Minecraft wiki entry for Experience, associated text: When collected, experience orbs make a bell-like sound for a split second. Unlike resources, experience points are picked up gradually: no matter how many orbs are in the range of the player, they are added to the player's experience one at a time (10 orbs/second). In extreme cases, this can result in the player being followed by a swarm of orbs for many seconds. If an experience orb isn't collected within 5 minutes of its appearance, it disappears.