What happens to light (and sound)?

[G-CPTN]

Every night I visit the bathroom (several times).

I switch on the light (which 'floods' the bathroom), then switch it off.

Where does it go to?

Does it escape through the adjoining room?

Does it join up with dark matter (that we are lead to believe exists in abundance around us)?

I think we should be told.

[llondel]

It all gets absorbed into the surrounding walls, and ultimately ends up as heat. Every time you switch on the light, you are hastening the heat death of the universe.

[G-CPTN]

That seems plausible, as I have just had to open the bedroom window as I was 'overheating'.

[PHXPhlyer]

Cover the walls, floor, and ceiling with mirrors.
That should hold the light in until you open the door.

PP

[Boac]

On reflection, that should work.

[G~Man]

Put a flashlight in the room with the back cover off----that will capture it and you can use it later as needed. You just need batteries to stop the unit from imploding while holding all that energy. They work great--I have several.

[Fox3WheresMyBanana]

..and remember to switch the flashlight on before picking it up.
That way, it's lighter, as there are more lift bernoullis around.

[bob2s]

.and remember to switch the flashlight on before picking it up.
That would not work as I believe that flashlights are only used for carrying around dead batteries, hence no light when switched on.

[Fox3WheresMyBanana]

Good point, well made.
As ever with scientists, I provided information which was theoretically correct but of no practical use.

[OneHungLow]

It all gets absorbed into the surrounding walls, and ultimately ends up as heat. Every time you switch on the light, you are hastening the heat death of the universe.

Ah one of Kirchhoff's perfect black bodies!

A Vantablack moment...



Seems I am behind the times...



Probably still not as black as Adrian Mole's Noddy wallpaper after he painted it black, and still failed to hide Noddy's ubiquitous face.

[OneHungLow]

I thoroughly enjoyed this potted history of the science of light. I share it here.

[OFSO]

Since Mrs OFSO and her new Knee moved into the guest bedroom (she's now back with me) and the new LED street lights are not bright enough to illuminate the way to the WC, I bought two more solar lights, but portable, which I charge up on the terrace all day but bring into the passage at night. In answer to the OP, therefore, a miniscule number of the sun's photons are captured and stored each day and released overnight indoors. Some disappear down the WC but the majority bounce off the light walls and fall onto the carpet, which is dark, raising the temperature.

[OFSO]

Further question: one can reflect light many times between two or more mirrors. Is there a limit to this ?

[Boac]

On reflection (sorry...) there has to be, since energy will be lost at each reflection as the light passes through the surface of the mirror.

[tango15]

I'm completely in the dark with this...

What you need is a neighbour opposite who has a powerful light on the path which illuminates every time one of their five cats goes for a stroll. The light then reflects through the frosted glass in the bathroom sufficiently for one to be able to aim as accurately as possible, and since I live alone, I don't have to worry about leaving the seat up!

[jimtherev]

I'm completely in the dark with this...

What you need is a neighbour opposite who has a powerful light on the path which illuminates every time one of their five cats goes for a stroll. The light then reflects through the frosted glass in the bathroom sufficiently for one to be able to aim as accurately as possible, and since I live alone, I don't have to worry about leaving the seat up!

I don't have an obliging neighbour; instead #1 son and I have a tradition of exchanging wacky and usually useless Christmas presents. However, the 2021 present met with approval, and we're still pleased by the welcoming light in the bathroom whenever it's approached.

Light.jpg (23.67 KiB) Viewed 746 times

[Fox3WheresMyBanana]

since energy will be lost at each reflection as the light passes through the surface of the mirror.

This is the reason astronomical mirrors are put on the front face of the glass, not the back.

It does make cleaning a specialist operation.

[Boac]

the welcoming light in the bathroom whenever it's approached.

As it is 'motion-activated, Jim, do you need a torch if you just go for a pee?

[G-CPTN]

Just wave it from side to side.