Using the Sun to Tell Time

Illustrations via Tanglewood Hollow

Homeschool homework

Even with homeschooling there are evenings that we are still plugging away at homework needed for the following day. Sometimes not all work gets finished during the classroom time, so the evening studying and completing is needed so that we don't fall behind. It's important to have a good schedule and curriculum, so the homeschool classroom stays on task and also teaches good skills in staying productive.

Sundial Creation

A sundial is an easy and simple way to tell time just by using the sun. The sun as been an accurate timekeeping device for centuries and you can create your own. The earliest sundial was used was named "shadow clocks" and was used as early as 1500BC. Most recordings of sundial usage was done by the early Egyptians and Babylonians and they used forms of astrology to keep time. Sundials were used long before analog and are quite impressive to see the time changes as the sun moves across the sky. Here's how it's made...

What you'll need:

1. A straight piece of metal or wood. (We used a short length of rebar)

2. 12 large stones, 12 medium stones, and 12 small stones

3. String or measuring tape

4. A watch

What to do:

You need to find a clean, flat surface of ground that is sunny and clear off the area of any large debris, sticks, twigs, leaves, grass, and/or other items. Make sure the area is flat, and if there's slopes or grooves, rake the area clean and get it as level as you can.

Next, Hammer your piece of metal, or wood into the ground where you want the middle of the sundial to be. We used a rake and cleared the area and then raked in a circle for aesthetics. 

Next, tie your string to your middle piece and stretch out. Your sundial can be as big, or as small as you like. We wanted a bigger one, so we adjusted accordingly. Take your string around your middle stick and go around in a circle. As you go mark areas of your sundial that you need to either make bigger or smaller. You want to make sure your circle is even all the way around.

Once you've made your circle even all the way around, next you want to mark your time for that moment. Example: If you're doing this project at 1:00 p.m., the sun should cast a shadow on your middle piece onto a spot on your sundial. Place a large stone at that mark on the outer edge of your sundial. Then, set your timer and head back out to place your stone for 2:00 p.m. and so on. For the morning times, start at 7:00 a.m. and place a large stone for 7:00 a.m. Go back every hour and place large stones on the appropriate times. By the end of 24 hours you should have enough large stones in place to finish your dial. Estimate where the remaining large stones should be. 

Next, place medium stones between the large stones on your dial. These medium stones will be the marks for the half hour. Example: Place a medium stone between the 1:00 p.m. and the 2:00 p.m. larger stones. 

Finally, place the smaller stones inside the outer ring of stones between each medium and large stone. These will be the marks for the 15 minute time intervals. Example: Place a small stone between 1:00 p.m. and 1:30 p.m., as well as between 1:30 p.m. and 2:00 p.m. 

Continue around your entire dial and you're done!

Keep in mind that the shadows that are casts against your middle object will change throughout the year and from season to season. In the summer, when we did this project, the shadows were shorter. But, in the winter, the shadows cast will be longer. Although the days in winter are seems shorter, the shadows from the sun will be longer shadows. You can learn more about the shadows and sundials here.

A.M. stands for "ante meridiem," which means before noon and the P.M. stands for "post meridiem," meaning after noon. All time equivalent is before the noon hour or after the noon hour.

Side Note: Be sure to wear gloves while clearing a space for your sundial. We are all nursing a few blisters from our hard work. It was worth the effort, though, because our sundial is large and in a space where we can look at it often.

And, thanks to this guy for helping us lay everything out.