How long does it take for Earth to complete one full rotation (one full spin)?
AOne year (365 days)
BOne month (about 30 days)
COne day (24 hours)
DOne hour
Earth completes one full rotation -- one complete spin on its axis -- every 24 hours. That is one day. One rotation gives us one cycle of day and night. Do not confuse this with Earth's orbit around the sun, which takes one year (365.25 days). Rotation is the daily spin; orbit is the yearly trip around the sun.
Question 2 True / False
We can seldom feel Earth spinning because it has stopped rotating.
TTrue
FFalse
Answer: False
Earth has not stopped -- it is spinning right now at about 1,670 kilometers per hour at the equator. We cannot feel it because the rotation is smooth and constant, and we are spinning along with everything else (the air, the oceans, the ground). It is the same reason you do not feel the motion when riding in a car or plane at constant speed -- you only feel changes in speed or direction, not steady motion.
Question 3 Short Answer
Explain why the sun appears to rise in the east and set in the west, even though it is Earth that is moving.
Think about your answer, then reveal below.
Model answer: Earth rotates from west to east. As your location spins toward the east, the sun comes into view on the eastern horizon -- that is sunrise. As Earth keeps spinning, you move past the sun and it appears to cross the sky. Finally, your location spins away from the sun and it disappears below the western horizon -- that is sunset. The sun is not moving around us; we are spinning past it.
This is the same illusion as watching trees appear to move backward from a car window. We are the ones moving, but from our perspective on the spinning Earth, the sun appears to move across the sky from east to west.