How to Calculate Effectiveness of a Sunscreen

Ultra Violet radiation is a part of the electromagnetic spectrum that comes from the sun. This type of radiation is not well suited to the human skin. With constant sun exposure along with the other environmental and external factors, our skin gets damaged and becomes parched. You will notice that the appearance of signs aging along with experiencing problems due to hyper-pigmentation. So as to get rid of hyper-pigmentation refer an Ambi fade cream review. In fact, it has been linked to causing cancers in some cases. However, this radiation is not visible to human eyes. There are some different types of ultraviolet radiation. The ozone layer above the earth helps to block out most of it. However, some of it does still get through and penetrates human skin. Besides cancer, this UV radiation is known to cause sunburns. You should apply sunscreen so as to avoid it.

Aside from protecting your skin from darkening, sunblock can also help prevent sunburns. Apply your favorite sunscreen on every possible part of your body, both covered and uncovered, to minimize exposure to harmful UV rays.

What you should know about sunscreen is that a higher SPF does not necessarily mean longer protection. Here are some things that you should look for in a good sunblock or sunscreen:


How to Measure the Effectiveness of a Sunscreen

Different brands exist that are used to protect against UV radiation. However, all of them are rated differently. It is important to find out if they are delivering what they claim. The simplest way to determine this is using the UV index. The UV index can be summarized as illustrated below:

Below 3Moderate
7-9Very High
9 and AboveExtremely High


  • Six sheets of glasses that are about 50 centimeters by 50 centimeters. You can purchase them from the local hardware store.
  • Five brands of popular sunscreens of SPF 15, 30 and 50 respectively.
  • A UV meter; you can buy one on Amazon.
  • Five pairs of disposable gloves
  • A bottle of glass cleaner and a piece of cloth
  • A wooden box with no covering at the top

What to Do 

The independent variable is taken to the sunscreen brand with its SPF rating. The UV index is the dependent variable here. The controls are the time at which the experiment takes place and the location in the world where this investigation takes place.

You should put the sunscreens in their respective groups accordingly. Proceed to label each of the brands as A, B, C, D, and E. Use the glass cleaner to clean the six glass sheets. Label the five glass sheets as A, B, C, D, and E and indicate the respective SPF rating of these sheets. Label the sixth sheet “None” and use it as a control.

Apply Sunscreen onto the sheets of glass according to the tag you gave them. Ensure that you use similar quantities of sunscreen on each sheet. Do not use too much sunscreen. Use gloves when applying sunscreen and make sure that you change gloves during each application.

Place the box in the direct sunlight without any shadows present. Put the UV meter inside the UV box and measure the UV index. Use the sheet labeled “None” to cover the wooden box. Use the UV meter to measure the UV index in the box. Be careful when dealing with glass.

Now repeat the reading for all the other sheets of glass and record the index. Record your findings in a table as below.

Brand of sunscreenUV index
Without GlassWithout SunscreenSPF 15SPF 30SPF 50


You cannot possibly be well and healthy without sunshine. Trouble is, you can easily get too much UV too soon. That said, you need to choose when you should catch your sunshine — early mornings and late afternoons are ideal — and make sure never to stay basking around for more than 15 minutes. Getting yourself a sunscreen that matches your daily activities and sun protections needs is also a premium requirement. Use other means to physically block out the sun, including umbrella, sunglasses, and a broad-brimmed hat.

After the experiment, you will notice that UV index was significantly different for products with different SPF rating. The difference was especially pronounced for products with SPF rating of 15 and 30. However, there was no significant difference in products with SPF rating between 30 and 50.

Cover photo: weheartit

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