Just how soon does night fall after sunset?

You must have noticed that even after the sun sets the sky does not get dark right away. The reason for this is the curve of the Earth. The rays of light continue to come through the atmosphere even after technically the sun has set. So have you ever wondered just how soon does it become pitch dark after sunset?

Here is an interesting science experiment that can be done.  You will need to measure the time from when the sunsets to the time it becomes totally dark. This period of semi light is also known as twilight. It has nothing to do with Bella and her favorite vampire, its just the term from which the saga took its name.

So how does one measure twilight and make a science project out of it? You will have to take the length of time that it takes to turn day into night at different times during the year. You can start with measuring twilight for a week each month. Then take the average of the week for that month’s twilight duration.

Repeat the process each month and at the end of the year you will have the duration of twilight in each month. Now you can get the yearly average figure as well. You can make charts with graphs showing the 12 month readings for the duration of twilight in the year for the display board. An interesting and interactive science project.