Why can you see something before you hear it? Today's reading compares the speed of sound to the speed of light. Light travels faster than sound. This video is a great example. The person with the camera was 10 miles away from the launch of the Space Shuttle. They could see the Space Shuttle launch immediately as it happened because light travels so fast. But since sound travels about 1 mile in 5 seconds, it took about 50 seconds for the sound of the launch to travel to their ears.
Here's another example created by someone using a video game. A rocket is launched at the ground far away. You can see the explosion before you hear it.