Why do you place the cover slip on a 45 degree angle?

Placing the cover slip at a 45-degree angle helps to minimize the formation of air bubbles when it is lowered onto the specimen. This technique allows the liquid sample to spread evenly beneath the cover slip, ensuring a more uniform thickness and better optical clarity for viewing under a microscope. Additionally, it facilitates the proper sealing of the slide, which can help prevent contamination and evaporation of the specimen.