1

Physiology & Medicine / What is colourblindness, and what's it like to be colourblind?

« on: 18/02/2007 13:25:55 »

What causes colourblindness, and what does a colourblind individual actually "see"?

G

2

Chemistry / Why are metals shiny?

« on: 12/02/2007 09:08:26 »

What is the chemical reason why metallic substances are shiny whereas non-metal solids tend not to be?

George

3

Physiology & Medicine / What is hypnosis and how does it work?

« on: 04/01/2007 04:20:43 »

Can people really be pursuaded to do something they don't want to, like give up smoking (!), or "remember" lost memories from childhood, as is alleged to happen sometimes?

4

The Environment / How fast is the Amazon rainforest disappearing? How long before it's all gone?

« on: 04/01/2007 04:19:31 »

How quickly are the Earth's rainforests being swallowed up, and how long before there is nothing left? What will be the impact on the planet's climate and the composition of the atmosphere?

5

The Environment / Will wind generators affect air circulation on Earth?

« on: 04/01/2007 04:17:44 »

If we build enough wind turbines, will this have a detrimental effect on winds around the Earth?

6

Physics, Astronomy & Cosmology / What is a "neutron bomb", and how does it differ from an "atom bomb"?

« on: 04/01/2007 04:16:45 »

People talk about nuclear weapons including atom bombs and neutron bombs, but what are they? What's a hydrogen bomb, for instance?

7

Plant Sciences, Zoology & Evolution / How much water does a tree use per hour?

« on: 04/01/2007 04:15:12 »

Plants draw water from the soil and release it through their leaves, but how much do they consume, per hour?

8

General Science / How do we know how much the Earth weighs?

« on: 01/01/2007 16:19:06 »

Scientists seem to have a pretty good idea as to the mass of the Earth, but how did they arrive at this figure?

9

Chemistry / How does washing up liquid work?

« on: 28/12/2006 17:18:42 »

How do washing up liquids and other detergents work to "cut through grease"?

Incidentally, this question occurred to me after I read this wonderful "top tip" in Viz:

"Makers of Fairy Liquid. Why not dilute your washing up liquid a bit. Then you wouldn't have to spend a fortune on television advertising telling everyone how concentrated it is."

10

Physics, Astronomy & Cosmology / How much solar energy could the Sahara desert produce if covered in solar cells?

« on: 28/12/2006 17:14:39 »

Since the Sahara is a very sunny place, is currently unused by anybody and probably doesn't have too many planning regulations, assuming we could exploit it, how much solar energy could it yield, and what would be the best way to collect this energy i.e. solar cells, Stirling engines, Venturi effect generators etc?

George

11

Physiology & Medicine / Maternal immunoglobulin (antibody) and the foetus

« on: 31/10/2006 23:13:17 »

I was reading about foetal development the other day and came across something that I couldn't understand; I hope someone here can explain.

From 30 weeks gestation, the placenta begins to transfer immunoglobulins (antibodies) of the IgG class from the mother's bloodstream to the baby. The aim is to provide the baby with "passive" protection against infection until its own immune system begins to work properly.

I know that the B cells that produce antibodies are "checked" to make sure that they aren't auto-reactive (don't lock on to our own tissues) before they are allowed to mature. But the antibodies are not checked against the developing baby's tissues, only the mother's.

So why don't the maternal IgG's start to bind onto foetal tissue and damage it?

12

Physiology & Medicine / How does a Hair Perm Work?

« on: 13/10/2006 22:59:03 »

How does a perm work? What does it do to the hair to make it curly, and why do some people have an "auto-perm" i.e. naturally curly hair?

George

13

General Science / How does Quick Sand Work?

« on: 07/10/2006 23:18:23 »

A film I saw recently contained the usual cliched quicksand situation where someone runs into a watery grave.

But what is quicksand, do you really drown or sink in it, and what's the best way to get out?

George

14

Physics, Astronomy & Cosmology / Glass and light

« on: 22/06/2006 04:03:54 »

Can someone please explain to me :

Why is glass transparent?

Thanks,

George

15

Chemistry / What happens when a pot is 'fired'

« on: 18/09/2004 11:08:24 »

When you make something out of clay and dry it, it goes hard, but easily falls apart if you make it wet again. But if you put it in a kiln and bake it, the pot becomes hard and water-resistant.

My question is, what happens when you 'fire' (bake in a kiln) an item of pottery to make these changes occur ?

16

Famous Scientists, Doctors and Inventors / Inventor of the Printing Press

« on: 22/01/2004 15:51:58 »

How was the printing press invented, and when, please someone ?

G

17

Chemistry / Why is sodium carbonate alkaline?

« on: 10/12/2003 21:00:33 »

Hi, can one of the chemists please explain the following (in simple terms !)

- I saw the other day that the alkali added to swimming pools to keep the water in balance is "soda ash" or sodium carbonate - Na2CO3. Why is this alkaline ?

I thought you needed hydroxide to produce an alkali, like lime (CaOH) or sodium hydroxide (NaOH)

George

18

That CAN'T be true! / E-bombs

« on: 27/03/2003 05:31:03 »

I heard a rumour the other day that classified weapons that affect electrical systems, disrupting computers etc, but don't hurt people, are being used in Iraq.

How do they work ?

George.

19

Physics, Astronomy & Cosmology / Wagon Wheels

« on: 04/11/2002 21:44:03 »

Whilst watching a crappy old "western" the other day my wife commented that the wheels on the carts go backwards. You never see this in 'real life' so it must be a trick of the camera presumably - but why does it happen ? Anyone know ?

Georgey[)]