Resultaten

These three short online lessons discuss asteroids, comets and meteors.

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.

Introduction to passive and active transport

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.

Osmosis is the movement of water across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration. Osmosis helps regulate the flow of water in and out of cells, which is crucial to their function.

Other objects in the solar system are discussed in this online textbook viz. asteroids, meteorites, comets and dwarf planets.

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