SCIENCE TOPIC - Ask here what you don't know!

[CooperO 7,956]

What is viscosity?

 

How do you change the viscosity?

 

Viscosity is something like the thickness of a fluid or gas. It determines how easy it spreads. Compare water and honey. When you throw a glass of water on the floor, the pool gets a lot bigger than when you throw the same amount of honey on the floor. This means that the viscosity of honey is higher than the viscosity of water. You can change viscosity by changing the temperature: boiling water has a lower viscosity than water from the fridge. There might be some exceptions and other ways to change viscosity but I don't know that at the moment.

[LiquidGold 1,370]

What is viscosity?

 

How do you change the viscosity?

viscosity is how thick or dence something is typically a fluid, some are very liquid fluids such as water, to change it add some thing like flour. There are other very thick and viscous fluids like Glass it is actually a fluid not a solid, and to change its viscosity you would heat it ( if you look at very old glass windows they are always thicker at the bottom than the top because glass moves very very slowly and is acted upon by gravity over decades i hope that helps a little

there are also other types of viscosity there is something called a non newtonian dilatant fluid if you make a very thick custard by using loads of corn starch to thicken it it is still runny and acts like a fluid if you made enough of this thick custard and filled a swimming pool with it it has a strange property that if you were to run very fast over it you would not sink, the harder your feet hit the custard the more force it " hits you back" and therefore supports your weight and you could run the full length of the pool and not sink to the bottom, the moment you stopped running you would swim with the fishes

Edited November 14, 2012 by LiquidGold

[CooperO 7,956]

The glass example is great LiquidGold! Not many people know that.

[LiquidGold 1,370]

1. I drop a 5kg & 10kg ball at the same time , which ball drops faster

2. I am on a train travelling at 50km per hour and throw a ball in forward direction and one backward , what are the speeds of the balls

answer to no1 they both fall at the same rate as gravity acts upon the masses to the same degree, they would only fall at different rates if gravity was different. If you dropped the 5 kg mass on earth it would drop at its normal rate, if you then dropped the 10kg mass on the moon it would fall 6 times slower as gravity on the moon is 1/6th of that on earth

answer no2 assuming you throw both balls with the same force, gravity and head wind do not take any part in the equation there is no differance to the speed they will travel. if you were to observe the balls the moment they were thrown it may appear one is moving faster then the other one due to a phenominon called paralax. this is similar to when you look out the window of a car you are traveling in, objects further away appear to go by slower then something closer to you

[CooperO 7,956]

Anyone knows the answer to this one? (I know the answer, but I don't get it)

 

Someone looks horizontally through a window, 20 meters above the ground and sees an object falling down vertically. Four seconds later the object touches the ground.

At which speed passed the object by the window?

 

Physics isn't my strong suit.. :unsure:

Edited November 14, 2012 by CooperO

[LiquidGold 1,370]

the object is decending at 5 meters per second

take the hight 20 then divide it by the time it took to fall this is 4 20/4 = 5 the ratio is given in meters per second so 5 mps

distance / time = speed ratio

[LiquidGold 1,370]

Why do we excist?

the answer to life the universe and everything is quoted from "the hitch hikers guide to the universe" by Douglas Adams and is of course 42

[Guest]

the answer to life the universe and everything is quoted from "the hitch hikers guide to the universe" by Douglas Adams and is of course 42

Actually, if you refer to my reply, it was not quoted from everywhere :P

That's how I re-elaborated what I studied to give a reply :)

[CooperO 7,956]

the object is decending at 5 meters per second

take the hight 20 then divide it by the time it took to fall this is 4 20/4 = 5 the ratio is given in meters per second so 5 mps

distance / time = speed ratio

See! That's what I thought but the correct answer is supposed to be 15m/s.

But if you think about it logically, that answer is impossible, even if you leave out acceleration. Horizontally you get 60 meters in 4 seconds at that speed, with acceleration of 9.81 m/s^2 it will even be more.

They used this formula to get to that asnwer: x=x0 + v0t+ 0.5at^2 x = distance, v = velocity, t = time and a = acceleration.

[splitterpoint 10,986]

why does smoking affects your voice?

Edited November 14, 2012 by splitterpoint

[mrandrewstevens 1]

Smoking damages tissues in your vocal chords, resulting in changes to your voice.

[chiyaProgramer 1]

See! That's what I thought but the correct answer is supposed to be 15m/s.

But if you think about it logically, that answer is impossible, even if you leave out acceleration. Horizontally you get 60 meters in 4 seconds at that speed, with acceleration of 9.81 m/s^2 it will even be more.

They used this formula to get to that asnwer: x=x0 + v0t+ 0.5at^2 x = distance, v = velocity, t = time and a = acceleration.

 

now what does that mean ? :huh: :huh: :D :blink: :blink: :blink:

Edited November 15, 2012 by chiyaProgramer

[CooperO 7,956]

It means I'm terrible at physics, because I failed that exam around 8 times. :wacko:

[niknik655 2]

This topic is best one ive seen this month in off-topic discussion.

[skitee 555]

This topic is best one ive seen this month in off-topic discussion.

 

Except that the majority of it is philosophy, not science. :unsure:

[niknik655 2]

Hehe, true.

[Guest]

Except that the majority of it is philosophy, not science. :unsure:

I don't see philosophy, honestly.. I see questions and answers about different topics involving from science to any other subject :)

[LiquidGold 1,370]

See! That's what I thought but the correct answer is supposed to be 15m/s.

But if you think about it logically, that answer is impossible, even if you leave out acceleration. Horizontally you get 60 meters in 4 seconds at that speed, with acceleration of 9.81 m/s^2 it will even be more.

They used this formula to get to that asnwer: x=x0 + v0t+ 0.5at^2 x = distance, v = velocity, t = time and a = acceleration.

--

my answer made the assumption that the object was falling at an even pace, if you bring in to the equation the object starts from rest is released then it falls you have to bring in acceleration and there fore the gradual increase in speed over that distance I am sure would mean it eventually would hit the ground at 15m/ps

Edited November 15, 2012 by LiquidGold

[LiquidGold 1,370]

Actually, if you refer to my reply, it was not quoted from everywhere :P

That's how I re-elaborated what I studied to give a reply :)

--

sorry for confusion I was saying my answer was quoted from Douglas Adams the "42"

[splitterpoint 10,986]

I often see cars with SDI...

now I know what TDI stands for (turbo diesel injection)

I also know what CDI stands for (common-rail diesel injection)

But SDI still remains a mystery; does someone know what it means?

[HichigoShiiro 4,378]

There is something called Google, Split. xD

 

http://en.wikipedia.org/wiki/SDI_(engine)

Edited November 15, 2012 by HichigoShiiro

[skitee 555]

I don't see philosophy, honestly.. I see questions and answers about different topics involving from science to any other subject :)

Orly?

Why do we excist?

What happens when Pinocchio says, 'My nose will grow now'?

Not religious... just scientific alone.

What's the meaning of life?

I'm sorry I'm asking you this; since there would no correct answer... but what do you think of it?

What colour is a mirror?

 

 

(I know the answer, I'm just asking) XD

 

^Those are all philosophical questions. <_< Science has a specific answer and can be proved by scientific equations and laws. None of those can.

Edited November 15, 2012 by skitee

[splitterpoint 10,986]

There is something called Google, Split. xD

 

http://en.wikipedia....iki/SDI_(engine)

 

Thanks; I couldn't find this on the dutch wikipedia :)

[Psycho 586]

Here's something hard

 

What is dichlorodiphenyltrichloroethane

[Guest]

 

Science is not only that, Skit :)

Science is everything you do everyday and everything you say every moment. Obviously, some questions/answers fall inside other subjects limits (like "why do we exist", it fall from science to philosophy).

Also, science is not limited to formulas and what you listed :)