More experiments on light

We have had a wonderful long and sunny summer this year. This also meant we were able to continue with light experiments. As I have previously said somewhere, going back to topics already covered is a great way to refresh the topics in mind and deepen understanding and learning. Previous light experiments can be found here. This time we looked at sunlight. Previous experiments with sunlight can be found here. This time we reflected it and created a sundial. Finally I also found some gummy bears and we looked at how laser is absorbed in different coloured gummy bears.

Firstly we reflected sunlight. Needed for this experiment is a sunny day, a wall with some stripes and a hand held mirror. I asked her to pick up the mirror and reflect sunlight onto the wall in shade. It took her awhile to find the light and figure out how to reflect it, but she persevered and succeeded. She played with it awhile and then I asked her to see if she could follow the stripes in the wall with the light. This was easier and quickly done.

An image of a child holding a mirror and reflecting sunlight onto a wall

Success! Sunlight found and reflected with a mirror onto a shady surface. In this image daughter is following the stripes in the wall with the light

Our second experiment was to work with shadows. We took two of her toys and placed them on the ground. Then we drew the outline of their shadow onto the ground. We then also observed what happened to the shadow when a cloud covered the sun for a bit. Of course the shadow is diminished, because there is less light, so the contrast is far less clear.

A picture of two my little ponies in sunlight with the outline of their shadows drawn on the ground

Shadow drawing. The picture is taken a bit later than when I drew the shadow created by Cadence and around the time we drew the other one.

On the next day we drew a sundial of my daughter. We drew the first one in the morning after breakfast, two during the day, and the last one a bit before it was time to go to bed (below). On the next day on the beach we built solar clocks in the sand with sticks and rocks to measure the time we were at the beach. Little sister kind of demolished each one, but still building them showed me that older sister had understood what we did.

Four outlines of daughter drawn at different times in one day demonstrating the way Earth revolves around itself causing the sun to shine from different directions.

Four outlines of daughter drawn at different times in one day demonstrating the way Earth revolves around itself causing the sun to shine from different directions.

After the sundials, we played a game of shadow tag. In this game one does not need to capture the person, but step in their shadow. This was great fun and daughter would have played it for far longer than my lungs and legs allowed. It does require a somewhat different strategy to avoid being touched than avoid having your shadow touched.

Inside we refracted light with a CD. I mentioned this option in the previous post about experimenting with light. For this you need a CD (or a DVD), a flashlight, and a dark room. The room does not have to be pitch black. As you can see in the image below, the CD already shows the different wavelengths of light from the light source in the hall. So basically, this can be done without a flashlight.

Separating light wavelengths with a CD

Necessary items: flashlight, a CD (or DVD) and a dark room

Once in the darker room, place the CD on the floor or table and turn the flashlight on and towards the CD. The CD will reflect the light onto the wall as white light, but because there are small grooves on the surface of the CD, some light is reflected back to us at an angle showing us the different wavelengths of light. For a child of 5-years old I explained this as saying that the white light I shone towards the CD contained all these pretty colours and because the surface of the CD is uneven, we get to see all of them as they are reflected back to us.

Separate wavelengths of light with a cd

The CD reflects the light onto the wall and because of the small grooves on the surface it also reflects the wavelengths seen in different colours back to us.

Finally in light experiments I finally was able to try something out I could not the last time we did these experiments. I bought some gummy bears and shone a red laser through them (image below). In green gummy bears the light is dim and stops after the fourth gummy bear. In the red ones, the red laser lights up the first three and can be seen in the fifth one still. This is due to the wavelength of those colours. Red passes on red light far better than green passes on red wavelengths.

Experimenting light absorption with laser and gummy bears. As shown, red laser is absorbed far more in green gummy bears than in red ones. This is because the red already reflect red wavelengths so they pass those on far better.

Experimenting light absorption with laser and gummy bears. As shown, red laser is absorbed far more in green gummy bears than in red ones. This is because the red already reflect red wavelengths so they pass those on far better.


If you try these experiments at home and your child asks questions, please let me know what types of questions they ask in the comment section so I can further develop these instructions. If you have questions about these experiments or instructions, leave me a comment and I will answer and also improve these instructions. Also, please remember like and share if you find this useful.

Copyright text and images: Satu Korhonen. You are free to try these experiments out, use them in your teaching. But instead of copying the text or images, link back to this page.

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