- - empty 2L plastic bottle - 1 pc .;
- - an empty plastic bottle 0.5 l - 1 pc .;
- - scissors;
- - dry ice;
- - isopropyl alcohol;
- - needle
When creating liquid nitrogen is important to observe the necessary precautions.Wear tight jeans, a T-shirt with long sleeves and gloves.Also, use safety glasses for eyes and avoid the likelihood of getting your hair in the range of the experiment.This can prevent possible injuries.
Use the 2-liter plastic bottle.It should be empty, clean and dry.You can remove the label to monitor the experiment.Take sharp scissors and cut about 7.5 - 8 cm top of the bottle.The excess part of the emissions.
about half fill the prepared 2l bottle with dry ice.Always wea
r gloves when handling dry ice, because touching it can lead to serious injury.
For liquid nitrogen, dry ice, you need to add isopropyl alcohol (in other words, rubbing alcohol).To safely add alcohol, using a large needle make several holes in the bottom and sides of a 500 ml plastic bottle.Then put it into a 2-liter bottle and gently place between pieces of dry ice.Thus most of the smaller bottles should be covered with dry ice.As necessary, you can add dry ice.Make sure the holes a little bottle open and dense particles do not block access.
Carefully pour a small amount of alcohol in a large plastic bottle on top of dry ice.The result of combining the two compounds will be the formation of liquid nitrogen, which will flow into the bottle through the smaller holes created previously and condense.
Once inside the bottle is at a sufficient amount of liquid nitrogen, quickly remove it from the 2-liter bottle.Place the liquid nitrogen into a reliable container and label it accordingly.For future use, it can be stored at room temperature for 30 days.
Tip 2: How to make liquid nitrogen
liquid nitrogen (N2) represents a clear liquid with a little less than water density.In this state nitrogen has an extremely low temperature (about - 196 degrees).How can I obtain a liquid nitrogen ?
Since liquid nitrogen when exposed to air and heat quickly evaporates rapidly increasing in volume, it is stored in special conditions, either in special low-temperature containersat elevated pressure, or "Dewar vessels."
currently used cryogenic method, ie a method of deep cooling.It is used in industrial scale and in the laboratory.
key point - getting very low temperatures required for liquefaction of air.There are three methods you can use: - Using low-boiling liquid, evaporation, they absorb large amounts of heat, thereby cools vozduh.-by throttling (Joule-Thompson).-By
adiabatic expansion of the gas.
adiabatic expansion of the gas.
most common first two methods.When using low-boiling liquids are applied consistently more refrigerants selected in such a way that one liquefaction occurred due to the evaporation of the other.The method is very effective, but structurally complex.
The second method requires the prior strong compression of air (200 - 250 bar).It is widely used, despite the low effectiveness of such systems.
widely used in various fields of industry and science.For example, as the cutting element (cutting, cryogenic), molecular biology, genetic engineering, breeding case (as a cooling element during storage cell cultures and DNA fragments), as extinguishing agents where necessary rapid cooling equipment, sensors, etc.It is also used in medicine for the treatment of scars, warts, warts, acne.Essential for all sorts of emergency situations where there is a need to deliver a large amount of blood.