Because radio waves in the shortwave band can be reflected or refracted from the ionosphere. Therefore, short waves directed at an angle into the sky can be reflected back to Earth at great distances, beyond the horizon.

Due to the refraction of sound, we can hear sounds easily at night than during clear days.

On a clear day, the lower layer of the atmosphere is hotter than the layers above. Since sound travels faster in a hotter medium, its speed is greater near the surface. As a result, the waves are bent away from the surface. Thus, the intensity of the sound waves diminishes and does not seem to travel a long distance. On a clear night, the lower layer of the atmosphere is colder than the air above. Now, the sound waves travel faster at the higher layers than at the lower layers. Thus, the waves are bent towards the earth's surface. The intensity of the sound increases and seems to travel a greater distance.

The differences between transverse and longitudinal waves are as listed below:

The differences between progressive waves and stationary waves are as listed below:

Shortwave radio is used for broadcasting of voice and music, and long-distance communication to ships and aircraft, or to remote areas out of reach of wired communication or other radio services and that’s why it is more energetic than long waves. Shortwave radio is radio communication using the upper MF (medium frequency) and all of the HF (high frequency) portion of the radio spectrum, between 1,800–30,000 kHz. Shortwave radio received its name because the wavelengths in this band are shorter than 200 m (1500 kHz) which marked the original upper limit of the medium frequency band first used for radio communications. The broadcast medium wave band now extends above the 200 m/1500 kHz limit, and the amateur radio 1.8 MHz – 2.0 MHz band (known as the “top band”) is the lowest-frequency band considered to be ‘shortwave’.