Tuesday, December 23, 2008
Fire piston
A fire piston is a device of ancient origin which is used to kindle fire. It consists of a hollow cylinder ranged in size from around 7.5 cm to 15 cm long, sealed at one end and open at the other. A piston which is about 1-2cm in diameter, can slide into the cylinder forming an airtight seal with the cylinder wall. The piston has a handle on the end to allow a firm grip to be applied to it and can be completely withdrawn from the cylinder.
The piston must be rammed quickly into the sealed cylinder with a single stroke. The compression of the air causes the temperature to rise rapidly to 260 degrees Celsius. This is hot enough for the cotton wool inside the piston to ignite. It can then be withdrawn and transferred to a larger mass of kindling to create a fire.
The principle of fire piston works based on rapid compression of the air (known as adiabatic compression) increases its pressure and its temperature at the same time. If this compression is done too slowly the heat will leak away to the surroundings as the gas returns to equilibrium with them. If the compression is done quickly enough then there is no time for equilibrium to be achieved and the absolute temperature of the air can suddenly become several times that of its surroundings, increasing the original room temperature of the air to a temperature hot enough to set the cotton wool alight. The air in the cylinder acts both as a source of heat and an oxidizer for the cotton wool.
Making glue from milk
5) These curds is also known as casein and it is then dried on filter paper (as shown).
7) Finally add 1.5g of calcium hydroxide powder and stirred until a thick creamy liquid is form and this will be the glue.
I tried to leave it for a few days in a covered container and it does not dried up even it is dried just add a drop of water and stir the glue can be used again. Another good thing is that it do not have any glue smell so it is quite safe.
So hope you like my receipe if you are currently unsatisfied with your glue. Try to make one yourself.
Monday, October 27, 2008
Conductor and insulator of electricity
The reason is thatin conductive materials, the outer electrons in each atom can easily come or go, and are called free electrons. In insulating materials, the outer electrons are not so free to move.
All metals are electrically conductive.
Electric current is the uniform motion of electrons through a conductor.
In other types of materials such as glass where atoms' electrons have very little freedom to move around. While external forces such as physical rubbing can force some of these electrons to leave their respective atoms and transfer to the atoms of another material which form the static electricity which is an unmoving, accumulated charge formed by either an excess or deficiency of electrons in an object.
For electrons to flow continuously (indefinitely) through a conductor, there must be a complete, unbroken path for them to move both into and out of that conductor.
Here will be some of the example of conductor and insulator.
Conductors: silver, copper, gold, aluminum, iron, steel, brass (copper & Zinc), bronze (copper & Tin), mercury, graphite, dirty water, concrete
Insulators: glass, rubber, oil, fiberglass, porcelain, ceramic, quartz, (dry) cotton, (dry) paper, (dry) wood, plastic, air, diamond, pure water.
Saturday, October 18, 2008
Protein analysis
Tuesday, October 7, 2008
Will electricity bypass a resistance?
Wednesday, October 1, 2008
The Pulley System
Hi encounter pulley system while teaching my tuition gal on forces and simple machine. So went to check out how to know the effort needed to lift the weight in different pulley system.
The mechanical advantage of each system is easy to determine. Count the number of rope segments on each side of the pulleys, including the free end. If the free end is to be pulled down, subtract 1 from this number. This number is the mechanical advantage of the system! To compute the amount of force necessary to hold the weight in equilibrium, divide the weight by the mechanical advantage!
Example in P=W, there is 1 string attached to pulley and 1 free end. Total no.s of rope segment will be 2 but it is being pulled down so substract 1. Therefore the effort needed is Weight / (2-1) = Weight/ 1. So force needed is the same as the weight.
In P=1/2 W, there is 1 string attached to pulley and 1 free end but is not being pulled down. So effort needed is Weight / 2, therefore you will only require half of the effort to move the weight.
In P= 1/4 W, there is 4 string attached to pulley and 1 free end, but it is being pulled down so substract 1. Therefore the effort needed is Weight / (5-1) = Weight/ 4. Therefore you will only require a quarter of the effort to move the weight.
Anyway special thanks to SWE organisation which gives such easy to understand formula to let us learn about pulley system. Those who want to test yourself on pulley system can also go to this link http://www.swe.org/iac/lp/pulley_act.html. Hope you have learn a lesson on it.
Sunday, September 7, 2008
Fruits growing on tree trunk?
Hi all, haiz school holiday I even more busy, can't even try experiment as teacher also did not come and look for me so also no strange experiment to try out. Anyway just want to share with you all about this amazing thing. My father-in-law actually pass by along Holland Road and saw fruit growing on the tree trunk. As mentioned by him, this tree is about 10M tall and the fruits is growing from the bottom of the trunk to the top. Initially he thought people stick the fruit on it but then he had a closer look, the fruit is really attached to the trunk as if it grows out from the trunk. If you do not believe go and see yourself. Is somewhere along Holland Road outside the Botanical Garden. Anyone who know why is like that can also post some comment for me so I can understand about this tree better.
Tuesday, August 26, 2008
A Cat give birth in my lab
Then I put the kitten properly in a basket with newspaper and the kitten just sleep there. I really don know what to do with them now. Hopefully their mother will come back and feed them if not they will strave to death as I am not sure cow milk is suitable for them or not cos they are too young to eat anything. I scare if I give them the wrong food I may end up poisoning them.
Wednesday, August 20, 2008
Batteries arrangement
Friday, August 15, 2008
Is chicken egg fertilized internally or externally?
Wednesday, August 13, 2008
Parallel or series (electric circuit) ?
I knew that most of our electric circuit in our household are connected in parallel. I remember that as I know when connected in parallel, if one of the appliance is spoil it will not cut off the circuit so the rest of the appliances can still be work.
Another reason I also found out after conducting the above experiment. Appliance do have resistance itself. When connected in series the resistance is added up together. (Example if I have 3 appliances with 20 ohm resistance each, the total resistance of the circuit will be 60 ohm). However to calculate the resistance of a parallel circuit we uses 1/R (R=resistance). Which mean if the scenario is the same as above, when connected in parallel the total resistance is 1/20 X 3 which is 3/20 ohm.
So you see it? 3/20 ohm compare to 60 ohm no wonder my bulbs cannot like up when connect in series and it is really a waste of electricity as all my current are block by the high resistance. So remember if you want to set up a circuit which need to connect with a lot of appliances make sure you connect them in parallel in order for it to work more efficiently.
For those who have never study physics or science before, please find out yourself how a parallel and series circuit look like ;)
Anaerobic respiration
Tuesday, August 12, 2008
Making your own lava lamp
Hmm I have tried this before but is not using what is written in the website. They uses Alka-Seltzer tablet which I am not sure what is that. Should be those fizzy tablet that can be dissolve to make a drink. You can click on the link and follow their procedure.
My way is to add oil to fill up 1/2 of the conical flask then add vinegar (with food colouring to colour it) to fill up to 3/4. I do leave some space as when it bubbles the carbon dioxide produced need space. I also did not cap it as the carbon dioxide produce will push my cap/stopper out. So I am not sure why they can cap the tube. Most probably the reaction have ended, but then if ended you can't really see bubbles in the oil unless you shake it. Add a few spatula of baking soda into the mixture. It will react with the vinegar to make tiny bubbles of carbon dioxide gas. These bubbles attached themselves to the blobs of coloured vinegar and cause them to float to the surface. When the bubbles popped, the colour blobs sank back to the bottom of the bottle. This look like a lava lamp which does not cost you much. So try it out yourself!
However the cons is that it only works if you add in the baking soda or the fizzy tablet and there is a saturation point where additional of these substance will not produce the cardon dioxide anymore.
The theory of quicksand
I think most of you know quicksand is a gooey stuff that grabs a hold of its victim and swallows them alive! So, what is quicksand and how does it really work? I learn this from a teacher and happen to find a website that exactly describing this experiment, therefore to know more info on it just click the link and I think there is a video on it too.
This theory can be shown in a simple experiment. Firstly, get a cup of cornstarch (easily available in the supermarket) pour it in a shallow plate. Add half a cup of water slowly to the flour and mix it until you get something like the picture on the left. If is too watery you can add more cornstarch or just left it there to dry (but take a longer time). Remember this will dry up to form a solid so never pour this in the drain and clog it. Throw it in a rubbish bin. However you can also keep using it by adding water to it so you do not need mix it again to show this experiment.
You can try to punch your mixture, you will feel that it feel like solid as you are forcing the starch molecules to become close together as water is trapped between the starch chain. When you just touch gently, the cornstarch will flows again.
All fluids have a property known as viscosity - the measurable thickness or resistance to flow in a fluid. Newton said that viscosity is a function of temperature. You can observe that heated honey has viscosity less than the cold honey. The cornstarch and water mixture and quicksand are both examples of non-Newtonian fluids because their viscosity changes when stress or a force is applied and not due to the temperature.
Quicksand is created when water floods or saturates an area of loose sand and the sand is begins to move around. Think of quicksand as a soupy mixture of sand and water that is constantly being stirred. When the water in the sandy soil cannot escape, it creates a liquid-like soil that can no longer support any weight. If an excessive amount of water flows through the sand, it forces the sand particles apart. This separation of particles causes the ground to loosen, and any weight on the sand will begin to sink through it.
So this experiment is to shows the behavior of quicksand, as the cornstarch is like the sand which is flooded with water. This also tell us that when we encounter quicksand do not force yourself to get out of it as the greater the force you applied the harder the sand will be and your leg will get stuck even more. So one way is to relax wait for it to soften then move it out. Another way is to lie on your back to keep yourself afloat and slowly paddle. Actually I saw this in the website however I don't really encourage it as who know you may get panick and increase your force end up you may sink even more.
Friday, August 8, 2008
Endothermic reaction
Today this experiment is to show that when 2 chemical react the endothermic reaction can actually freeze a thin film of water on the wooden block and then the beaker can actually stick onto the wooden block.
This experiment is very easy. All you need is Barium hydroxide (app 2-4g) and Ammonium thiocyanate (app 2-4g). Mix both together with a bit of deionised water soon (ard 1min), you can see that the film of water actually freeze and stick on the beaker. (definately is not surface tension as we tried to push the block slightly, it still will not drop).
We tried subsituite Barium hydroxide with Calcium hydroxide but it will not work even though you can feel the coldness around the beaker. So try it out yourself if you do not believe it.
Wednesday, August 6, 2008
Is that magic?
Is amazing right? But is not a magic, it is due to some chemical reaction which allows it to change colour continuously. Firstly have to special thanks to NUS High School as this experiement is learnt from them.
To do it, you need to have license to purchase the chemical and you have know how to calculate concentration of the solution. As the concentration of the solution is important to allow the reaction to happen. Lastly, I have to apologise that my video is not vertical as I do not know how to adjust the video from my blog. The video is actually showing a conical flask on a magnetic stirrer and it will continue to change colour without adding anything to it.
So to perform this "magic" you will need to prepare 3 kind of solution (solution A, B, C).
Solution A : 4M of hydrogen peroxide
Solution B : Add 21.5g potassium iodate, add approximately 400ml of distilled water and finally add 2.15ml of concentrated sulphuric acid and then top up to 500ml with distilled water. This gives you 500ml of solution with 0.2M potassium iodate in 0.077M sulphuric acid.
Solution C : Dissolve 8g of malonic acid and 1.7g of manganese (II) sulphatemonohydrate in approximately 25oml of distilled water. Add in 30ml of 0.5% soluble starch solution into the mixture. Finally top up to 500ml with distilled water. This will gives you 500ml of solution with 0.15M malonic acid and 0.02M manganese (II) sulphate.
500ml of each solution is made. However if you do not have such a big conical flask (need at least 2L conical flask). You can just take 200ml of each.
Firstly we will mix 200ml of solution A and 200ml of solution B into a big conical flask with magnetic stirrer. Keep stirring it and then pour 200ml of solution C into the mixture.
This step will start the magic, the solution will turn from colourless to amber and then blue black. The exact theory is not known. But it is may due to the hydrogen peroxide causes the iodate to become iodine so the solution turns form colourless to amble or brown. Then the iodine will react with the starch present to turn the solution to blue-black. However I am not sure why it turns colourless again, maybe the iodine will dissappear again and later come out again? Anyway this reaction do not last forever. It will remain dark blue after stirring for more than 10 min.
A silicon jungle
My circuit experiment
Circuit with a magnet
Sunday, August 3, 2008
Add vinegar when dyeing egg?
Based on the above theory, vinegar which is acidic in nature provides hydrogen ions (H+) which combine with the amino group (NH2) to form NH3. This create more reactive sites for salt linkage. Whereas if the dye is alkaline,less dye will be adhered to the egg.
If you do not believe, try this at home. Add 100ml of vinegar, 10ml of dye and top up with water to 500ml. Make another pot of dye using only 10ml of dye and top up to 500ml of water and the last one by adding 5g of baking soda with 10ml of dye and top up to 500ml of water. This experiment is to test whether the pH of the dye will affect the colour of the egg. You should get a darker egg when it is soaked in the pot with vinegar and the lightest egg will be the one that is soaked in the dye that contain baking soda.
Saturday, August 2, 2008
A kit to tell whether your foetus is boy or girl?
It works by mixing your urine with a conjugated antibody (or we can say an antibody that gives a signal). If your urine contain hCG, it will bind to the antibody and then attached itself on the immobilised antibody that is embedded on the front of the kit and this conjugated antibody will show a band at the area.If there is no hCG, these conjugated antibody will continue to flow toward the end of the pregnancy kit and bind on the antigen (can be human Chrionic Gonadotrophin) that is embedded on the kit. This will shows a band at the end of the kit which is the negative control. In conclusion, it tells us that if 2 bands are shown, congratuation! You are pregnant. But if only one negative band is shown mean you are not pregnant. If no band is shown mean that this kit is not working as it may not have enough conjugated antibody to show the signal.
So after pregnant, sure anxious about it sex right. Forget about those ultrasound scan which is so difficult to see and not specific. Now there is a kit where you can know the sex of your baby when you are just 10 week pregnant. I am not sure whether this kit is sold in Singapore or not as I just happen to see it in the net. It determine the sex of the foetus by looking for the Y chromosomal DNA in the mother blood using real time PCR. For your information, a male foetus have XY chromosome and female foetus have XX chromosome. So aren't we detecting mother cell instead of baby cells? No. It is because fetal cell will die and pass into the bloodstream of the mother. Furthermore mother do not have Y chromosome, so once Y chromosome is detected, it can be sure that it is from your fetus. For those who are interested to buy you can visit this website: http://www.tellmepinkorblue.com/. I am not sure whether they import to Singapore or not but is really not cheap (cost USD244). If really too much trouble then just wait patiently and let your doctor detect for you bah:)
Glofish
Hello. Are these fishes nice? It may look normal in this picture but do you know that it will glow in the dark.
These fishes are known as glofish®. They are available in three stunningly beautiful colors: Starfire Red™, Electric Green™, and Sunburst Orange™.Scientist create them for research. They originate from zebrafish. Zebrafish have been used in the genetics, molecular biology and vertebrate development. It also help scientist to understand cellular disease, cancer and gene therapy.
It is created by adding a fluorescence gene to the zebrafish gene in the fish egg. Once developed, the fish will then mature to become a fluorescence fish and their offspring will also inherited the gene and will also fluoresce. At this moment, this fish will fluoresce continuously. Researcher is now undergoing research to make this fish to detect the presence of environmental toxins in the water. They hope to produce a fish that will fluoresce when the water contain toxin and when the water is safe, it will not fluoresce.
However it is not sold in Singapore however from their website it mention that they do work with Carolina Biological Supply Company and I do know a saleman from there. But I did not ask whether he can import the fish for us or not as I do not intend to buy. Anyway here is just a brief introduction on glofish which I happen to know and share with you all. For more information, you can go to this website : www.glofish.com and also special thanks to them for the picture of the glofish.
Friday, August 1, 2008
More about me
I work as a lab technician in a high school located at the west of Singapore. I have encounter lots of interesting experiment either from internet, propose from teacher or from books. I great thing about my job is that I can have the access to all those chemical which cannot be bought on the shelf (as chemical are hazardous, only with license or for academic purpose then is allowed to buy).The reason I post it on my blog is to allow more people to be more interested in science and it is such a waste for not sharing my smart brain with others to make them smart.
It also allow me to have a chance to interact with people with interesting experiment too. So that I can propose them to my science head and they may think I am real too smart.Hahaha. So don be stingy if you come across any interesting experiment share it in my blog with other and let us become SMARTER kids.Oops forgot that it has been years that I am not a kid anymore. Hee hee sorry still so thick skin to called myself a "kid".