8th Physics

Waves, which exist in mechanical and electromagnetic forms, have various properties.

1. Something can be "seen" when light waves emitted or reflected by it enter the eye--just as something can be "heard" when sound waves from it enter the ear. (AKSci - A.6)

o Demonstrate longitudinal and transverse waves with slinky.

2. Waves move at different speeds in different materials. (AKSci - A.6)

o Conduct a lab investigation illustrating waves, for example water diffraction, sound waves; bone conduction and air.

Forces affect motion in a variety of ways.

A. Newton's Laws not addressed at this grade level.

B. Gravitational Force and Motion

1. The sun's gravitational pull holds the earth and other planets in their orbits, just as the planets' gravitational pull keeps their moons in orbit around them. (AKSci - A.5)

o Demonstrate with a string and a weighted object.

2. The gravitational pull on an object is the object's weight. (AKSci - A.5)

o Mass several objects with a triple beam balance, calculate the weight, and check the weight with a spring scale.

C. Magnetic and Electric Forces

1. There are two kinds of charges - positive and negative. Like charges repel one another, opposite charges attract. In materials, there are almost exactly equal proportions of positive and negative charges, making the materials as a whole electrically neutral. (AKSci - A.5)

o Demonstrate electrostatic charges and electric neutrality with a balloon and tissue paper.

D. Pressure

1. Pressure is dependent on the weight of fluid on an object. (AKSci - A.5)

o Demonstrate water pressure with a paper cup and pencil.

The use of energy and its products affect the lives of all peoples of the world.

1. Different ways of obtaining, transforming, and distributing energy have different environmental consequences. (AKSci - A.8c)

o Select a location on a globe or map, determine its population, identify the natural resources available and the demand for them, and make predictions as to the future resource depletion. Identify stockholders; prepare a position statement; and develop an action plan to solve the problem.

Energy transformations occur at both micro and macro levels.

1. Most of what goes on in the universe-from exploding stars and biological growth to the operation of machines and the motion of people--involves some form of energy being transformed into another. Energy in the form of heat is almost always one of the products of an energy transformation. (AKSci - A.8c)

o Use an existing example or design a system or device that involves several energy transformation, labeling each form of energy represented.

2. Energy sources can be classified as renewable or nonrenewable. (AKSci - A.8b)

o Classify 10 energy sources as renewable or nonrenewable.

3. Electrical energy can be produced from a variety of energy sources and can be transformed into almost any other form of energy. (AKSci - A.4, A.8c)

o Use an existing example or design a system or device that involves at least one electrical energy transfer.