system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does reading in a car make me feel sick, but reading on a plane/train not affect me?
gpt
Because planes and trains are much smoother rides. Motion sickness occurs when there's discrepancy between the  movement you're feeling in your inner ear and the movement you're seeing with your eyes. Cars bounce around a lot, causing you to feel a lot of movement that you don't see if you're reading.