When the solid has a high affinity for water - in which case it is called hydrophilic (high energy e.g. glass)- water spreads. In the opposite case of hydrophobic (low energy e.g. teflon) surfaces, water does not spread but, instead, forms at equilibrium a spherical cap resting on the substrate with a 'contact angle'.
Infections such as trichomoniasis, gonorrhea, and Chlamydia (all STDs); and yeast infection can all cause vaginal discharge. Vaginal discharge can be associated with other symptoms such as burning or itching. Antibiotics are given for infections that cause vaginal discharge.
More info on Throat Gonorrhea. All of us are familiar with Gonorrhea. It is an STD. It causes a thick yellow discharge and pain passing urine in both men and women. The symptoms can come on anytime between 3 to 30 days of exposure although 10% of people infected with Gonorrhoea will not show any symptoms.