By the change of environment, use sensory organs
The mantle is actually a liquid. The intense heat of the core of the Earth causes the mantle to move in convection currents.
The moon makes one full rotation around the earth every month (29.53 days). This means that it makes one 360 degree rotation every ~30 days, which is 12 degrees of movement per day.
Since the earth rotates once every day, so it makes one 360 degree rotation every 24 hours.
To determine how many 'hours' later 12 degrees is, do: 12 degrees / 360 degrees * 24 hours(in a day) = .8 hours, which if you multiply by 60 you get 48 minutes.