Which is more effective - turning the head or staying still? Why? Why is it harder with an earplug in one ear? How do the animals can turn their ears have a further advantage? How does vision work in concert with the sense of balance? Can you see why people are asked to walk a straight line to test sobriety? How is it that, even with your eyes closed, you know whether your arms are extended directly in front of you, up over your head or down at your side, bent at the elbow or straight, with palms facing up or down? Do you think this is affected by gravity or not? Would an astronaut in zero gravity and in pitch darkness know? Can you touch your nose with your eyes closed? Why does staring at a fixed point on the horizon rather than the fastmoving terrain sometimes help to reduce motion sickness? Why is zero gravity nausea inducing for most people?