What's the sun made of, dad? It feels hot.
A seemingly simple quesion from my four year old daughter.

Now, I'm an engineer and I'm used to speaking to people all day in a highly concentrated acronym-laden convoluted mess of words and technobabble. So my first thought was to answer -

ah, subatomic fusion of hydrogen nuclei to form helium in a 14 million degree plasma.

Oh. 4 year old. Have to explain fusion.
To explain fusion, have to explain chemical elements.
To explain chemical elements, have to go into subatomic physics.
To explain subatomic physics, have to go into mass/energy equations.
To explain mass/energy conversion, have to engage in laws of physics revolving about mass, pressure,nucleus repulsion and the speed of light.

THEN-To explain how we know all of this, have to refer to the thermonuclear weapons program.
To explain that, have to go into mechanics of isotope separation and enrichment within a centrifuge / neutron cannon environment.
To explain that, have to explain global geopolitical history of the early 20th century.
To explain all of that, have to go into politics, fascism and communisim.
To explain how that could be executed, have to go into tactical military planning, bomber fleets, ICBMs, terrorism and the struggle against the axis evil powers.

And then we have to take into acount why the sun is a (mainly) uniform sphere 93,000,000 miles away. So have to explain gravity, simple harmonic motion, gas density etc.

To explain why it feels hot , have to explain radiation. To explain that, have to explain the theory of electromagnetic wavelengths. To explain that, have to involve use of mathematics to determine frequency versus EM band. And also briging the speed of light, vacuum permeability and electromagnetic wave propagation, wave-versus-particle photon theory as disseminated by quantum mechanics versus Einsteins' general relativity. And then it feels hot because of absorbtion, nerve receptors, chemical nerve conduction, axon interlinkage, cogniscence and resoning.


So either I can say "you'll find out when your older" (like, 14 years later in total) or I can avoid the TMI and say..

'Fire'

at which point she replied, in a disgusted tone of voice "Fire? FIRE!!?? DOH!"

To this day I don't know why the answer gave so much dissatisfaction... maybe she'd bet on the outcome with a schoolmate and realised she had wrongly said 'Fusion plasma brought about by the subatomic combination of hydrogen nuclei into helium and mass-to-energy conversion".
( Rotating Wobbly Hat That's not a banana. THIS is a banana., Thu 6 Sep 2007, 16:55, Reply)