The primary raw materials for urea production are ammonia (NH3) and carbon dioxide (CO2), both of which are derived from natural gas or other hydrocarbons. Ammonia and carbon dioxide react under high pressure and temperature to form ammonium carbamate, which is then dehydrated to produce urea fertilizer.

Simply air bubbles form when the amount of dissolved air in a solution exceeds the saturated solubility. In other way, water contains dissolved air, molecules of which accumulate around tiny imperfections on the glass. This process of nucleation continues until a bubble forms, breaks free and rises to the surface. 

Hydrogen is lighter than helium but it is combustible and as oxygen is present in the air, there is a risk of explosion and fire anywhere. Helium is lighter than air and it is a non-combustible and inert gas. So, it is used to fill balloons.

Argon gas is used in fluorescent and incandescent light lights to create an inert atmosphere inside the light. Argon is heavy (compared to neon or helium) which allows for more deposition of energy within the gas. This increases the detector's efficiency.

Nitrogen is used in incandescent bulbs to prevent the tungsten filament from oxidizing at high temperatures. It is an inert and cost-effective gas that reduces filament evaporation, prolonging the bulb's life. Sometimes, it is mixed with argon for better performance.

Helium is the hardest gas to liquefy because it has the lowest boiling point of all the elements at about 4.2 Kelvin (-268.9°C) under atmospheric pressure. This is due to its weak intermolecular forces (van der Waals forces), as it is a noble gas with a fully filled electron shell, making it chemically inert and nonpolar.

To liquefy helium, extremely low temperatures and high pressures are required. Even then, helium remains a quantum mechanical substance, and below 2.17 Kelvin, it forms a superfluid state (liquid helium-II) with unique properties like zero viscosity.

The electrical wire and cables shrink in cold weather and become loose in hot weather. If the wires are set tightly between the poles, in winter or cold weather the poles may bend or break due to contraction.

Soft water is free from dissolved salts, calcium, iron, or magnesium. This water can only be found from rain which is also called the highest natural sources of such water. Another way is to make it into lab-Distill water.

A dry cell is a type of electric battery, commonly used for portable electrical devices. A standard dry cell comprises a zinc anode, usually in the form of a cylindrical pot where an oxidation reaction occurs (loss of electrons for the electroactive species), with a carbon cathode in the form of a central rod where a reduction reaction occurs (gain of electrons for the electroactive species).

Lead-acid battery is a type of rechargeable electrochemical battery storage available. In a lead-acid battery, the cathode is made of lead-dioxide, and the anode is made of metallic lead. The two electrodes are separated by an electrolyte of sulfuric acid. As the battery charges, the sulfuric acid reacts with the lead in the anode and cathode to produce electric power.