Burning money

Hi all, have you tried to burn something but the item still exist.

Try this, you can use money notes (but not the Singapore new plastic note) for this experiment as it withstand heat better. Make 70% ethanol, dip your notes in the ethanol for a while, then light a fire to burn it. You can add some salt to make the flame more orangey instead of the blue flame which is not so visible.

Quickly give it a shake to extinguish the flame. You will notice the notes is perfectly fine. This is because the fire use the ethanol to burn, once the ethanol is used up, the fire will extinguish. 70% ethanol contain water so the water will be absorbed by the note (that why can't use plastic note) and the heat from the flame will be absorbed by the water instead of passing it to the note. Therefore the note will never be burnt. Unless you keep on holding the note under the flame as once all the water evaporate and the ethanol is used up, the flame will burnt the paper.

You can try dipping different item that absorb water into the ethanol but never try on flammable item. Enjoy the video that I shoot for this experiment.

How effective is the laundry ball?

Hmm so long never post new blog online because I did not found anything interesting. Now I found something interesting is the laundry ball. I saw the demo by the sale person and find it amazing as she claim that this ball can wash 1000 times (each time is 5kg load of cloth and wash for 30min). Two laundry ball cost only $30. Compare to my baby detergent which cost $6/kg and can only last for 2 mth is much more cheaper.

As I have a baby I am really concern on the type of detergent I use as I do not want my baby to have skin irritation. So I normally buy baby detergent which produce less bubbles to wash my baby clothes. However I do not like to use macine wash as I am afraid the detergent is not fully dissolved. However for this ball the detergent is in a form of pellets, when it is mixed with water, the detergent will dissolve out and you still can see bubbles.

So how effective is that ball which is so small and can wash for 1000 times? I can't check whether it can last for 1000 times or not cos it may took me 2 years before I can give you an answer. During the demo the person added dark soy sauce and iodine on a white cloth and it can be cleaned with the laundry ball in a washing machine. So I did an experiment using tap water, laundry ball, baby detergent and those concentrated washing powder with soy sauce, chilli and chocolate stain (I do not have iodine at home so I did not try on that).

To my surprise, tap water is good enough to wash soy sauce stain (so I don't really need the ball as demo by the person to wash those stain). Of course the rest are able to wash soy sauce stain too. I do scrub abit so hopefully my scrubbing is consistent for all the test.

After that I tried with chilli and soy sauce stain (again) and scrub the same no of time for all the test. Soy sauce stain can still be removed but for the chilli stain the best result is the normal concentrated detergent. Laundry ball and the baby detergent have almost the same result then the least effective is the tap water (result not shown cos it not very visible in photo).

Then I use chocolate stain and count the no of time I need to scrub to fully remove the stain. The best is still normal detergent which only need 70 scrubs followed by baby detergent which need around 90 scrub then laundry ball which is around 170 scrub the worst is tap water, after 200 scrub the stain is still not fully removed. Then I compare the colour of the detergent water at the end of experiment, the normal detergent water is the most dirtiest followed by the laundry ball, baby detergent then the tap water.

So in conclusion normal detergent is still the best but is gives the most bubbles and more soapy which mean that you need to rinse the clothes more times. But in term of economical wise laundry ball is the most economical if it really can last for 1000 wash and it has the least bubbles so you can save more water too as you do not need to rinse more. Then baby detergent is the least economical even though it has less bubbles compare to normal detergent but it is the most expensive one. So next time do consider trying the laundry ball as it leaves no powder residue (especially using machine wash, as sometime the detergent is folded in the clothes and not dissolved in the water). It is also convenient too, all you need is to throw the ball in the washing machine with your dirty clothes that all. No need to worry how much detergent to add. This is because with more load, the washing machine will add more water so more water will dissolve the pebbles and you will get more detergent for your wash.

However do note one experimental error in this experiment. I can put the same amount of washing powder for the baby detergent and normal detergent but I cannot control the amount of detergent that is dissolved into the water from the laundry ball. What I did is to soak the ball in around 2L of water for 10 min and took the water for this experiment. So who knows if I soak the ball longer, more detergent is dissolved out and it may even clean the stain better than those powder detergent?

After all, I have been using the ball for 2 weeks I am satisfied with the result. My clothes are cleaned and leave no smell too (not smelly but don't expect what lemon smell or detergent smell cos it don't contain those chemical that produce the smell). I tried to use machine wash but then I was too picky and have a habit to scrub my clothes. So I decided to soak all my clothes in a pail with that ball for around 30 min, scrub the clothes in another basin of clean water then throw all into the washing machine and start only the rinse and spin function. So I actually save more water cos I only use around 2 pail for washing compare to the wash function of the washing machine somemore it only stir my clothes so not sure whether it can wash the milk stain on my clothes or not.

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Why white shirt then to fluorescence when under UV light

I think most of you have ever been into dark room that contain UV lamp and you notice those white colour T-shirt will fluorescence. This is because modern detergents contain phosphors which convert UV light into white light. So when you wear your T-shirt under the sunlight your T-shirt will looks whiter than white which seem that your T-shirt looks clean. As the phosphor will convert the UV light from the sun to emit white light.

So next time you can try buying 2 brand new T-shirt, one washed it with detergent contain phosphor another just leave it unwash. Then put both T-shirt in a dark room with UV lamp, you will notice the T-shirt that has been washed will glow better than the one which is unwash.

How fluorescence light work

Hi, so long have not update my blog. Maybe I did not encounter any special science expt which I can write on. Finally, today I encounter one. My lab have a fluorescence light which half of it is with the white coating while another half is without the white coating. My previous lab tech have ever shown me that when that lamp is lighted up the part without the coating will not have white light. I did not bother to find out why that time but now I have to teach my new lab tech so I went to check out what is the theory behind it.

The fluorescent lamp is a sealed glass tube. The tube contains a small bit of mercury and an inert gas, typically argon, kept under very low pressure. The tube has two electrodes, one at each end, which are wired to an electrical circuit.

When the lamp is on, the current flows through the electrical circuit to the electrodes. There is a considerable voltage across the electrodes, so electrons will migrate through the gas from one end of the tube to the other. This energy changes some of the mercury in the tube from a liquid to a gas. As electrons and charged atoms move through the tube, some of them will collide with the gaseous mercury atoms. These collisions excite the atoms, bumping electrons up to higher energy levels. When the electrons return to their original energy level, they release light photons in the ultraviolet wavelength range.

As our eye cannot register ultraviolet photons, these light photons have to be converted into visible light with the help of phosphor which is the coating surrounded the tube. Phosphors are substances that give off light when they are exposed to light. When a photon hits a phosphor atom, one of the phosphor's electrons jumps to a higher energy level and the atom heats up. When the electron falls back to its normal level, it releases energy in the form of another photon. This photon has less energy than the original photon, because some energy was lost as heat. In a fluorescent lamp, the emitted light is in the visible spectrum -- the phosphor gives off white light we can see.

This is the reason why the part without the phosphor coating will not light up, as we cannot see UV light. Therefore it is also quite dangerous to look at that lamp as it is different from those UV lamp (black light). Those UV lamp have a black coating which is make up of different type of phoshor coating which absorb the harmful UVB, UVC and visible light but emitting benign long-wave UVA light with some blue and violet light. Whereas my lamp without any coating are emitting all UVA and harmful UVB and UVC.

Dancing Raisin

Hmm you like rum and raisin? Then have you tried 7up with raisin? Have you wonder why your raisin will "dance" in your 7up? It will flow up and down right? The theory is very simple, this is because the gas in the soft drink pushes the raisin up and when the gas bubbles pops, it will not be able to hold on to the raisin and the raisin will drop down.

It is best if you can get raisin that is very dry as the drier the raisin, the raisin will be more wrinkled and light so as to create more surface area for the gas bubbles to push the raisin up.

Alternatively if you do not have soft drink at home, you can try to put 2 teaspoons of baking soda in around 100ml of water, dropped your raisin inside and then add some vinegar into it. Effervescence will be observed once vinegar is added as vinegar which is an acid will produce cardon dioxide when react with carbonate. This carbon dioxide gas will forms into bubbles and pushes the raisin up.

So have fun and take a look at the video which I took myself that shows the raisin moving up and down.