Energy transfer by design

-Lots of things can go wrong if we don't control energy transfer. For example, a car engine that overheats can go up in flames

-The cooling system of a car engine transfers energy from the engine to a radiator. The radiator is shaped so it has a large surface area. This increases the rate of energy transfer through convection in the air and through radiation 

-A motorcycle engine is shaped with fins on its outside surface. The fins increase the surface area of the engine in contact with air so the engine transfers energy to its surroundings faster than if it has no fins 

-Most cars also have a cooling fan that swithes on when the engine is too hot. This increases the flow of air over the surface of the radiator 

In a vacuum flask there are many features to keep your drink either hot or cold. These features are things such as;

• Vacuum between the two walls of the container- cuts out energy transfer by conduction and convection between walls 
• Glass is a poor conductor so there is little energy transfer by conduction through glass 
• The glass surfaces are silvery to reduce radiation from the outer wall 
• The spring supporting the double-walled container is made up of plastic which is a good insulator 
• The plastic cap stops cooling by evaporation as it stops vapour loss from the flask. Energy transfer by conduction because the cap is made from plastic 

-The bigger the tempertaure difference between an object and its surroundings, the faster the rate at which energy is transferred

-The rate at which an object transfers energy depends on its design. The design factors are;

• The materials the object is in contact with 
• The object's shape 
• The object's surface area 

-Also, the material it's made from becuase they affect how quickly its temperature changes when it loses and gains energy