The "Why do we need sunscreen?" Experiment

If your kids are like mine, they can’t stand it when you put sunscreen on them. I was so excited to find this activity from Sid the Science Kid to illustrate to kids exactly why they need to wear sunscreen!

We made a few blunders on our “experiment” but hopefully you’ll learn from our mistakes!

Here’s what you’ll need:  sunscreen (not the spray kind) and a black/dark blue piece of construction paper.

1. Fold a piece of black (or dark blue) construction paper in half.
2. Put a VERY SMALL dab of sunscreen on one side of the paper. This is where we messed up…we put WAY too much sunscreen on.
3. Let your child smear the sunscreen over ONE side of the paper (again, we messed up and Big Brother got it on both sides).
4. Put it in direct sunlight for most of the day (you’ll have to move it around a couple times to keep it in direct sunlight).
The paper after about 5 hours. Had we not had too much sunscreen, you would be able to easily see that the sunscreen kept the paper dark while the sun faded the side with no sunscreen.

Talk to your child about how sunscreen protects our skin just like it protected the paper. Some sunlight is good for our bodies (vitamin d, anyone), but too much is harmful. Without sunscreen, the sun would hurt our skin. Talk about other things that protect our skin from the sun (hats, buildings, clothing, shade, etc).

A helpful reminder for Big Brother is remembering back when I had the worst sunburn of my life back in March and how it hurt to even move…he prayed for my sunburn to feel better for about 6 weeks afterward!


  1. I remember one year one of the students did a science fair project with hotdogs and sunscreen and leaving them out in the sun. They weren't in my class so I don't really remember the details.

  2. VERY good idea! I'm so using it. Im having a skin cancer scare right now (nothing that can't be taken care of), and I want my fair skin ladies to always wear sunscreen so they don't have to go through things like this.

  3. I've done this before with my kids and they think it's neat. But what they really love to do, is take little items from around the house (magnetic letters, small toys with interesting shapes, pattern blocks, leaves, etc.) and put on a piece of construction paper (even lighter colors work well!) in direct sunlight. Leave for a few hours…come back, remove all the items and voila! You have pictures where all the trinkets once were. So fun!

  4. I will for sure try this sunscreen experiment at home. I have two red-haired, fair skin little girls who HATE it when I slab the sunscreen on. What a great illustration of why I make them endure it:) Thanks.

  5. Ooh! This looks fabulous! Unfortunately, I'm horrible at remembering sunscreen, and my kids have had a few too many sunburns :( so they know from personal experience how important it is to wear sunscreen, but this project looks like a great idea! I'll have to try it since our neighborhood pool is open now, and we'll be spending a LOT of our time there this summer!

  6. I am a terrible mom. No serious science experiments for me. I googled images of people with really bad sunburns and showed them to my kids (ages 7 & 4). They wear sunscreen without complaint now.

  7. I’m totally envisioning drawing a couple of faces on the dark paper so kids can compare the sunscreen person and the non-sunscreen person!

  8. This is cleaver I guess. But doesn’t really price any points. I guess if you dot in one place for 5 hours in the sun you may get burned. We are a sunscreen free family and will remain that way. Most sunscreen has ingredients in it worse then anything you would receive from the sun.

      1. Not necessarily Bonnie… What is the vitamin D3 level of the person with cancer? I know for a fact it will be low, as cancer is a sign of a body that is fighting against something which won’t happen if you have high vitamin D3 levels. If you burn quickly, that means you have a vitamin D3 deficiency. You can either get sun, or take a supplement and monitor your levels.

        I have to take 100,000 iu of liquid vitamin D3 to keep up levels of 70-80 ng/ml. Doctors will say you are good at 10-20 ng/ml, but that is still deficient. You want to be at least at 50 ng/ml, and 90-100 ng/ml if you are fighting cancer or other serious illnesses.

        I agree Amanda. Our family “eats our sunscreen” instead, and then we don’t have to apply anything with harmful ingredients ( Sunscreens have many harmful effects, since most rub all the way in, which means you are full of nanoparticles. Those have many serious side effects, including cancer… Some sunscreen ingredients (such as oxybenzone, benzophenone, octocrylene, or octyl methoxycinnamate) may be carcinogenic or have other health risks. You should be fully informed of the risks of sunscreen.

  9. We went to a Children’s museum where they squeezed out some sunscreen on a white t-shirt. You really couldn’t see it since it was white on white….but then they put the shirt under ultra violet light….Magical~! The sunscreen was black on the white t-shirt. I thought about using that in my Sunday school class and write the word sin or wrong doings….when you think nobody sees…it is still there.

  10. For our chem class, we have to do an experiment with pictures! Do you have any suggestions? We used baby sunblock 25 and waterproof 15!! The baby in the first experiment was spread on lightly and the other was thick. In this experiment, the baby lost. When we did it again, the baby was spread thick and it won!

  11. I doubt it is actually the suncreme that protects the paper – any oily liquid would keep / make the paper darker…. The idea in the comments ( to show the damage done by sunrays by placing objects in front of the paper which in their shadows changes less than in direct sunlight ) is a more scientific and truthful way to educate children on uv-rays…

  12. Just an FYI…while in theory this experiment has the possibility of showing the protective benefits of sunscreen, the example is NOT accurate. Construction paper is NOTORIOUS for bleaching naturally in the sun. In my kindergarten class we actually place various objects on a dark (black or dk. blue) sheet of construction paper and place it in the sun for the bleaching effect it has, leaving the “shadow” of the objects, much like photographic paper works.

  13. Even though it isn’t for the same scientific reason, I think this is a useful metaphor to show what sunscreen does for our skin. The sunscreen shields the paper from the bleaching effect like it shields our skin from the UV rays- in fact, the experiment wouldn’t work without using something that was affected by the sun to show that it isn’t as affected where the sunscreen was applied.

    I love this idea and I plan to use it in my preschool class. I’m also using it as an activity idea for a nutrition, health, and safety class (with appropriate citation, of course!) Thank you for the idea!

  14. I would have to agree that this experiment is in accurate because our skin does not have the same components of construction paper. My skin is super sensitive to sun screen products and I actually break out in hives and rashes ?

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