This human sundial is a fun outdoor STEM activity that will help kids understand how shadows are made and encourage them to experiment with light and shadow.
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Science was one of my least favorite subjects in school as a kid. Ironically, I actually love science itself, but much of the way science is traditionally taught (or at least how it was taught to me in school) sucks the life and wonder out of learning about how the world works.
But science isn’t boring!
I am determined to give my kids lots of hands-on opportunities to explore science in fun ways (i.e. – not just reading about it in books…much as I love books, they have their limitations). That means we do LOTS of experiments, STEM challenges, and activities to learn about the world around us.
Last week, we did a fun science activity exploring shadows: we made a human sundial!
We’ve done this experiment several times over the years, and it’s always a hit! It is extremely simple to do, and it opens the door to lots of other activities and observations about how light and shadows interact.
Want to make your own? Read on for step-by-step instructions for how to make a human sundial and explore shadows at home.
First things first…
What is a shadow?
Shadow: the dark figure cast upon a surface by a body intercepting the rays from a source of light. (Merriam-Webster dictionary)
Fun facts about shadows & light:
Share these with your kids before you get started to get them interested in the topic:
- It takes 8 minutes for the light from the sun to reach Earth. (source)
- Ancient Egyptians were making sundials over 2500 years ago! The oldest known sundial was found in the Valley of the Kings and dates to 1500 B.C. (source)
- The color of the sun (white) is actually the result of ALL the colors of the rainbow being reflected into our eyes at once. Black is the absence of all colors. (source)
Now, on to the experiment!
How to make a human sundial
What we’re learning:
- physics and astronomy (science of light/shadow & the effects of the sun on the earth)
- measurement (measuring the length of shadows and how they change)
- the scientific method (conducting an experiment)
- critical thinking skills (drawing conclusions from evidence)
- Open space with concrete or another hard surface (we’ve done this on our driveway and our back patio/sport court)
- a person
- sidewalk chalk
- a clock
- science notebook & tape measure (optional)
- Check the weather forecast to make sure it will be sunny all day when you do this experiment.
- Scout out an open area where you can mark your sundial. You’ll need to visit it several times during the day (I recommend at least 4 times), so you want it to be nearby. We made our sundial on our sport court in our backyard, but you could also use a driveway or patio.
- Draw a small circle (or make an X) on the ground to mark where your volunteer (child) will stand each time you measure his/her shadow. It’s important to stand in the same place each time to get accurate measurements. I traced a frisbee, and it made the perfect standing spot.
- Early in the day (we started at 10:00 AM), have your volunteer stand on the marked spot. My son also raised his arms up and clasped them above his hands so he was like the hour hand on a clock.
- Trace your volunteer’s shadow using sidewalk chalk & write the time next to it.
- Come back at regular intervals throughout the day & trace your shadow again, noting the time next to each tracing. We checked every hour because my son was really intrigued, but you could just do every 2-3 hours if you want. 9 AM, 12 PM, 3 PM and 6 PM would give you a good set of data to discuss.
- As you mark your shadows on your human sundial throughout the day, talk with your child & encourage them make observations about the shadows. Be sure to also point out the general position of the sun in the sky & how it changes throughout the day (note: remind kids not to look directly at the sun).
- Is it long or short?
- Is it wide or narrow?
- What direction did your shadow move since the previous tracing?
- How much did it move?
- At the end of the day, help your child draw conclusions from the data you have collected together. Consider the following questions together.
- Why do you think your shadow changed throughout the day?
- What affects your shadow’s shape?
- What did you learn about the relationship between the sun and your shadow?
More fun shadow activities to keep the learning going:
Sunlight demonstration: If you have a globe and a flashlight, use them to show kids how the sun (flashlight) shines on the earth making day & night as the earth rotates.
Shadow puzzles: Use toys to make shadows on a large piece of paper and trace the shadow. Take away the toys and see if your child can match the right object to its shadow.
Play shadow tag: Find a wide open space in the sunshine to play tag. One person is “it” and chases the others, trying to tag (or stomp on) the other players’ shadows.
Learn to make shadow puppets: Set up a light source from one direction (like a lamp or flashlight) facing toward a light-colored wall. Place your hand between the light and the wall, and notice the shadow it creates. This site will teach you all sorts of animals to make using just your two hands!
Books about shadows:
- “My Shadow” by Robert Louis Stevenson (poem)
- What Makes a Shadow? by Clyde Robert Bulla
- Moonbear’s Shadow by Frank Asch. I love this classic story about bear’s frustration as he tries to get rid of his shadow so it won’t scare the fish away. The end of the book is a great opportunity to discuss why the shadow finally “agrees” to stay out of the way (spoiler: because it’s later in the day and the sun has moved across the sky).
Want more fun summer activities?
This human sundial activity was created as part of our Summer Plan for Fun!
Follow me on Instagram to get daily inspiration for simple activities you can do with your kids to make this summer one to remember.
In the meantime, here are a few tried-and-true activities your kids will love: