# Oscillations and Waves

## What are oscillations?

Oscillations are variations of a medium or system over a period of time, a repeated movement around an equilibrium position. A system is said to oscillate when some of its parameters (such as voltage, intensity, or speed) achieve values that are repeated with recurrence.

## What are waves?

On the other hand, waves are disturbances of a medium in space, such as density, pressure, or magnetic field. These may be elastic or deformable, and they involve the transportation of energy without the need for there to be movement of matter.

## What is the relationship between oscillations and waves?

Understanding the operation of oscillations thus allows us to describe wave movements, since the latter are generated by the former.

The phenomenon of oscillations and waves can be explained in as everyday a situation as throwing a stone into a body of water: if the latter is in a state of rest, by causing the stone to act on it, it creates a disturbance that is transferred and transmitted to the elements around it. Over time, this disturbance reaches more points.

In this process there is no movement of mass in the medium; instead, what is transmitted is energy, which passes from one element to another through the medium propagating the disturbance.

## What are the basic concepts associated with oscillations?

• Period (T): the time taken by the body to perform an oscillation.
• Frequency (f): the number of oscillations that a body performs in a unit of time.
• Elongation (x): the distance between an equilibrium position and the body in any period of time.
• Amplitude (A): the distance that exists between an equilibrium position and any of the extreme positions.

## What are the basic concepts associated with waves?

• Cycle or phase: the movement ordered by a wave that is between two consecutive points and in a similar position.
• Period (T): time for a cycle to be completed.
• Frequency (f): the number of cycles performed in a unit of time.
• Wavelength: the distance measured in the direction in which a wave propagates, between two consecutive points of a similar position.
• Speed (v): the speed with which a wave propagates in a medium. Normally, it propagates in a straight line and at a constant speed.
• Crests: highest points of the waves.
• Valleys: the lowest points of the waves.
• Amplitude (A): the height of a ridge or the depth of a valley.

## What types of oscillations are there?

1. Simple oscillations: movements that a body undergoes when going from one extreme to another.
2. Double or full oscillations: movements that a body undergoes in moving from one extreme position to another and then back to the first.
3. Free oscillations: these occur when a mechanical system is stretched or compressed and released, thus being able to stay that way indefinitely if there were no dissipative force. One example of this type of oscillation is the movement of a swing.
4. Damped oscillations: these occur when the energy of a system is gradually dissipated by friction or another type of resistance. Its elongation is gradually reduced at a rate slower than free oscillation, until it reaches an equilibrium position. One example of this type of oscillation is the movement of a measuring needle on a scale that reaches its equilibrium point after weighing an object.
5. Forced oscillations: these occur when a periodic force is applied from the outside and feeds the system’s own oscillations. Returning to the swing example, a forced swing is when a person pushes the swing periodically to maintain the swing.

## What types of waves are there?

1. Longitudinal waves: in these, the parts of the medium vibrate parallel to the direction of the waves; for example, sound waves.
2. Transverse waves: in these, the particles of the medium vibrate perpendicularly to the direction of the waves; for example, the waves of a string.

## Why are oscillations and waves important?

Both oscillations and waves are important because they explain the behavior of periodic phenomena, as well as the transmission of energy without the need for the presence of a mass or body.

These movements are therefore the basis for understanding the characteristics of variations supported by fields, such as sound when speaking. Speaking involves a mechanical release of air, a medium that allows the propagation of sound; when speaking, they generate sound waves that are transmitted through a material medium and which changes the density of the air inside the medium.