Second Blog Submission

Aim
To determine whether there is a difference in the protection against UV rays by sunscreens of different SPFs 15+, 30+ and 40+.

Hypothesis
There won't be a significant difference with the protection given by sunscreens with higher SPF to those with lower.

Equipment
-3 sunscreens of the same brand but different SPFs
-1 timer
-9 pieces of photo paper
-9 clear plastic folders
-1 bottle of photogenic fixer (sodium thiosfulate)
-1 A4 sized plastic rectangular container
-1 knife
-1 working computer and scanner

Risk Assessment...


Method
1. Cut the photo paper vertically into 3 equal sheets of paper and label the sunprint paper from 1 to 3 to indicate the SPFs
2. Squeeze a small amount (size of a 50 cent coin) of sunscreen with SPF 15+ on the centre of the glossy side of the phot paper and spread the sunscreen equally around the paper
3. Repeat steps 1-2 with SPF 15+ and 45+ on the remaining 2 sunprint paper
4. Place the 3 sheets of paper carefully into the plastic folders and leave it outside in a sunny area
5. Start the timer for 5 minutes
6. Place 200mls of Photogenic fixer into the Rectangular container in a dimly lit room
7. Bring the folder back into after 5 minutes
8. Place the photo paper glossy side down for 3 seconds in the photogenic fixer and then rinse immediately with cold water
9. Lay it to dry for fifteen minutes
10. Scan the three solutions onto the computer
11. Analyse each one by determining the blue pixel value to get an average darkness for each sunscreen and time interval and compare the data
12. Repeat steps 1-16 twice leaving the folder outside for 10 minutes the first repeat, and 20 minutes for the second repeat


This experiment will be repeated once again to ensure it's reliability
This is a very rough example of how the table may look like...

WHoops! photo turned out ridiculously small! {click} to enlarge it