New Unit: ENERGY

Class Starter Is energy a form of matter? Explain. Give some examples of different forms of energy Give a definition of energy. What units are energy expressed in?

Class Starter 1) Is energy a form of matter? Explain. No, energy is not matter. It does not have mass and take up space

2) Give some examples of different forms of energy. Energy Form Energy Source Solar energy Sun Elastic energy Wire spring Electrical energy Power station Thermal energy Fire Radiant energy Electric light bulb Chemical energy Living cell Mechanical energy Moving Vehicle Wind energy Wind Sound Energy Sound Hydraulic energy Waterfall Nuclear energy Nucleus of an atom

Class Starter 3) Give a definition of energy. Energy is the ability to do work or produce change. Ex: Jogging is work that demands energy Melting an ice cube is change that requires energy

4) What units are energy expressed in? Energy is expressed in joules. One joule (J) represents the energy needed to lift an object weighing 1 newton (N) (aprox 100g on Earth) to a height of one meter. If we increase the mass of an object, it will require more energy to lift it. It requires more energy to lift an object to a higher height.

James Prescott Joule The English physicist that studies all different aspects of energy

Different Forms of Energy

Thermal Energy Question: What exactly are we measuring when we take the temperature of a substance? We are measuring the degree of agitation of the substance’s atoms and molecules. The warmer the substance, the more the particles that compose it move!

Thermal Energy Thermal energy is the energy that comes from the random movement of the particles that make up a substance Examples of work or change that can be accomplished by thermal energy: Melting of snow by the heat of sun in the spring The production of water vapour in order to advance the train by the boiler of a steam engine The lifting of a hot-air balloon into the sky by the burner’s heating of air inside the balloon

Radiant Energy Radiant energy is the kind of energy that is contained in and transported by electromagnetic waves. Visible light is just one wave type belonging to a group called the electromagnetic spectrum Different types of waves are determined by their wavelength  the distance between two consecutive peaks or valleys.

The Electromagnetic Spectrum

Radiant Energy Electromagnetic waves transport energy from one place to another The quantity of the transported energy depends on the wavelength The shorter the wavelength the more energy the wave can transport Ex: X-rays have a shorter wavelength than microwaves and therefore have more energy.

Radiant Energy Examples of work or changes that can be accomplished by radiant energy: Producing images inside the body using X-rays Getting suntanned and sunburned from ultraviolet rays Treating certain types of cancer with gamma rays

Chemical Energy Chemical energy is the energy stored in the bonds between atoms of a molecule Chemical energy is only released when the chemical bonds in a molecule are broken apart and rearranged in a different matter. Ex: When a candle is lit, a chemical change occurs in the candle’s molecules, releasing chemical energy (in the form of light).

Chemical Energy The amount of energy in a chemical bond depends on the strength of that bond. The stronger the bond, the more energy it contains. Examples of the work or changes that can be accomplished when chemical energy is released. The operation of a car motor by the combustion of gasoline Cellular respiration: living organisms use the chemical energy stored in a glucose molecule to live.

Mechanical Energy Mechanical energy is the energy that results from the speed of an object, its mass, and its relationship to its surroundings. The faster a moving object, the more mechanical energy it has The damage caused by a car moving at 100 km/h will cause more damage than a car moving at 30 km/h. The higher an object is positioned in relation to its surroundings, the more mechanical energy it has A baseball falling from the 10th floor of a building onto your head will hurt a lot more than from the 1st floor.

Mechanical Energy The greater the mass, the greater the mechanical energy Falling from the same height, a will cause more damage if it hits a car than a stone. Examples of the work or changes that can be accomplished by mechanical energy The creation of a crater by an asteroid The powering of a hydroelectric power station by a waterfall (hydraulic energy)