## Available courses

### Fractions

In mathematics, a fraction is a number that represents a part of a whole. It consists of a numerator and a denominator. The numerator represents the number of equal parts of a whole, while the denominator is the total number of parts that make up said whole.

### Sound Effect

Sound is a pressure wave which is created by a vibrating object.

This vibrations set particles in the surrounding medium (typical air) in vibrational motion, thus transporting energy through the medium. Since the particles are moving in parallel direction to the wave movement, the sound wave is referred to as a longitudinal wave. The result of longitudinal waves is the creation of compressions and rarefactions within the air. The alternating configuration of C and R of particles is described by the graph of a sine wave (C~crests, R~troughs)

The speed of a sound pressure wave in air is 331.5+0.6Tc m/s , Tc temperature in Celsius The particles do not move down the way with the wave but osciallate back and forth about their individual equilibrium position.