system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do I need more dish-washing liquid for greasy plastic kitchenware than for metal/glass/ceramic?

Does the plastic make the dish-washing liquid less effective? Does grease stick better to plastic? Or does the plastic just feel more "greasy" for some reason?
gpt
Plastic is like grease - it's hydrophobic, so grease sticks to plastic like grease sticks to grease.  Detergents are amphipathic, ie they have a part that likes water, and a part that likes grease.  So, the part that likes grease sticks to the grease, and the part that likes water pulls the whole thing into the water.  In order for grease to come off the plastic, there must be enough detergent to convince it to come loose.  Metal and glass are hydrophilic.  They like water, but don't particularly care about grease.   So it's easier for the detergent to get to the grease and solubilize it.