I was taught in my Physics lessons that the hotter an object is, the quicker it looses heat. My plumber reckons that it's cheaper to keep the hot water on all day rather than heat it and let it cool if it's not used. What's the better way? Keep the water hot, or let it cool, and then heat it on demand?  

when cold the milk poured with a neat stream whereas after microwaving it sloshed all down the side of the jug.

An age old debate between my grandfather and my mother.

He insists on hot days to close the house up and pull all the blinds down.

My mother however opens all the blinds and every window to let air through.

Who is right? I know there are many factors but surely one must be generally cooler than the other.

If it helps we live in a humid Queensland climate, would it make any difference if it was a dry hot environment?

If we consider thermodynamics and its law that heat travels from hot to cold, I was curious as to how or what occurs when sunlight is travelling to Earth. The gap between the Sun and the Earth is effectively a vacuum and also the low pressure at high altitudes mean that it is very cold, surely the heat should be dispersed by then and not reach sea level.

I would like to know how we still manage to feel the heat.

Thank you

For example I am wondering, in the following thought experiment: If you have a single atom resting in a vacum and it is hit by a photon, causing it to heat, what is the reason for the resulting motion of the atom? i.e. what intrinsic changes occour in a single atom when heat is applied.

Curtains are traditionally made about 50% wider than the window opening, so they are thrown into folds or pleats. My friend says this is necessary to obtain optimum heat insulation. I say that the folds will just provide more surface area for air and heat to pass through. Who is right? What is the optimum configuration for a set of curtains?

I get migraines that are located in that brain hemisphere and I wondered if there was any connection between this, emotion and also cell phone creating the same effect, if held up against the side of the head long enough.