Telling Time with the Sun

One of the most interesting ways that humans have used the sun over the years is to tell time. You’ll find two projects that focus on creative ways of telling time in my Summer Solstice book, but here are two more ways you can explore this idea.

Make a Sundial

Shadows are the shortest they will be all year on the Summer Solstice which makes it a practical and fun time to make a sundial. You’ll need something to serve as the “gnomon” which is the the piece that casts the shadow, and then you’ll need something to record the position of the shadow every hour on the hour. We are using rocks here, but you can use whatever you want/ have available.

Materials:

• rocks (or some other object of your choice)
• a straight stick or bamboo
• paint markers (optional)

Method:

Early in the morning find a clear spot with lots of sun and few obstructions. Stick your gnomon (branch or bamboo rod) into the ground so it stands as close to straight up and down as you can manage.

Each hour on the hour, place a rock at the end of the shadow cast by the stick. As the day goes on you’ll start to notice a predictable pattern and can start hypothesizing where the next hour will fall. Keep this up until it gets too dark to see a clear shadow.

Congratulations you have made a functional sundial! You can leave it up and use it to tell approximate time all summer!

Telling Time with your Hand

This is a fun way to estimate how many hours are left until sunset. It could even turn into a fun counting game for a younger learner! Important: don’t ever look directly at the sun, look just below it.

On a sunny day, find a relatively flat place with few obstructions (like trees or buildings. ) Hold your hand out flat with the palm facing you and line your index finger up with the bottom of the sun.

Stack your other hand below the first one until your hand touches the horizon line. Count the number of hands it takes to get from the bottom of the sun to the horizon line– this is how many hours of daylight (approximately) are left. For example, if there are four hands, then there are four hours of daylight left.