Results

Patterns and processes of evolution. How evolution and natural selection are reflected in the similarities and differences of organisms. 

The idea of the electric field, how it's useful, and explains how the electric field is defined.

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.

Forces at a distance are explained by fields (gravitational, electric, and magnetic) permeating space that can transfer energy through space. Magnets or electric currents cause magnetic fields; electric charges or changing magnetic fields cause electric fields.

Magnetism is an interaction that allows certain kinds of objects, which are called ‘magnetic’ objects, to exert forces on each other without physically touching. A magnetic object is surrounded by a magnetic ‘field’ that gets weaker as one moves further away from the object. A second object can feel a magnetic force from the first object because it feels the magnetic field of the first object. The further away the objects are the weaker the magnetic force will be.

Food webs are models that demonstrate how matter and energy is transferred between producers, consumers, and decomposers as the three groups interact within an ecosystem. Transfers of matter into and out of the physical environment occur at every level. Decomposers recycle nutrients from dead plant or animal matter back to the soil in terrestrial environments or to the water in aquatic environments. The atoms that make up the organisms in an ecosystem are cycled repeatedly between the living and nonliving parts of the ecosystem.

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

We can analyse the arrows in a food web to identify producers, primary consumers, secondary consumers, and decomposers.

We can analyse the arrows in a food web to identify producers, primary consumers, secondary consumers, and decomposers.