Results

There are many different processes and phenomena that emit electromagnetic radiation. Humans have taken advantage of many of these processes to develop technologies that use electromagnetic radiation.

The beauty of a coral reef, the warm radiance of sunshine, the sting of sunburn, the X-ray revealing a broken bone, even microwave popcorn—all are brought to us by electromagnetic waves. The list of the various types of electromagnetic waves, ranging from radio transmission waves to nuclear gamma-ray (γ-ray) emissions, is interesting in itself.

Even more intriguing is that all of these different phenomena are manifestations of the same thing—electromagnetic waves (see Figure 15.1). What are electromagnetic waves? How are they created, and how do they travel? How can we understand their widely varying properties? What is the relationship between electric and magnetic effects? These and other questions will be explored.

Photoelectric materials emit electrons when they absorb light of a high-enough frequency.

This video explains the theorem of Pythagoras.

By the end of this unit you will be able to:

• Identify different types of triangles.
• Investigate the relationship between the sides of a right-angled triangle to develop the Theorem of Pythagoras.
• Use the Theorem of Pythagoras to find missing lengths in right angled triangles.

This short online resource elaborates on the difference between climate and weather and why understanding the climate is important.

This short online tutorial highlights the difference between weather and climate.