# What does a sundial look like?

After a few hours, you should have seen that the sundial resembles a clock face, with the numerals equally spread around the plate. The shift in form and position of your shadow is caused by the Earth's rotation on its axis. The sun seems to travel across the sky as the Earth spins. When the shadow reaches the 12 o'clock position, the sun is at its highest point in the sky and shadows are longest throughout the day. At 3 o'clock, when the sun is at its lowest point, shadows are shortest.

The shape of the dial has some significance. If you look at a clock from the side, you'll see that it has numbers but no hands. This is because clocks use an hourglass to measure time. Sundials were used before clocks because they did not require electricity or any kind of battery. Clocks use springs and weights to keep time, while sundials use the movement of the sun to tell time.

Sundials work by having a clear glass disk called a "prism" attached to a stick called a "pendulum". As the pendulum swings back and forth, it reflects light onto the dial face. By measuring the length of each swing, you can work out how far the pendulum has swung and so know what time it is.

You can make your own simple sundial. All you need is a clear plastic bottle, some string, and a marker pen.

## What is the sundial attempting to teach us about the motion of the earth and sun?

As the sun appears to travel across the sky, so does the position of the shadow. This is why at any given time only one quarter of the sky is illuminated - because during a 24-hour period, the sun will have moved through all parts of the sky twice.

The motion of the earth around the sun causes day and night. During a single revolution of the earth on its axis, day and night occur once each year. Because the path taken by the sun during this annual cycle is not exactly perpendicular to the equator, we have seasons: summer and winter here on Earth. But we don't have seasons everywhere on Earth at the same time. For example, if you were standing on the north pole of Earth, there would be no change in the length of daylight in June compared to December. Here on the equator, where the sun is always directly overhead, there is constant daylight throughout the year.

Sundials have been used for centuries as tools for learning about gravity, the orbit of the moon, and other natural phenomena. Modern technology has also used sundials in spacecraft navigation equipment.

In conclusion, the motion of the earth around the sun is responsible for the daily cycle of light and darkness.

## How does a sundial work?

When the earth spins on its axis, the sun appears to "move" across the sky, casting shadows on things. A sundial has a gnomon, or thin rod, that casts a shadow onto a platform with different times inscribed on it. The observable movement of the sun varies on a daily basis due to the tilt of the earth's axis. But over the course of a year, the apparent position of the sun relative to the equator changes by about 10 degrees.

As the sun moves across the sky during a day, the appearance of its image on the gnomon changes. If we know how far apart certain parts of the image are, we can calculate when it will next be at one of those points, and so determine the time. Sundials have been used for thousands of years because they provide the best way to tell time during daylight hours. They are still used today in places where electricity is unavailable or expensive, such as rural Africa and Asia.

Gnomons were originally used in architecture to make sure that windows were placed toward the center of buildings to allow sunlight into interior spaces during the winter months, when no direct light could reach the floor. As telescopes became available in the 17th century, people began to use them to look at the night sky, too. Before telescopes, the only way to see objects beyond the horizon was by watching their reflections in the surface below.

##### Cindy Bennett

Cindy Bennett's journey started when she was 16 years old. She had a near death experience and it changed her life for the better. It showed her that we are all spiritual beings, and we should live our lives to reflect this truth. Her mission is to help others connect with their inner spirit through healing, spiritual development, meditation and yoga which she teaches in person or online at any time of day or night!