energy-the ability to cause change
transferring energy-everything around you has energy, but you notice it only when a change takes place. When a change takes place energy is transferred from one object to another.
kinetic energy-energy an object has due to its motion
If the speed of an object is faster it has more kinetic energy.
If the mass of an object is larger it has more kinetic energy.
potential energy-energy of position
An object that is higher off of the ground has more potential energy. The more mass an object has the more potential energy the object has.
Chapter 5 Section 2 Notes:
Energy is continually transforming between one form and another.
When you eat, the food is transformed into chemical energy, which is transformed into kinetic energy. Some of the food is changed to thermal energy.
Law of conservation of energy: says that energy is never created or destroyed, just changed. pg. 138 fig. 9 Many machines are devices that transform energy from one form to another.ex. car transforms chemical energy in the gasoline into energy of motion which is kinetic and some into thermal.
pg. 140 and 141-fig. 12
Thermal energy only moves from something at a higher temperature to something at a lower temperature.
ex. pg. 142 fig. 13
Generating electrical energy:
fig. 14 pg. 142
Ways electrical energy is generated:generatornuclear energydam
windmill
solar panels
Chapter 5 section 3
Energy Resources:
Energy cannot be made, but must come from the natural world.
Two sources of energy the Earth receives is from the sun and radioactive atoms in the Earth’s interior.
Energy from the Sun has a bigger impact on our life.1. Fossil Fuels: coal, oil, and natural gas
made from the remains of microscopic organisms that lived in Earth’s oceans millions of years ago.
Made from heat and pressure
Fossil fuels are a nonrenewable resource. Which means that we are using them up faster than they can be replaced.
Advantages: inexpensive
Disadvantage: pollution2. Nuclear Energy: Advantage: no air pollution Supplies lots of energy
Disadvantage: amount of nonrenewable uranium
Waste product is radioactive3. Hydroelectricity: largest renewable source of energy, which means this energy source is replenished continually.
Advantage: pollution free
Disadvantage: disrupts life cycle of many animals
Alternative Sources of Energy: safer and cause less harm to the environment1. Solar Energy: origin of almost all energy that is used on Earth.
Advantage: inexhaustible resource-source that can’t be used up by humans
Disadvantage: expensive
Photovoltaic-a device that transforms radiant energy directly into electrical energy
2. Geothermal Energy: using center of the Earth for heating and cooling.
Advantage: inexhaustible resource
Disadvantage: expensive3. Wind: windmills convert the kinetic energy of the wind to electrical energy.
Advantage: inexhaustible resource
Disadvantage: expensiveConserving Energy: reducing the use of energy1.Turning off lights and appliances when not using them2. Keep doors and windows closed tightly when cold or hot.3. Proper insulation.4. Make cars more efficient.
5. Recycling materials such as aluminum cans and glass.