it is floating or sinking. In this experiment, the balloon is ballasted to  desdend slowly. If we put the balloon at a colder place, the surrounding air is less dense, so the balloon goes up. It happens the same way with hot air. Hot air ascends, well not that hot air ascends but really colder air (denser) goes down attracted by gravity force and then the hot air (or helium, hydrogen, etc.) is displaced upwards.

Calcium carbide synthesis.

Calcium carbide was synthetized for the first time by Friedrich Wöhler in 1836 mixing lime (CaO) and coke (C) in an electric arc furnace. Today the synthesis process is the same. CaO + 3 C → CaC₂ + CO . The main uses of calcium carbide are: production of acetylene when reacts with water; production of calcium cyanamide (fertilizer) and steelmaking (desulfurisation: to clean the sulphur from cast iron or pig iron). The industrial production began in 1895 and peaked in the 1960's. From then, the production of calcium carbide is declining, mainly because acetylene is produced from petrochemical sources, the use of other than oxi-acetylene welding techniques and the less use of calcium cyanamide.

Bernoulli principle.

Since fast moving air is at lower pressure than slow air the balloon is stabilized without getting out of the stream.

The Joule effect

When the electricity flows through a conductor, since it has a finite resistance, electric energy is converted to heat. The heat is generated when the conduction electrons transfer energy to the conductors atoms through collisions.

Joule heating is in some cases unwanted, and efforts are made to reduce it. However, many applications rely on Joule heating: cooking plates, electric heaters or irons. The National Electrical Code (regionally adoptable standard for the safe installation of electrical wiring and equipment in the United States) defines de section (thickness) of the wires depending on the current (amperes) and other factor like isolation, or number of wires packed in the cable. If the wire is too thin, the resistance is bigger and the more heat is generated. In this video the current is flowing through a single thin copper wire ....

Hello world!

Hello world!. This is Mopatin´s first entry. We will show you curiosities, explanations, demonstrations, magic, ... all about and related to science and thechnology.