Sunscreen - Does it make a difference?

Scout did a science project this year -

Sunscreen - Does it Make a Difference?

 

We purchased some UV sensitive paper and wiped 3 kinds of sunscreen on them, one for each strip. 

We left it out in the sun for almost 20 minutes and checked our results.

We placed a coin on one of the strips as our control. 

 The coin would be an example of if you wore a swim shirt to cover up with instead of putting on sun screen.

The top strip had spf25 of a non-waterproof sunscreen made by Clinique.

The second strip was spf25 non-waterproof made by origins.

The bottom strip was spf100 waterproof and sold in a big bottle.

After one minute, 20 seconds.   We had also put it on in different levels.  Less towards the outside, and more towards the center, to see if amount of sunscreen applied made a difference.  You can see the blue paper where the sunscreen is dry, and where it looks more white is where the sunscreen is still moist. 

It appears at this point, all three work exactly the same.

 After 2:39 it looked like this.  Seems that each one worked the same, And it appears that we may have rubbed some of the UV solar paper off with the moisture of the sunscreen...that's why it isn't so blue as the edges. 

We decided to keep going to see if there were any major changes with time.  After almost 20 minutes there was a lot of black.  Not quite sure what was going on there. Something either with the UV paper or the sunscreen reacting.

In the end - we took off the coin and compared it to the rest of the paper.

YOU be the Judge!!

 

As a Floridian, I can tell which friends of mine have pools and which don't.  Those with pools all know to send your kid out swimming and playing with a swim shirt on (rashguard) not sunscreen.  We know that sunscreen just washes off within the first 20 minutes anyway, and clogs the pool filter, scums up the water, stains the side tiles, and creates a slippery deck because it leaves a slippery film on your body after it touches the water.  Unless you put it on an entire half hour before swimming, so it is completely dry and soaked into your skin, it just washes away as soon as you get in. If your body feels soft and moist like you just put lotion on, it's not soaked in enough. 

 

We always use a swim shirt, long sleeve if possible, and for our legs and faces we apply the sunscreen before getting in the car to go to the beach.  That way - when we get there and the kids want to run, they can!  We reapply the sunscreen after an hour of swimming in the ocean.  It's always washed away by then.