What is the chemical or liquid that added to give sunscreen spf factor?

The chemical compounds that are primarily responsible for providing sun protection factor (SPF) in sunscreens are called UV filters. These UV filters work by absorbing or reflecting ultraviolet radiation from the sun, thereby reducing the amount of UV radiation that reaches the skin.

There are two main types of UV filters:

* Chemical UV filters: These filters work by absorbing UV radiation. They convert UV energy into heat, which is then dissipated by the skin. Chemical UV filters include oxybenzone, avobenzone, octisalate, octocrylene, and homosalate.

* Physical UV filters: These filters work by reflecting UV radiation. They scatter UV rays away from the skin. Physical UV filters include zinc oxide and titanium dioxide.

The SPF factor of a sunscreen indicates the level of protection it provides against sunburn. The higher the SPF, the greater the protection. A sunscreen with an SPF of 15 blocks about 93% of UVB radiation, while an SPF of 30 blocks about 97% of UVB radiation.

Sunscreens also typically contain other ingredients, such as moisturizers, antioxidants, and fragrances. These ingredients can help to improve the skin's appearance and protect it from damage.