Results

These two short online tutorials discuss how the earth rotates and then the earth's revolutions.

In the first URL, the YouTube video explains why earth has spring, summer, autumn and winter seasons. The second URL summarizes the key takeaway points.

• Determine the variables that affect how charged bodies interact.
• Predict how charged bodies will interact.
• Describe the strength and direction of the electric field around a charged body.
• Use free-body diagrams and vector addition to help explain the interactions.

This video will look at rotation. Rotation involves turning a shape around a set point.

This online lesson explains what rotations are.

Electric charge comes in two varieties, which we call positive and negative. Like charges repel each other, and unlike charges attract each other. Thus, two positive charges repel each other, as do two negative charges. A positive charge and a negative charge attract each other.

How do we know there are two types of electric charge? When various materials are rubbed together in controlled ways, certain combinations of materials always result in a net charge of one type on one material and a net charge of the opposite type on the other material. By convention, we call one type of charge positive and the other type negative.

Students learn about two-axis rotations, and specifically how to rotate objects both physically and mentally about two axes. A two-axis rotation is a rotation of an object about a combination of x, y or z-axes, as opposed to a single-axis rotation, which is about a single x, y or z-axis. Students practice drawing two-axis rotations through an exercise using simple cube blocks to create shapes, and then drawing on triangle-dot paper the shapes from various x-, y- and z-axis rotation perspectives.