Dermatology is the study of our skin, which is the largest organ in our body! Dermatologists help us take care of our skin and treat things like rashes, acne, and other skin conditions.

I wanted to know if SPF matters when you buy sun block.  For example, does a CVS brand 30 sunblock work better than a CVS brand 15 sunblock?  I also wanted to know if higher priced sunblock works better than lower priced sunblock of the same SPF?  My hypothesis was that the higher the SPF the better it would protect and that higher priced sun block would work better than lower priced.  

Does the SPF number on your sunblock actually matter? You apply four sunblocks with different SPF ratings to a clear report folder. Then you place light-sensitive developing paper underneath and expose it to sunlight for five minutes. The paper turns lighter where sunblock blocks more UV light.

The results are surprising. The SPF 4 section sometimes blocked more light than the SPF 30 section. Thicker, more even coats blocked more UV regardless of SPF rating.

A second test compares sunblocks at different price points but the same SPF. The thickest sunblock performed best. Price alone did not predict protection.

Title:  Do Different SPF's Make A Difference When Using Same
        Brand Sunblock?  Does Price Affect The Way Sunblock
        Works? 

Grade:  7 

I.  Statement of Purpose and Hypothesis: 

I wanted to know if SPF matters when you buy sun block.  For 
example, does a CVS brand 30 sunblock work better than a CVS 
brand 15 sunblock?  I also wanted to know if higher priced 
sunblock works better than lower priced sunblock of the same 
SPF?  My hypothesis was that the higher the SPF the better it 
would protect and that higher priced sun block would work better 
than lower priced.  

II.  Methodology: 

For the first part of my project, I bought four types of CVS 
brand sunblock.  Each of these sunblocks had a different SPF.  
The different SPF's were 30, 15, 8, and 4.  I also bought a pack 
of developing paper at a local photography store and 4 clear 
plastic report folders.  I then got some distilled water and a 
dish pan.  I asked my science teacher for sodium thiosulfate.  
The first thing I did was divide the report folder in 4 equal 
squares using masking tape.  I then labeled each sun block 1, 2, 
3, or 4.  I labeled each square 1, 2, 3, or 4.  I then applied 
the numbered sunblock to the appropriate square.  I put the same 
amount of sunblock on each square making it as even as possible.  
After I put the sunblock on, I dimmed the lights very low.  I 
carefully took out a piece of developing paper, making sure to 
close the case afterwards to keep the light away from the other 
sheets.  I put the developing paper, glossy side up, inside the 
report.  I then quickly took it outside on the driveway where it 
was very sunny.  I left it there for exactly 5 minutes.  While 
it was in the sun I made the mixture of the sodium thiosulfate 
and distilled water in the dish pan.  When the 5 minutes was up 
I brought the report folder back inside to the semi-darkened 
room.  There I carefully took out the developing paper from the 
report folder and layed it glossy side down in the mixture for 
three seconds.  Then I immediately rinsed it with cold water and 
let it dry for 15 minutes.  When it was dry I observed it.  
For the second part of my experiment I did the exact same thing 
except I used the sun blocks that varied in price, but had the 
same SPF.  


III.   Analysis of Data: 

On the developing paper, the sunblock which allowed the least 
amount of sun to penetrate, turned the whitest.  When I observed 
the data from my first experiment I was very surprised at what I 
saw.  I noticed that the SPF 30 sunblock was darker than the SPF 
4 sunblock.  This was very strange because I surely thought that 
30 was better than 4.  What I then saw was that in some places I 
had put more sunblock on the number 4 square than others, also 
the places where I had put more sunblock were the lightest and 
where I hadn't put much on it was the darkest.  For trial one 
SPF 4 was the best, then SPF 8, then SPF 15, and last SPF 30.  
For trial two, SPF 8 was the best, then SPF 4, then SPF 15, and 
last SPF 30.  

For the second part of the project my results were not as 
strange, but were not what I expected.  For trial one, "Bain de 
Soliel", which was the highest priced, worked the best.  "Banana 
Boat", which was the least expensive, was second.  "Bio Sun", 
the second highest priced was next, and then the second lowest 
priced, "Neutrogena" came in last.  

IV.   Summary and Conclusion: 

I was very surprised when I saw the results of 
both tests.  They did not agree with my hypothesis at all.  For 
the first experiment, it seemed to me that it did not matter 
what SPF you used, but how much you put of each one.  That is 
why I think SPF is irrelevant, if you put a lot of sunblock on 
and keep reapplying it.  

For my second experiment, I think it mattered how thick the 
sunblock was.  Bain de Soliel was the thickest and then Banana 
Boat.  But Neutrogena which came last was not thick and was very 
light.  So, for my second experiment, I feel price does not 
matter, but thickness does.  

V.   Application: 

I can apply the results of this experiment in many ways to my 
life now.  I now know I can use any type of sunblock and the SPF 
will not matter.  I will just have to remember to put a lot on 
and keep reapplying it.  I also know that if I buy a sunblock 
and it has a thin texture to find another brand.  These results 
can be critical for many people.  With the depletion of our 
ozone layer, skin cancer is a common problem.  People need to be 
aware of the SPF confusion and be informed about thick 
application of sunblock to prevent the damaging effects of the 
sun. 


SPF Ratings vs. Sunblock Thickness

Do different types of sunblock have different protection strengths?

<h1><strong>1000 Science Fair Project Ideas by Subject</strong></h1><p>Looking for a science fair project idea? Each of our science fair project idea has complete instructions with video. Get ideas for your science projects, find extra resources for your class' scientific projects, or try a fun experiment at home! It doesn't matter what grade you're in, there's something for everyone!</p><p>You can find your perfect science fair project from the different science subjects below or from our <a href="https://www.all-science-fair-projects.com/category0.html#bottom">science fair project idea lists!</a></p>

<h2>Science Fair Project Idea Lists</h2><p>Looking for other ways to find good ideas for science fair projects? Check out these lists of science projects!</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><h3>Easy Science Fair Projects</h3><p><img src="/images2/flex/176_popular 2 (2).png" data-size="100" data-float="left" style="width:100px; float:left">Explore the exciting world of science with an easy science fair project that you can do at home using simple materials. Any one of these easy project ideas will teach you important scientific concepts and help you have fun while learning. An easy science fair project is a great way to introduce the wonders of science to kids and adults alike!</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><ul><li><p>Changing the Color of Flowers</p></li><li><p>Baking Soda Volcano</p></li><li><p>Swimming Raisins</p></li><li><p>Egg in Vinegar</p></li><li><p>Color of Skittles Experiment</p></li><li><p>Jumping Rice Krispies</p></li><li><p>Mixing Colors of Light</p></li><li><p>Camouflage and Hide</p></li><li><p>Light and Dark on Seed Germination</p></li><li><p>Make a Parachute</p></li></ul><p>More science project details at <a href="https://www.all-science-fair-projects.com/science_fair_project_list/12">Easy Science Fair Projects <strong>→</strong></a></p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><h3>The Top 10 Best Science Fair Projects</h3><p><img src="/images2/flex/177_popular 2 (3).png" data-size="100" data-float="left" style="width:100px; float:left">To find the best science fair project for you, we've picked the best science projects from 10 different science categories, all with very interesting topics. If you're looking for more science projects at another difficulty level or topic, you can explore science fair project ideas by grade level at the top of this page!</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><ul><li><p>Jet Lag in Hamsters (circadian rhythm, Biology science fair project)</p></li><li><p>Egg with Vinegar (acid-base reaction, Chemistry science fair project)</p></li><li><p>Galileo's Inclined Plane Experiment (acceleration, Physics science fair project)</p></li><li><p>Plant's Favorite Color for Photosynthesis (Photosynthesis, Botany science fair project)</p></li><li><p>Color and Taste (color perception, Psychology science fair project)</p></li><li><p>Does Dog Saliva Kill Bacteria? (antibacterial, Microbiology science fair project)</p></li><li><p>Decomposing Plastic Spoons (biodegradable materials, Environmental Science science fair project)</p></li><li><p>Super Hero Egg Shells (structural engineering, Engineering science fair project)</p></li><li><p>Music Math: Playing Notes with Equations (music, Math science fair project)</p></li><li><p>Temperature's Effect on Seawater (climate change, Earth Science science fair project)</p></li></ul><p>More science project details at <a href="https://www.all-science-fair-projects.com/science_fair_project_list/13">Best Science Fair Projects <strong>→</strong></a></p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><h3>Cool Science Fair Projects</h3><p><img src="/images2/flex/178_popular 2.png" data-size="100" data-float="left" style="width:100px; float:left">Get ready to be amazed by super cool science projects that you can do right at home! With just a few simple things, you can be fascinated by science and have tons of fun with these popular science projects!</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><ul><li><p>Explosive Elephant Toothpaste</p></li><li><p>Egg in Vinegar</p></li><li><p>Electrifying Lemon Battery</p></li><li><p>Making Oobleck: Liquid or Solid?</p></li><li><p>Egg Drop Project</p></li><li><p>Colors of Skittles Experiment</p></li><li><p>Cloud in a Bottle</p></li><li><p>Baking Soda Volcano</p></li><li><p>Egg in a Bottle</p></li><li><p>Plastic Milk</p></li></ul><p>Project details and more cool science projects at <a href="https://www.all-science-fair-projects.com/science_fair_project_list/1/Popular_Science_Experiments_At_Home">Popular Science Fair Projects <strong>→</strong></a></p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><h3>One-Day Science Fair Project Ideas</h3><p><img src="/images2/flex/172_popular 2 (1).png" data-size="100" data-float="left" style="width:100px; float:left">Quick experiments can be a great option for a science fair project. In this list, we've highlighted one-day science fair project ideas for elementary school (easy), middle school (medium), or high school (hard). These experiments are fast and easy to do, but the science topic packs a punch!</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><h4>Acid-base reactions: Mixing acids with bases quickly makes carbon dioxide gas!</h4><ul><li><p><a href="https://www.all-science-fair-projects.com/project830.html"><strong>Rocket Film Canisters (easy) </strong></a>Make a rocket fly sky high with just baking soda and vinegar!</p></li><li><p><a href="https://www.all-science-fair-projects.com/project829.html"><strong>Make Your Own PH Indicator (medium) </strong></a>Learn how to make your own acid-base indicator using red cabbage and use it to test different fluids!</p></li><li><p><a href="https://www.all-science-fair-projects.com/project1327.html"><strong>Testing Antacids (hard) </strong></a>Find out which antacid can neutralize the most acid and get relief from heartburn and gastritis!</p></li></ul><h4>Chromatography reactions: Separating out colors as liquid moves through the paper!</h4><ul><li><p><a href="https://www.all-science-fair-projects.com/project826.html"><strong>Colors of Skittles Experiment (easy) </strong></a>Did you know that some Skittles have a secret rainbow hiding inside them?</p></li><li><p><a href="https://www.all-science-fair-projects.com/project678.html"><strong>Uncovering Fall Colors (medium) </strong></a>Have you ever wondered why leaves change color in the fall? Let's find out by using chromatography to separate the colors of a green leaf!</p></li></ul><h4>Heat reactions: Heat speeds things up!</h4><ul><li><p><a href="https://www.all-science-fair-projects.com/project274.html"><strong>Which Candle Burns the Fastest? (easy) </strong></a>Do you want to find out which color candle burns the fastest?</p></li><li><p><a href="https://www.all-science-fair-projects.com/project1291.html"><strong>Fire-Resistant Balloons (medium) </strong></a>Ever wondered if a balloon filled with water can withstand fire?</p></li><li><p><a href="https://www.all-science-fair-projects.com/project475.html"><strong>Can Peanuts Heat Water? (hard) </strong></a>Have you ever wondered if peanuts have enough energy to heat up water?</p></li></ul><p>Project details at <a href="https://www.all-science-fair-projects.com/science_fair_project_list/15/Quick_Science_Fair_Projects_You_Can_Do_In_A_Day">Quick Science Fair Projects →</a></p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><h3 style="text-align: start"><strong>Testable Questions for Science Projects</strong></h3><p><img src="/images2/flex/173_popular 2.png" data-size="100" data-float="left" style="width:100px; float:left">A testable question is a question that we can answer through a science experiment. To do this, we do a control experiment, then we change one thing in the experiment to see how it affects what happens. This is how we can discover the answer to our question!</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><ul><li><p>What makes a cloud form?</p></li><li><p>Can drink and food taste different just by changing its color?</p></li><li><p>Does the color of light affect photosynthesis?</p></li><li><p>Does temperature affect seed sprouting?</p></li><li><p>What makes popcorn pop?</p></li></ul><p>More <a href="https://www.all-science-fair-projects.com/science_fair_project_list/14">testable questions with their science projects <strong>→</strong></a></p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><h2>Science Fair Project FAQ</h2><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><h3>What are some hands-on ways to find inspiration for my science fair project?</h3><h4>Science museums</h4><p><img src="/images2/flex/124_7.png" data-size="100" data-float="left" style="width:100px; float:left">Science museums are great places to explore if you're looking for inspiration for your next science fair project or just want to learn more about science. Science museums, natural history museums, space museums, and discovery museums are all great places to do that! You can discover all sorts of interesting things about science and find cool project ideas for science fairs.</p><p>There may be free admission days or free passes to a science museum near you! Check your credit card for offers, your local library for free museum passes, and nearby science museums for free entrance days.</p><p>So what are you waiting for? <a href="https://en.wikipedia.org/wiki/List_of_science_museums">Find a science museum near you</a> and prepare to be awed by all that you can learn there!</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><h4>Look around and observe</h4><p><img src="/images2/flex/117_5.png" data-size="100" data-float="left" style="width:100px; float:left">Do you know how scientists start their cool projects? They often look around and notice things that are interesting or make them curious. Then they start doing an experiment! You can do the same! Look around your school, home, or community. Is there anything that catches your attention and makes you curious? Maybe you notice something interesting or a problem that people are facing. This could be a great starting point for your science fair project!</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><h4>Try an Easy Science Project!</h4><p><img src="/images2/flex/144_easy square.png" data-size="100" data-float="left" style="width:100px; float:left">These science projects are easy and fun to do. You may discover a simple experiment that sparks your interest and inspires you to do more experiments, turning it into a science fair project! Check them out at <a href="https://www.all-science-fair-projects.com/science_fair_project_list/12">Easy Science Fair Projects <strong>→</strong></a></p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><h3 style="text-align: start"><strong>How do I start a science fair project?</strong></h3><p><img src="/images2/flex/199_science coach.png" data-size="100" data-float="left" style="width:100px; float:left">No matter if you're in high school, elementary or middle school, science fair projects are a fun and unique way to discover science by asking a question and doing a science project. We'll help you find a science fair project idea and guide you through the process of doing and presenting your science fair project with <a href="https://www.all-science-fair-projects.com/science_fair_projects_coach/science-project-coach.html">Science Fair Coach's Science Fair Project Guide</a>.</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><h3>What should I do after I have a science fair project idea?</h3><p><img src="/images2/flex/143_intro science fair.png" data-size="100" data-float="left" style="width:100px; float:left">If you have a science fair project idea, Science Fair Coach can help you turn it into a full science fair project! Starting at the <a href="https://www.all-science-fair-projects.com/pgpage/4">Introduction to Science Fairs</a>, check out the section on <strong>How to do a science fair project</strong> for a step-by-step guide!</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><p><img src="/images2/flex/203_compared to scientific method.png" data-size="100" data-float="left" style="width:100px; float:left">We'll guide you through every step of the <a href="https://www.all-science-fair-projects.com/pgpage/5">scientific method</a>, from designing and conducting your experiment to collecting and analyzing your findings.</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><p><img src="/images2/flex/202_engineering design process.png" data-size="100" data-float="left" style="width:100px; float:left">If you're working on an engineering project, you can head over to <a href="https://www.all-science-fair-projects.com/pgpage/9">The Guide to the Engineering Design Process</a>.</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><p> <img src="/images2/flex/150_science fair poster.png" data-size="100" data-float="left" style="width:100px; float:left">Finally, we'll help you showcase your results on a <a href="https://www.all-science-fair-projects.com/pgpage/7">science fair board</a> for others to learn from and enjoy.</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><h3 style="text-align: start"><strong>How do I make a science fair board?</strong></h3><p style="text-align: start"><img src="/images2/flex/150_science fair poster.png" data-size="100" data-float="left" style="width:100px; float:left">Your science fair board is where you show off your science fair project for everyone to see and learn from. With <a href="https://www.all-science-fair-projects.com/science_fair_projects_coach/science-project-display-board-6a.html">Science Fair Coach's step-by-step guide</a>, you can make sure your science fair board stands out and impresses at the science fair!</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><hr style="clear:both; border-style:dotted" data-marker="clearFloat"><h3>Where can I find a science fair competition?</h3><p><img src="/images2/flex/179_Intro Science Fair Projects 32.png" data-size="100" data-float="left" style="width:100px; float:left">Science fair competitions are an excellent opportunity to explore science. One of the of the premier science advocacy organizations, the Society for Science, is associated with more than 400 science fair competitions in almost every US state, as well as over 70 other countries, regions, and territories. You can find out if there's a <a href="https://findafair.societyforscience.org/">Society of Science affiliated science fair</a> near you!</p><p>The <a href="http://physics.usc.edu/~gould/ScienceFairs/">The www Virtual Library: Science Fairs website</a> also has a collection of science fairs from all over the world, as well as national, state, regional, local, and virtual competitions!</p><hr style="clear:both; border-style:dotted" data-marker="clearFloat">

Medicine and health are about understanding how our bodies work and how we can keep healthy. Doctors identify and treat diseases, and commonly-occurring discomforts such as allergies and skin issues. Nutrition plays a crucial role in maintaining good health.

All Science Fair Projects

1000 Science Fair Projects with Complete Instructions

SPF Ratings vs. Sunblock Thickness

Hypothesis

Method & Materials

Results

Why do this project?

Also Consider

Full project details

Related video

Related Science Fair Project Ideas