Special relativity deals with the laws of physics in inertial (non-accelerating) reference frames, while general relativity includes the effects of gravity and acceleration on space and time.
According to Einstein's theory of special relativity, the speed of light is constant for all observers, regardless of their relative motion. This is because the laws of physics should be the same for all observers in inertial reference frames.
In special relativity, time and space are relative concepts, meaning they are affected by an observer's relative motion. General relativity goes further by showing that gravity also affects the curvature of space and time. This results in phenomena like time dilation and gravitational lensing.
One example of relativity in action is the Global Positioning System (GPS). The satellites in the GPS system use special relativity to accurately measure time, while general relativity is used to account for the difference in gravitational pull at different altitudes.
While a strong understanding of mathematics is helpful in fully comprehending relativity, it is possible to understand the basic concepts and principles without advanced math skills. Many resources, such as books and videos, provide explanations of relativity in a more accessible way for non-experts.