# Lie-to-children

A lie-to-children is an expression that describes a form of simplification of material, for consumption by children. It is itself a simplification of certain concepts in philosophy of science.

Because life and its aspects can extremely difficult to understand without experience, to present a full level of complexity to a student or child all at once can be overwhelming. Hence elementary explanations, especially a child, tend to be simple, concise, or simply "wrong" — but in a way that attempts to make the lesson more understandable. (Sometimes the lesson can qualified, for example by claiming "this isn't technically true, but it's easier to understand.") In retrospect the first explanation may be easy to understand for its inaccuracies, but it will be replaced or a more sophisticated explanation which is closer to "the truth." This "tender introduction" concept is an important aspect of education.

Such statements are not usually intended as deceptions, and may, in fact, be true to a first approximation or within certain contexts. For example Newtonian mechanics by modern standards, is factually incorrect (as it fails to take into account relativity or quantum mechanics) but it is still a valuable and useful model in certain stituations. One particular progression of "lies" or simplifications, each of which are debunked or unraveled as one progresses deeper into a subject (in this case, physics), runs as follows (from h2g2 (http://www.bbc.co.uk/dna/h2g2/A685055)):

1. Weight is constant.
• Children in primary school learn that the weight of something doesn't change if you just change its shape.
2. Weight is not a constant. What's actually constant is mass.
• In secondary school, teenagers often learn that on the moon or on Mars, an objects' weight will be different, because gravity in those places is different, but the mass will stay the same.
3. Mass is not a constant, but depends on the velocity of the object, relative to the speed of light, which is a constant.
• Later on, college students find out that relativity says that the mass of an object can vary depending on velocity.
4. The speed of light is not, in fact, a constant, but may have been larger than its current value during the early life of the universe.
• This is a hypothesis that is likely, but may or may not be true. People finally realize this level around the time they're in their mid 20's and maybe doing their Ph.D. (And some people don't ever get to this level at all.)

The term appeared in the book The Science of Discworld, co-authored and party based on ideas created by Terry Pratchett, and in Collapse in Chaos and Figments of Reality, both by the other two co-authors of The Science of Discworld, Ian Stewart and Jack Cohen.

• The Science of Discworld (http://www.funny.co.uk/comedy/prod_152-0091886570-The-Science-of-Discworld.html)
• h2g2 (http://www.bbc.co.uk/dna/h2g2/A685055#back3)

• Art and Cultures
• Countries of the World (http://www.academickids.com/encyclopedia/index.php/Countries)
• Space and Astronomy