In today’s experiment, we’ll talk through an experiment that you can do with your child to help them understand what a sundial is, how it works, and talk about time.
What is a sundial?
A sundial is a device used to tell time by the position of the sun in the sky. The shadow cast by the sun moves across a dial, indicating the time of day. Sundials have been used for thousands of years and were one of the first timekeeping devices invented.
This is a great experiment to introduce your child to time measurement!
How to make the Time Travelers engineering experiment
Supplies you will need
For this experiment, you will need the following:
- A flat surface that receives direct sunlight
- Skewer (should be around 12″ tall)
- Paper plate
- Watch or a clock to check the time
Before you start
Kids LOVE timers! If your child has access to a timer, they may love to be the one in charge of setting the timer for each hour.
Here is how to do the Time Travelers experiment with your toddler:
Step 1: Choose your location
We want to find somewhere that receives direct sunlight while the sun is out and it needs to be on a flat surface. We chose our back patio, which is level and receives direct sunlight all day long.
Step 2: Set up your sundial
Puncture a small hole using your skewer in the middle of the paper plate. The skewer will serve as our gnomon, which is the part of a sundial that casts a shadow and tells us the time.
You may also choose to place something on or around the paper plate if it’s windy outside (don’t want it to fly away!). Since we set our plate on a metal table with holes in it, we used some magnets around the paper plate to hold it down.
We also made sure the skewer was inside one of the holes in the table to hold it in place.
Get your preschooler involved: Ask your child to help you set up the experiment! You can have them insert the pencil or stick, and even get their input about if the stick is straight or not.
Step 3: Tilt the gnomon
We want to account for the tilt of the Earth with our gnomon. Otherwise, your sundial will come out looking something like this:
Tilt your gnomon to the north to account for Earth’s tilt. It doesn’t have to be exactly 23.5 degrees tilted in order for it to work; just try to get as close as you can (for example: don’t tilt it down 45 degrees!). Here is how we tilted ours:
Step 4: Draw out the sundial
When you’re ready to start, mark the position of the stick’s shadow on the flat surface with a marker. This will be the starting point for the sundial. Write the time next to that mark.
Set your watch or timer for one hour after that, then head outside and mark the next position with your marker.
Repeat this step every hour until the end of the day. Your shadows should be moving in a circular pattern around the paper plate.
You have now created a sundial!
If your child wants to, you could even have them color each hour on the sundial with a different color crayon.
Step 5: Talk about it
Check the time on your watch or clock and compare it with the time on the sundial. You will notice that they may not match exactly. This is because the sundial uses solar time, which is slightly different from the time on your watch or clock.
The engineering behind the Time Travelers experiment
This experiment teaches:
- Understanding the concept of time
- Basic astronomy and the Earth’s rotation
- Hands-on engineering and problem-solving skills
How it works
The sundial experiment is a great way to teach your preschooler about the movement of the sun in the sky and how it can be used to tell time. The shadow of the stick moves in a circular pattern because the earth rotates on its axis, causing the sun to move across the sky.
The sundial uses solar time, which is based on the position of the sun in the sky. Solar time is slightly different from the time on your watch or clock, which is based on the rotation of the Earth around the sun.
Understanding the concept of time
Building and using a sundial introduces preschoolers to the concept of time measurement. With this experiment, we can teach them that time can be tracked and measured based on the position of the sun and the movement of shadows.
By observing how the shadow changes throughout the day, children begin to grasp the concept of time progression.
Basic astronomy and the Earth’s rotation
Through this sundial experiment, we can begin to introduce basic concepts of astronomy to our preschoolers.
They learn that the sun appears to move across the sky from east to west, causing the shadow to shift accordingly.
This is a great opportunity to talk to our kids about how the Earth rotates on its axis! You could even use a globe and a small ball (the Sun) to demonstrate this.
Don’t have a globe? No problem! You could use a standard ball and use the point where you inflate the ball as the axis of the Earth.
Hands-on engineering and problem-solving skills
Building a sundial involves problem-solving and basic engineering principles. Preschoolers need to align the dial accurately, position the gnomon (our skewer) correctly, and observe how the shadow falls on the dial.
This hands-on experience encourages critical thinking, spatial awareness, and fine motor skills development as they manipulate and position the materials to create an effective sundial.
More outdoor engineering experiments to try out with your child
- Go Fly a Kite! Build your own kite and see if it flies!
- Bubble Bonanza: Build a bubble machine with just a few supplies!
Take a look outside for me, would you? Is it a windy day? If so, let's teach our kids how to build a kite and how kites fly! Building a kite teaches your child about engineering and physics, but...