Do I need a computer mouse pad?
In the past, a mouse pad was virtually required to use a computer mouse. The early mouse used a small hard rubber ball that would roll as the mouse was moved. This turned small wheels inside the mouse, which sent signals to a computer representing the distance moved. The computer's software would use this data to move the mouse cursor in a corresponding fashion on the computer screen. The mouse pad was needed to provide a surface that the rubber ball could grip enough to move.
Today, the computer optical mouse is designed with an optical sensor, instead of a rubber ball. The optical sensor can "see" the surface it is moving across, sensing the direction the mouse is moving. In many cases, a mouse pad is no longer needed. There's no rubber ball that needs to grip the surface to move.
However, if the mouse is being used on a semi or fully reflective surface, a mouse pad may still be needed. On a reflective surface, the optical sensor would basically only see itself on the surface since the surface would be reflecting an image of the optical sensor. This causes the sensor to not know what direction the mouse is moving. Using a mouse pad would allow the sensor to detect the surface movement and direction.
Some computer mice are a laser instead of an optical sensor. Technically, the laser mouse is still using a type of optical sensor. The difference is that the optical mouse sensor uses LED light to track movement, whereas a laser mouse sensor uses laser light. An advantage of a laser mouse is that it works on almost any surface, including black and shiny surfaces. However, a laser mouse may have difficulty working on a tissue-like surface, whereas an optical mouse would function better.