Search Resources

Speed necessary for the space station to stay in orbit.

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.

In this lesson you will learn that:

• Static electricity is a build-up of charge in an object.
• The build-up pf charge is caused by insulating materials rub against each other.
• The motion of these charges causes small shocks, lightening and sparks.
• These charges can be detected. 
• Certain materials can be classified as insulators, and others as conductors.
• Capacitors are small devices in circuits which can store charge.
• Lightning rods are used to allow charges from strikes to travel safely and dissipate in the Earth

The phases of Meiosis.

Explanation of the phases of mitosis

In this lesson you will learn about the following forms of renewable energy sources:

• Solar energy
• Water energy
• Wind energy
• Sea wave energy
• Geothermal energy

In this unit you will: 

• Understand that temperature is a measure of average kinetic energy.
• Learn about the various temperature scales that are commonly used in science.
• Learn to read temperature scales.
• Differentiate between various thermometers (alcohol or mercury-based).
• Understand that physical properties change when there is a change of temperature.

Short tutorial on trigonometry

Details on the light-dependent reactions of photosynthesis

C-4 Photosynthesis: How some plants avoid photorespiration