Warum?

A dialogue with Sarah, aged 3: In which it is shown that if your dad is a chemistry professor, asking "why" can be dangerous (via Nerdcore)

DAD: Why do I use soap?
SARAH: Yes.
DAD: Because the soap grabs the dirt and lets the water wash it off.
SARAH: Why?
DAD: Why does the soap grab the dirt?
SARAH: Yes.
DAD: Because soap is a surfactant.
SARAH: Why?
DAD: Why is soap a surfactant?
SARAH: Yes.
DAD: That is an EXCELLENT question. Soap is a surfactant because it forms water-soluble micelles that trap the otherwise insoluble dirt and oil particles.
SARAH: Why?
DAD: Why does soap form micelles?
SARAH: Yes.
DAD: Soap molecules are long chains with a polar, hydrophilic head and a non-polar, hydrophobic tail. Can you say ‘hydrophilic’?
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