What is the importance of ...

refrigeration cycle in the refrigerator

cooling the food inside the refrigerator by continuously transferring heat from inside the refrigerator to its outside

polystyrene cups

they are used in thermal insulation

Instant cold compresses

compresses are used only once to reduce the severity of swelling 

instant hot compresses

compresses are used only once to relieve pain associated with muscles fatigue

Exothermic reactions for some types of insects

Luminous insects use light as a result of exothermic reactions inside their bodies in various purposes such as mating and self-defense

self-heating cans

Warming coffee or heating the food inside it without the need for an external heat source

The thermite reaction

This reaction is used in welding the railway tracks

Ethyl alcohol (ethanol)

It is used as fuel for cars in some countries after mixing it with gasoline

Fuel of the future

It is used as fuel for cars and trucks powered by fuel cells (hydrogen fuel cells)

Natural gas and butagas

They are the main fuels used in households

Ethanethiol gas

It is added with very small amount to natural gas and butagas to take the appropriate safety measures in case of gas leaks

The flame of bunsen burner

It is used as a source of heat in lab

Sparks plugs (Boungies)

They produce a spark used to ignite the mixture of gasoline and air in the combustion chamber of the car engine during starting.

Oxyacetylene flame

It is used for cutting and welding metals, such as steel (iron) and copper

Fire extinguishers

they are used to isolate fires from air (oxygen)

Sand in laboratories

It is used in extinguishing fires of some metals, such as sodium and magnesium fires

Closing gas valves during fires

Fuel removal

Newton meter (Spring balance)

It is used to measure the force

Cruise control

Keeps the velocity of the cars constant on highways without any direct driver intervention, through using sensors

The seat belt

Reduces the rushing forward of the driver towards the steering wheel or the windshield during sudden stopping

The airbag

Works with the seat belt to reduce collision impact by increasing the time of impact.

The tower crane (Winch)

It is used to lift concrete blocks which are used in constructing large buildings.

Pulley

It is used in changing the direction of the force during lifting or lowering weights

The inclined plane (Ramp)

It is used to save effort

The wheel and the axle

They are used together in multiplying the exerted force or increasing the speed

Wedge

It is used in changing the direction of the applied force

Gears and belts

They are used in transferring the motion and changing the speed as in bicycles.