In 1906, Reginald Fessenden achieved the first analog transmission of sound over radio waves on Christmas Eve. An analog transmission is like a flowing river that continuously changes its speed and depth to carry things along its path. In analog communication, sounds or images are directly transformed into continuous signals that mimic the original. For example, if you shout into a microphone, the resulting signal fluctuates exactly like your voice waves, getting higher and lower with the pitch and volume of your shout.

Before that, Guglielmo Marconi, an Italian inventor, transmitted the first analog radio signals in 1895, using a process where a continuous signal, like a wave, is modified to represent information. 

In the 1940s, the first digital transmission occurred. A digital transmission is like sending a message using Morse code, where everything is broken down into a series of beeps (dots and dashes). In digital communication, sounds or images are converted into a series of numbers (0s and 1s). This digital code represents the sound or image but in a format that’s either on or off, much like flipping a switch. This makes digital signals easier to send without loss of quality, even over long distances.