Energy Transfers and Resources Flashcards
Energy cannot be c___ or d___.
Energy cannot be created or destroyed.
In all systems energy is d___, transferred into a less useful form. This energy is described as w___.
In all systems energy is dissipated, transferred into a less useful form. This energy is described as wasted.
How does lubrication reduce unwanted energy transfers?
Lubrication allows surfaces to slide more easily over each other, reducing friction that causes them to heat up.
How does thermal insulation reduce unwanted energy transfers?
Double glazing, carpets, and curtains introduce a layer of low conductivity. Filling wall cavities with insulating material reduces air circulation in the cavity, reducing loss by convection.
The greater the ___ of a material the greater the rate of energy
transfer by c___ across the material.
The greater the thermal conductivity of a material the greater the rate of energy
transfer by conduction across the material.
Describe how two factors affect the rate of cooling of buildings.
Thicker walls decrease rate of cooling, greater thermal conductivity of walls increases rate of cooling.
What is specific heat capacity?
The specific heat capacity of a substance is the amount of energy required to
raise the temperature of one kilogram of the substance by one degree Celsius.
What does it mean to say an energy resource is renewable?
A renewable energy resource is one that is being (or can be) replenished as it is
used.
Give 3 uses of energy resources.
Transport, electricity generation, and heating.
