1

Chemistry / Test for Barium Hydroxide?

« on: 18/04/2011 11:13:53 »

Here is the question..

A solution, giving an apple-green colour to a flame, was suspected to be aqueous barium hydroxide.
Describe two simple tests to confirm this conclusion, giving the result of each test.

Now, I've only been taught that to test for Barium ions you do a flame test, which gives an apple-green colour!
Do I do litmus to test for alkalinity?

2

Physics, Astronomy & Cosmology / A Bungee Jump Question!

« on: 15/04/2011 10:05:48 »

Thanks for the help everyone []

A 'bungee jumper' standing on a high platform above the ground is attached to a bungee cord of unstretched length 26m and spring constant k. When she jumps she falls a maximum distance of 96m where she is momentarily stationary at the lowest point of her jump and begin moving upwards. Ignore air resistance.

Then there's a graph of Tension against Extension.

i) Using the graph, calculate the elastic potential energy stored in the bungee cord when the jumper is at the lowest point.

Is that by working out the area under the graph? Which I got to be 56,000J

ii) Initial gravitational potential energy (with respect to ground) possessed by the jumper on the platform is 7.0 x 10^4J and her mass is 60kg. Calculate how high she is above the ground at the bottom of her fall.

Here, I did mgh = 7.0x10^4 and got h = 118.9. I then took away 70m as that was the highest extension as shown on the graph.

iii) After bouncing a few times, the bungee jumper eventually comes to rest hanging a distance, d, below the platform

Now I'm shtuck [] Have I got all the bits before right?

3

Physics, Astronomy & Cosmology / A Physics Question..

« on: 15/04/2011 09:23:43 »

If you have a passenger inside a train, and he drops a ball.. If you neglect air resistance, would the ball be horizontally motionless to the passenger?

4

Physics, Astronomy & Cosmology / Why is high-pitch noise harder to distinguish where it's coming from?

« on: 04/04/2011 12:08:44 »

There was a really annoying high-pitched noise coming from our house, and I could not find where it was coming from! Now, if it was a low-pitch noise, like a low humming, it is so easy to find its origin. But what makes it different for a high-pitch noise?

Its high frequency and short wavelength? Even so..?

5

Physiology & Medicine / Tonsillolith - How to get rid of them?

« on: 03/02/2011 18:53:55 »

Well. I have been getting these yellow lumps (usually 1-2mm in size. Sometimes 3-4mm) from the back of my throat. I can usually feel them in my throat as its a bit irritating, and I can also smell them when they are in the back of my throat. It is a rancid smell.

I was a bit embarrassed by this and was genuinely like "What the beep!" when I first found out I was coughing up these yellow lumps. I usually get them once a week or so.
After a few years of this, recently I decided to google it, in little hope of finding someone with the same situation as myself. To my surprise, I found out that it is rather common, and they are called Tonsil stones or Tonsilloliths.

After seeing the Wikipedia page, I decided to look at my throat in a mirror, and I actually found a little lump embedded in my throat and I picked on it, and it came out with much ease.

Now, my question is. How do I get rid of them? I want to stop them forming altogether. Is it the food I eat? Would gargling help? They just smell terrible! I can feel one in the back of my throat as I type.....

Thank you! [:-[]

6

Just Chat! / Looking for Work Experience

« on: 01/02/2011 17:18:30 »

Hello all..

I'm not sure if any of you remember me, but I used to be on this site regularly a few years ago..
I hope Karen and Neil are still around..

Well, I have been busy with exams and whatnot, and I've finally gotten to the rotten age of taking even more exams and preparing myself for university etc.

I have been good with my exam results and such (the academic side) only to realise now that my extra-curricular stuff is rather blank!

I'm looking for some work experience, and the only one that I have done so far is work for a local newspaper. I'm looking for jobs preferably towards the bank sector, as I plan to study Maths at university and looking to become an investment banker.

I have tried getting work placements for many banks, but they do not seem to offer work experience for undergraduates. I have been told that if you have contacts at banks, then it may be easier to apply.

So I was wondering whether anyone could give me a hand with looking for work experience? Perhaps some contacts etc.. Or rather, where else I could apply for work experience, with ease, that would strengthen my university application (taking into account Maths)

Thanks for your help!

P.S I live in the UK, so somewhere near London would be great.

7

Physiology & Medicine / Feels bloated having eaten very little...

« on: 25/03/2009 19:55:53 »

Hi,

My dad regularly gets this thing where he feels bloated having eaten very little.
I'm worried for him and he won't go to the doctors about it, even though I've been pestering him that it might be something big..
He's not slim because of it - he's rather quite fat and has a big belly.
He still has a big dinner, but regularly he says after eating a snack (such as a muffin) that he's bloated! (This is not straight after a meal)

Could this be something?

8

Geek Speak / My school uses proxy server for the internet.. How can I use a program that..

« on: 11/01/2009 20:54:45 »

How can I use a program that requires the internet to run?
I try, and it says "No network connection. Connect to the internet" or something like that. I think it's because either it can't log into the Proxy because it requires a password, or I need to open a port in the firewall? If it's the latter, I don't know which port the program requires for it to work!

Thank you for your help []

9

Just Chat! / Home-Made Bicycle Lock!

« on: 07/01/2009 17:01:21 »

Make your own bicycle lock.
It can be lighter, cheaper, and much more fun than any lock you can buy.

Here's one made of cardboard!
It's perfect for use in Japan and other nice places where people don't like to steal.

10

Just Chat! / Milk Chocolate, Dark Chocolate, White Chocolate?

« on: 06/01/2009 16:31:06 »

 []

11

The Environment / How could CO2 be sequestered underwater?

« on: 06/01/2009 16:21:31 »

I read in the newspaper that scientists have figured out another way to trap CO2 under the sea from the atmosphere.

The research goes that as the ice caps are melting, there seems to be tiny iron particles in the ice which are melted back into the ocean.
The algae then "eats" the iron particles and blooms, resulting in them rising to the surface of the sea.
The risen algae photosynthesises and takes in Carbon Dioxide.
The algae then sinks to the ground, and stays there for a couple of hundred years!

Well, it seems that the Earth is trying to help itself, and that the CO2 which is taken in from the algae is actually a large proportion.

However, scientists and researchers are figuring out whether they should place tons of iron into the sea, making the algae bloom and thrive to the surface of the sea. Good idea it seems.
But they are worried that the placing of iron in the sea will destroy the natural ecosystem. More iron particles means more algae, which means more fishies that thrive on algae.. and etc etc...

What shall we do?!
Seems a pretty good idea.. but the ecosystem!

12

General Science / Someone told me that Hot water is quicker to freeze than Cold water...

« on: 06/01/2009 12:39:11 »

Is this true?

I would have thought the other way.. Because as the hot water cools, surely it would eventually reach the temperature of the cold water, and thus it would take longer?
Or is my friend  wrong?

13

Cells, Microbes & Viruses / Viruses and Bacteria.. What's the line between living and non-living?

« on: 05/01/2009 23:16:07 »

I understand that bacteria has a nucleus, whilst a virus doesn't.. But viruses still multiply themselves and seems to have a want to live. Surely that makes  them a living thing?

14

Technology / Why does our boiler keep banging and clanging??

« on: 05/01/2009 23:13:02 »

Whenever we turn the boiler on (central heating system of my house!) it makes this very loud clanging and banging that vibrates our house.. about 5 clangs per go, and about 5 gos per switching on the boiler!

Why do you think this is? Also, I think it's coming from the attic, or our boiler room.. We've had engineers to come look, and they say they solved it, and it still does it!

15

Physiology & Medicine / Why do I shudder just after starting to pee??

« on: 05/01/2009 23:05:43 »

 []

16

Physiology & Medicine / What causes joints to crack?

« on: 05/01/2009 23:03:41 »

The joints clicking.. Usually knuckles and knees..
Why is this? I have heard that it is because it releases air trapped between the bones, creating this crack.. But is it bad for you? Or leads to athritis?
Thank you!

17

Technology / We have good Technology - Do we have plantable teeth??

« on: 14/04/2008 20:49:06 »

Do we have plantable teeth?? Like a seed you insert in your gum per tooth.. And you have a new set of teeth?

18

Physiology & Medicine / Why do fingernails grow faster than toe nails?

« on: 09/04/2008 10:28:02 »

Is it to do with the blood circulation around the body?

Because less blood flows through the toe?

19

Technology / How do traffic lights detect the approach of a car? Do they use magnetism?

« on: 07/04/2008 22:19:26 »

Is it true that traffic lights work by realising a bigger magnetic field when a car approaches??

Because apparently there is a coil underneath the ground..  And when a car pauses over it, it works as the core, and produces a bigger magnetic field.. Thus changes the traffic light signal!!

Is this how it works??

So then, would you need to dig up the whole ground to put some sort of coils underground?
Surely this would be an expensive procedure?

20

Geek Speak / Volume sign in the bottom right corner of my screen!!

« on: 07/04/2008 22:12:10 »

I have Vista..



And you see that volume speaker thing on the bottom right hand screen?/

Well, however low I push the volume button on my laptop, it will always have 1 small line next to the picture, which means that it is still on small volume!!

I can  reduce the volume only to that point! so I either have to double click on the icon and reduce it, or just press mute..

Does anyone know why?