Jacklyn White, age 10, of Bridgeport, Conn

When you take a trip in a fast jet, you feel the speed only when you take off and coming for a landing  Then you fasten your safety belt to protect you from the push and pull of the moving plane  But during most of the journey, when the plane is flying fastest, you do not feel the movement at all  You can stand or walk around the floor of the plane as you would around the floor of a house on the ground  This is because we do not feel the movement of an even speed, We feel only the speeding up of acceleration ‑ or the slowing down of deceleration 

The world whirls around at an even speed  We do not notice the movement for the same reason that we do not notice the steady movement of a plane,

Nor do we notice the steady speed of the earth going around its orbit or the steady speed at which the Solar System whizzes through the Galaxy, But we would feel it if these speeds were slowed down or speeded up