Let’s revisit shadows…
Last week we learned all about shadows. Shadows are made by blocking light. Light rays travel from a source in straight lines. If an opaque (solid) object gets in the way, it stops light rays from traveling through it. … The size and shape of a shadow depend on the position and size of the light source compared to the object. Today we are going to be looking specifically at shadows caused by the sun. We are going to start with out experiment first, because we are going to be following it throughout the day. At starting the experiment, we’ll learn how the position of the sun affects the shadows it produces.
Following the Sun: Crash Course Kids #8.2– Intermediate (3rd grade +++)
So the suns position in the sky changes throughout the day, but guess what, the suns not actually moving. We often say “the sun moves across the sky”, but what’s really causing the position of the sun to change is that the earth is rotating on its axis. It’s takes 24 hours for the sun to do a complete rotation. You’re right! 24 hours is a day! The sun rises in the east and sets in the west. But remember, it’s the earth that is moving, not the sun that is causing “the sun to move across the sky”.
STEAM Activity Ideas!
Catch Your Shadow!
Looking at our shadow at different times throughout the day definitely tells us that the position of the sun is changing. Did you know that’s it possible to catch your shadow?? All you need is a large parking lot or sidewalk and a piece of sidewalk chalk. Just like we looked at our shadow at different times of the day, you can “catch” your shadow by having someone trace your shadow. Each time, make sure your feet are in the same spot and your body should be in the same position. As they trace your shadow throughout the day, you will see it change both size and direction. Feel free to use a different colored piece of chalk each time, so at the end you have a rainbow of you:) and turn this STEM activity into a STEAM activity! Also, like in the picture, you can write the time.
Catch a Lion, or a Tiger, or a Bear, Oh My!
Watch it move!
So we know the sun’s position moves across the size because we see how our shadow changes. You can also tell because you can look at it. We all know though that we shouldn’t look directly at the sun, so you need to be careful. And neat (and safe) way to watch the sun “move across the sky” is by using time-laps photography. That is where a camera is set up and remains still, and it takes continuous pictures over a certain amount of time. Although it would take nearly 12 hours if you watched the sun go from sun rise to sun set, using time-lapse photography you can watch the whole process in just a few minutes. Take a look at the video below!
Make Your Own Sundial!– Everyone!
Now it’s time to use everything we’ve learned and discovered to make sundial. A sundial is like using the shadows a sun creates to tell time. This video will tell you all about sundials and then give you a lot of different ideas on how to make one. Our favorite is using a paper plate and a long skewer or chop stick. It’s important to make sure that the “12” on your clock is facing north and that once you put your sundial down you secure it so that it doesn’t move.