Soap is a type of cleaning agent that has been used for centuries. It is made through a process called saponification, which involves reacting fats or oils with an alkali, such as sodium hydroxide (for solid soap) or potassium hydroxide (for liquid soap). This reaction produces soap molecules, which consist of a hydrophilic (water-loving) head and a hydrophobic (water-repelling) tail. Soap molecules are effective at removing dirt, oil, and grease because the hydrophobic tails attach to the dirt and grease particles, while the hydrophilic heads allow them to be rinsed away with water.

Detergents, on the other hand, are synthetic cleaning agents that were developed in the early 20th century. Unlike soap, detergents are typically made from petroleum-based chemicals. Detergent molecules have a similar structure to soap, with a hydrophilic head and a hydrophobic tail. However, the composition of detergent molecules can be varied to suit specific cleaning needs. Detergents are generally more effective at removing stains and dirt in different water conditions (hard water, for example) compared to soap. They are also known for their foaming and emulsifying properties.