Telescope : A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation (such as visible light). When invented and by who – The earliest recorded working telescopes were the refracting telescopes that appeared in the Netherlands in 1608. Their development is credited to three individuals: Hans Lippershey and Zacharias Janssen, who were spectacle makers in Middelburg, and Function : * to gather as much light from an object as possible, to focus the light into a sharp image, and * to magnify the image. Microscope : A microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy. When invented and by who – An early microscope was made in 1590 in Middelburg, Netherlands. Function – Microscopes are instruments that uses lens to produce magnified images of objects too small to be seen by the eye. Megaphone :
Megaphone is a portable, usually hand-held, cone-shaped acoustic horn used to amplify a person’s voice or other sounds and direct it in a given direction. The sound is introduced into the narrow end of the megaphone, by holding it up to the face and speaking into it, and the sound waves radiate out the wide end. The megaphone increases the volume of sound by increasing the acoustic impedance seen by the vocal cords, matching the impedance of the vocal cords to the air, so that more sound power is radiated.
It also serves to direct the sound waves in the direction the horn is pointing. It somewhat distorts the sound of the voice because the frequency response of the megaphone is greater at higher sound frequencies. Since the 1970s the voice-powered acoustic megaphone described above has been replaced by the electric megaphone, which uses electric power to amplify the voice. (Function in here) When invented and by who – The initial inventor of the speaking trumpet is a subject of historical controversy, as both Samuel Morland and Athanasius Kircher lay claim to the device
Headphone / Earphone : Headphones are a pair of small loudspeakers that are designed to be held in place close to a user’s ears. Headphones either have wires for connection to a signal. When invented and by who – The first truly successful set was developed by Nathaniel Baldwin. “ Function * you can get high and clear quality sound when you listen to music and/or watch movie and minimize strength sounds that you don’t want. * you can manage air circulation to your ears smoothly because there is gap between headphone and ear.