Make a Sundial and Go Back in Time
Sundials were used to tell the time before people had watches or clocks. A sundial is a device that tells the time of day by the position of the Sun. In common designs such as the horizontal sundial, the sun casts a shadow from its style onto a surface marked with lines indicating the hours of the day. The style is the time-telling edge of the gnomon, often a thin rod or a sharp, straight edge. As the sun moves across the sky, the shadow-edge aligns with different hour-lines. A sundial works by casting a shadow in different positions, at different times of the day.
Solar Eclipse and Lunar Eclipse
A solar eclipse occurs when the moon passes in a direct line between the Earth and the sun. The moon's shadow travels over the Earth's surface and blocks out the sun's light as seen from Earth.
A lunar eclipse can occur only at full moon. A total lunar eclipse can happen only when the sun, Earth and moon are perfectly lined up — anything less than perfection creates a partial lunar eclipse or no eclipse at all. The Lunar eclipses occur when Earth's shadow blocks the sun’s light, which otherwise reflects off the moon.