10.2 study slide

What is energy?

Energy is ‘the ability to do work’. That is, it is the ability to make something observable happen.  We know that: –all things have energy even if they are not moving –energy cannot be created or destroyed. This statement is known as the Law of Conservation of Energy. It means that the amount of energy in the universe is always the same. –energy can be transferred to another object (for example, from a cricket bat to a ball) or transformed into a different form (for example, from electrical into sound) –energy can be stored.

Types of energy

• Ch. 10.2 flashcards

Inefficient use of energy

Every electrical appliance you use, whether powered by batteries or plugged into a power point, converts electrical energy into other forms of energy. Most of that energy is usually converted into useful energy — but some is converted into forms of energy that are wasted or not so useful. But all of the electrical energy is converted — that’s the Law of Conservation of Energy in action. Not of the wasted energy is actually lost. Here are some examples: Microwave - used to create thermal energy for food but can be wasted by heating air in the oven. Television - used to create light and sound but wastes some of its energy heating the air surrounding it. Hair dryer - this is used to create thermal and kinetic energy but also produces sound energy Electric cooktop - used to create thermal energy for food but also produces light and heat energy.

Light Bulbs and their efficiency

Light+Bulbs (binary/octet-stream)

Caption: : LED's are the most efficient light bulbs