Thread: Curtains half closed - siblings arguement

Hey I have an odd question and would be very thankful of someone could answer it.
I like to leave the curtains opfen in order to get woken up by the sun light in the morning. However my sister wants them closed. My issue is that with the curtains being closed, i do not wake up in the morning and i am way more tired. I need light to wake up. Therefore i wanted to leave one of the curtains closed and the other one open as a compromise. However she says this is not fair, as light bents. I get what she means. However my site of the room would still be more than half as much darker, as when both curtains where open, wouldnt it? Sorry it is a very weid question, but i wanna know if this is a fair solution. How does half the amount of light get in the room? Thank you very much in advance!

Originally Posted by salma2004

Hey I have an odd question and would be very thankful of someone could answer it.
I like to leave the curtains opfen in order to get woken up by the sun light in the morning. However my sister wants them closed. My issue is that with the curtains being closed, i do not wake up in the morning and i am way more tired. I need light to wake up. Therefore i wanted to leave one of the curtains closed and the other one open as a compromise. However she says this is not fair, as light bents. I get what she means. However my site of the room would still be more than half as much darker, as when both curtains where open, wouldnt it? Sorry it is a very weid question, but i wanna know if this is a fair solution. How does half the amount of light get in the room? Thank you very much in advance!

Actually this is as much biology as physics, I think. The problem is that our eyes adjust their sensitivity to light according to how much there is. If you draw back only one curtain out of two, you are indeed only letting half the intensity of light into the room, from the point of view of the physics of it. But it won't feel like that, because the eye simply turns up its sensitivity, which largely, though not entirely, compensates. It's the same with hearing: the ear has variable sensitivity, which is why for sound we use a logarithmic scale (decibels) instead of a linear scale, to measure the perceived intensity of sound. I don't know whether an equivalent logarithmic scale for perceived light intensity exists, but I would not be surprised.

I suggest to get what seems like half the light into the room you should draw back the curtain enough to uncover only 10% of the area of the two windows. If a logarithmic relationship applies, this should feel like half the brightness. Why not try it and let us know how you get on?

As for the light "bending", I think it will be more due to the fact that light can enter diagonally from either side of the window as well as directly, so the illuminated area will be a spreading wedge shape. And also of course when it hits the walls of your bedroom, some of it is reflected from there into other parts of the room, brightening all of it to some degree.