To Amy(IA-20250605).docx

Background of chemical principles：

“Principle of similarity and compatibility": Fat-soluble cosmetics are more easily dissolved by non-polar solvents.

The polarity of different vegetable oils and mineral oils is different (the polarity of olive oil is slightly higher than that of mineral oil).

Molecular structurewithIntermolecular forceDetermine the ability to dissolve.

Emulsifiers (such as Polysorbate 80) can help mix makeup remover oil with water for easy cleaning.

Independent variable：

The main types of oils used in the makeup remover formula (oils of different polarities)
For example：

A: 100% mineral oil (non-polar)

B: 100% olive oil (slightly sweetened)

C: Mixed oil (50% mineral oil + 50% olive oil)

Dependent variable：

Cleaning efficiency (use a colorimeter to measure pigment residues or image analysis)

Control variable：

Control variable	Control method
Types and quantities of cosmetics used	The same brand/the same waterproof eyeliner, apply the same area
Makeup remover oil usage	1.0 mL each time you use it, take it in precise quantities
Makeup remover time	Scrub for 30 seconds each time
Cleaning method	Standardized use a cotton swab to remove, scrub with the same pressure
Experimental temperature	The control is carried out at room temperature (22-25°C)
Emulsifier concentration	Add the same mass fraction to each group (such as Polysorbate 80 of 10%w/w)

Materials and equipment：

Olive oil, mineral oil

Polysorbate 80（Tween 80，乳化剂）

Waterproof eyeliner or lipstick (fat-soluble cosmetics)

Glass slides or plastic sheets (simulating "skin”)

Glass rod, measuring cylinder, straw, stirring rod

Cotton swabs

Colorimeter (if any) or high-resolution mobile phone camera + image analysis software (ImageJ)

Balance, thermometer

Brief description of experimental steps：

Waterproof on glass sheetsApply a piece of eyelinerapproximately1 cm²The pattern of the area.

Let stand for 5 minutes to "attach”.

Add 1 mL of three different formulas of makeup remover oil drop by drop, stir well to emulsify (use 10% Polysorbate 80).

Rub evenly with a cotton swab for 30 seconds.

Take photos of residual cosmetics and save them; or measure the color absorbance after extraction with alcohol.

Repeat the above steps three times for each group.

Data collection and processing methods：

Method 1: Colorimeter / photometer method (quantitative)

useIsopropanolExtract residual cosmetics → colorimetricdish →The colorimetric meter measures absorbance.

The worse the cleaning, the higher the absorbance.

Method 2: Image analysis method (quantitative)

Take an image of the glass sheet before and after makeup remover.

Use ImageJ software to measure the color area/average gray value.

Use relative residual rate = (residual color area /original color area) ×100%

Data presentation recommendations：

useHistogramShow the cleaning efficiency of different oil formulas (residual content%)

Comparison of drawings, sample photos before and after makeup remover

Analyze the trend: is polar oil or mixed oil more effective?