cleanlogicshortIt regulates our daily movements, but it feels no interest in our lives. It directs us when to come and go, but does not care if we pay attention. What is it?
A clock.
Similar riddles
See also best riddles or new riddles.
cleanlogicshortThis old one runs forever, but never moves at all. He has not lungs nor throat, but still a mighty roaring call. What is it?
A waterfall.
cleanlogicshortWhat is as light as a feather but impossible to hold for several minutes?
Your breath.
cleanlogicwhat am II’m teary-eyed but never cry,
silver-tongued, but never lie.
double-winged, but never fly,
air-cooled, but never dry.
What am I?
Mercury. The element looks shiny, silver, and is wet. The god Mercury has two wings but only uses them to run.
cleanfunnyshortWhat did the beach say when the tide came in?
Long time no sea.
cleanshortI look flat, but I am deep,
Hidden realms I shelter.
Lives I take, but food I offer.
At times I am beautiful.
I can be calm, angry and turbulent.
I have no heart, but offer pleasure as well as death.
No man can own me, yet I encompass what all men must have.
Ocean.
cleanfunnyshortWhat do sea monsters eat?
Fish and ships.
animalcleanfunnyshortHow do birds communicate?
On twitter.
cleanlogicYou have two lengths of rope. Each rope has the property that if you light it on fire at one end, it will take exactly 60 minutes to burn to the other end. Note that the ropes will not burn at a consistent speed the entire time (for example, it's possible that the first 90% of a rope will burn in 1 minute, and the last 10% will take the additional 59 minutes to burn).
Given these two ropes and a matchbook, can you find a way to measure out exactly 45 minutes?
The key observation here is that if you light a rope from both ends at the same time, it will burn in 1/2 the time it would have burned in if you had lit it on just one end.
Using this insight, you would light both ends of one rope, and one end of the other rope, all at the same time. The rope you lit at both ends will finish burning in 30 minutes. Once this happens, light the second end of the second rope. It will burn for another 15 minutes (since it would have burned for 30 more minutes without lighting the second end), completing the 45 minutes.
cleanshortUntil I am measured I am not known. Yet how you miss me when I have flown.
Time.
cleanpoemsshortAlive without breath,
As cold as death;
Never thirsty, ever drinking,
All in mail never clinking.
Fish.
