Science
Exploring "Why" questions about Science
484 articles
Why do engines have a harder time starting when they are cold?
Fuel sprayed into a cold engine doesn't stay in vapour form as well as a warm engine. Much of the fuel condenses on the cylinder walls similar to a cold glass of water on a hot day. So you need more f
Why is it that 60° in air feels fine but when you get in a 60° swimming pool it feels cold and comfortable?
The reason why 60 degree air is so much more comfortable than 60 degree water is that water is about 25 times as thermally conductive as air is. This means that water at any temperature transmits its
Why is it so difficult for Iran to build nuclear weapons today, if the US could build them in the 40’s?
[The Manhattan Project](_URL_2_) was a tremendous project. It [ grew to employ more than 130,000 people and cost nearly US$2 billion (about $26 billion in 2015[1] dollars). Over 90% of the cost was fo
why did the fur on our bodies dissapear if some humans moved to colder climates?
The fur on our bodies was gone forever. Then we went north. We killed animals and stole their fur.
Why does is it impossible to find news that is accurate and can be trusted?
If you like podcasts, try listening to On The Media. They examine and explain news coverage of all kinds. The hosts don't report the news per se, but rather help listeners to understand the often conf
Why do people tend to feel cold when they are depressed?
I've never heard this. Do you have any source that this is even a thing? My guess is that malnourishment and/or inactivity causes poor circulation and general lethargy, which might feel like depressio
Why do moths like light so much??
they don't. The leading theory is that moths use moonlight to navigate. The moon, being so far away, maintains a relatively fixed position in the sky from the standpoint of a moth.
Why is air generally colder in the upper atmosphere, even though hot air rises, and it receives more direct sunlight?
Air pressure is equal to the weight of all the air above in the atmosphere, so it decreases with altitude. Therefore when hot air rises, its pressure decreases and it expands and gets colder. The reas
Why does using electronics with a lit up screen before bed make it harder to fall asleep?
One of the reasons we get tired and fall asleep is because of [Melatonin](_URL_0_). Melatonin is a hormone found in almost all biological life. Now let's make this easy to understand.
why do some people “run hot” or “run cold”?
AFAIK your thyroid settles this. I also seem to be hot a lot and feel uncomfortable in situations where other people are just fine. I've asked my dermatologist why is that and she asked if anyone in m