2013-11-26
Explanation
The Joke
A man says to his wife, "I feel like we're neglecting little Billy." The woman replies, "It's okay. He's small." In the background, a sad-looking small child (Billy) peers around a corner. The caption reads: "Physicists make terrible parents."
The Humor
The joke hinges on a physics pun. In everyday language, "neglecting" something small means failing to give it adequate attention or care. But in physics, "neglecting" small quantities is a standard and perfectly acceptable practice -- when solving equations, physicists routinely ignore (neglect) terms that are sufficiently small because they have negligible impact on the result. The mother is applying this physics convention to parenting: since Billy is small, it is acceptable to neglect him. The sad child in the background makes the joke land harder by showing that this approach does not work as well with children as it does with equations. The caption explicitly frames the joke as a consequence of thinking like a physicist in everyday life.
References
In physics and mathematics, it is common practice to "neglect" small terms in equations -- for example, ignoring air resistance, friction, or higher-order terms in a Taylor expansion when they are sufficiently small compared to the dominant terms. This simplification technique is fundamental to problem-solving in physics.