Wednesday, May 6, 2020
Spectroscopic Analysis of a Sunscreen Product free essay sample
In this lab, our concept is to find the extinction coefficient â€Å"? †for a specific sunscreen with a sun protection factor (SPF), we are using brand: NO-AD SPF 15 for this experiment, our extension coefficient â€Å"? †value is to be 482. 04 cm2/g. Objective: Our objective with this experiment is to find the relation of sun block with the extension coefficient by measuring the absorbent rate of UV rays the sunscreen can absorb. And how it can absorb harmful waves that emit from the sun. Ultra Violet (UV) rays are harmful for the skin if person stays for too long in the sun. It can cause damage to the skin and may lead to cancer. Also, to relate other sunscreens products to another, as band name price and how well do they do once exposed to the suns UV rays. Theory: As Beer’s Law indicates: A= (? ) (l) (C) Where is A is the Absorbance, is proportional to C, the concentration of solution, the higher the concentration the higher the absorbent. We will write a custom essay sample on Spectroscopic Analysis of a Sunscreen Product or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page ‘A†is also proportional to (l), the length of tube used, the longer the tube, the more molecules in the solution can absorb rays , as they are subjected to more rays. The absorption rate increased for the concentrated solutions and gradually decreased from tube 1 to tube 6, that means the more particles where intercepting the path of UV rays in the most concentrated solution (tube 1)where A=0. 24, and in tube 6(most diluted) the absorption rate was 0. 056 And in our wavelength vs. absorbent plot, we see that most of the absorbency occurred when the wave length is around 290nm and 300 nm That means the concentrated solution with sunscreen absorbed most of the UV rays and energy, therefore blocking it from passing through. Question UVA, UVB, UVC are all in the family of Ultra Violet Rays, which are electromagnetic radiation with wavelength shorter than a visible light, because the spectrum starts at a wavelength shorter than wavelength we identify as color. UVA, UVB, UVC are each with a different wavelength. Type of UVWavelength UVA , long wave, also called black light400nm – 320 nm UVB , medium wave320nm – 280 nm UVC , shortwaveBelow 280nm According to SPF given, it looks like they are consistent, as most of the absorbency happen around 300nm- 320nm (UVB, Medium Wave), but all with different rate of absorption, TypeMax absorbency Coppertone 300. 25 Kroger kids 450. 48 NO-AD 450. 60 Coppertone 150. 65 NO-AD 150. 43 And according to other groups results and ours in calculating the extinction coefficient (? ), the higher the SPF the higher the (? ) as shown SPF? Value 15880 301159. 4 15482. 04 301146 And yes we did expect a relationship between ? and SPF, as per Beer’s Law A= (? ) (l) (C), and relationship is proportional (A ? ?), the higher ? , the higher the SPF the more absorbency occurs for UV rays.
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