Thursday, 31 January 2013

Not electroplating, it's chemical plating!


1. One cup of vinegar
2. A glass or transparent bowl
3. One tablespoon of salt
4. An iron nail
5. Twenty feet of a tightly coiled copper wire
6. An iron nail


1. Put one cup of vinegar in the glass bowl.
2. Now put one tablespoon of salt in the vinegar and stir it well to mix it well so that the salt dissolves.
3. Now rub the iron nail with the steel wool to clean it well. Rub it till the nail is well polished.
4. Now put the well cleaned iron nail in the vinegar and salt mixer.
5. Then also put the tightly coiled copper wire in the mixer.
6. Now observe what happens. Check the nail and the copper wire for changes after 1 hour, 2 hours, 4 hours, eight hours and finally after 1 day.


1. Over time a thin layer of copper is created on the iron nail.
2. Over time the copper wire should get more brittle and might just even dissolve a little bit.
3. If you touch the iron nail covered with copper the coating should come off on your finger.


This experiment actually demonstrates the practical example of the principles of immersion plating. The iron nail is immersed in a solution of metal ions. A thin layer of metal is created upon the iron nail. The mixer of vinegar and salt i.e. the vinegar salt solution actually makes it much easier for the metal atoms to transfer. In this experiment the vinegar salt solution or mixer acts as an electrolyte or the conducting fluid. In electroplating an electric current is used to transfer electrons between different metals. In this experiment it is shown that an electrolytic solution i.e. a conducting liquid fluid is just enough to create ion by releasing the copper wire electrons and then transfer them to the iron nail. But there is a big difference between electroplating and chemical plating. When a nail or a key is electroplated the coating stayed on very well even when handled. But when the nail or key is plated by using chemical the immersion plated coating comes off on the finger or hand rather easily. The reason behind it is that when electroplated, the metal atoms of the metal coating actually creates a bond with the metallic object which will be coated. But in chemical plating or immersion pleating this doesn’t happen. Chemical plating actually creates a layer over the metallic object which stays on because of the gravity. Because it doesn’t create any bond with the metallic object or in this experiment the iron nail the coating comes off rather very easily. In fact you may notice that at first the copper coating is created on only one side of the iron nail. If the nail isn’t turned to the other side that side won’t be plated. Just like electroplating, the copper source which is a copper wire in this experiment, looses electrons and forms copper ions that dissolves in the liquid conductor i.e. electrolyte. When the copper ions reach the iron nail they again gain electrons and form metallic copper. That metallic copper deposits over the metal of the iron nail.


1. Try this experiment to coat different kinds of metallic things such as screws, nuts, pipes etc.
2. Try this experiment using different kinds of sources of metals for coating such as coins, pipes, hinges etc.

How to do electroplating?

  1. An iron nail or brass key
  2. Dish soap and steel wool
  3. A plastic container
  4. Vinegar
  5. Insulated copper wire (Can be obtained from a hardware or electronic store)
  6. A strip of copper (Can be obtained from a hardware or electronic store)
  7. Wire strippers (Can be obtained from a hardware or electronic store)
  8. A six volt battery

  1. At first clean the iron nail or brass key with dish soap and the steel wool.
  2. Then pour some vinegar into the plastic container.
  3. Now add some salt in the vinegar and mix it well to make it dissolve.
  4. Now make an edge of the copper strip bend so that it hangs over the edge of the plastic container.
  5. Cut 2 pieces of insulated copper wire. Each piece of wire should be the length of about a foot.
  6. Strip both ends of each of the wires.
  7. Now wrap one end of one of the copper wires around the copper strip and wrap the other end around the positive terminal of the six volt battery.
  8. Then wrap one end of the 2nd wire around the iron nail or brass key and wrap the other end around the negative terminal of the six volt battery.
  9. Hang both the copper strip and the other object inside the plastic container. Make sure that both objects are particularly submerged. Also make sure that the opposite wires and the objects do not touch one another.
  10. Now observe what happens to the objects in the next one hour.

  1. After fifteen to twenty minutes the iron nail or the brass key should start to look a bit coppery.
  2. The iron nail or the brass key should be totally copper plated at the end of one hour.
  3. The copper strip should also change over time. When the copper strip is removed from the vinegar salt mixer or bath it feels quite brittle.

In our experiment when current passes through one metal loses electrons while the other metal gains that electron. The two different metals used in this experiment have different tendencies towards losing electrons. In our experiment Copper has much more tendency to lose electrons than iron or brass. That’s why copper is said to be the more active of the metals. The more active metal of the two acts as the anode and the less active metal acts as a cathode in an electroplating. But just losing or gaining electrons doesn’t actually explain how a layer of metal is transferred from one metal to another during electroplating. When the copper strip loses electrons copper ions are formed in a process which is called ionization. These copper ions are dissolved into the electrolyte which is the vinegar and salt mixer or bath in our experiment. At the cathode which is the iron nail or the brass key, positively charged ions can gain electrons. The metal in the iron nail or brass key didn’t get ionized so the only metal ions available to gain electrons are the ions of copper in the electrolytic bath i.e. the vinegar and salt mixer. When the copper ions gain electrons they once again become copper atoms. Because this process actually occurs in the cathode, the copper atoms deposited there. Over time a layer of copper will coat the cathode which is actually an iron nail or a brass key.
The reason for the copper strip becoming more brittle after the electroplating is finished is because this process actually takes copper out of the anode and deposits them on the iron nail/brass key/cathode. The longer the process of electroplating or copper plating is continued the the more the copper would dissolve and become more brittle.

Electroplating is really very important in our modern everyday life. You may not know but it is used in variety of ways. Cheap jewelry is electroplated with gold to make it look much more valuable. Car parts made with steel are electroplated with nickel. This provides the car parts protection from rust and corrosion. Also after electroplating with nickel the car is covered with chrome with this process to make the car look nice and shiny. Even the wristwatch, which are made of metal are electroplated for long lasting effects.

  1. Use nickel strip instead of copper strip.
  2. Do this experiment with copper at first and then replace the copper with nickel. Also leave the copper plated iron nail or brass key or the cathode in the electrolyte. After that do the same experiment with this. Nickel is actually much more active metal than copper. So observe if you get another layer of coat on the cathode or not?

Making the visible invisible again!


1. A Secret or invisible message written by using water and cornstarch mixer (See this blog: Invisible ink – 1) after making it visible by using tincture iodine.
2. A clean paintbrush
3. ¼ cup of saliva (Can be obtained by just only spitting into a cup!!!!! :D :P)


1. At first dip the paintbrush into the saliva and then paint over the visible letters in the secret message which is written by cornstarch mixer.
2. Observe if there is any change in the message.
3. If you don’t see any change in the secret message, then repeat the same process. This time perhaps use another person’s saliva.


1. Over time the dark purple letters which was visible after using the tincture iodine might fade and become invisible again.
2. Your saliva might not just make it invisible again coz some peoples saliva do not actually work on those dark purple letters written by cornstarch mixer.


In the human body many different kinds of foods are broken down. Different kinds of proteins are responsible for the breaking of these foods. Many of these foods are actually found in the saliva. The protein which is responsible for breaking down proteins is called amylase. This protein named amylase is found in the saliva as well as the intestines and stomach. Amylase is an enzyme. So it can be used over and over again to convert or transform starch into a substance or molecule which the body can easily use. This enzyme breaks down starch into sugars. Sugar is a much are simpler molecule than starch so the body can easily use it. When saliva is added to the secret or invisible message any amylase in the saliva will transform the starch used on the paper to write the invisible message into sugar. When starch on the secret message is transformed completely into sugar the dark purple color of the letters written in the message disappears and the secret message i.e. the invisible message becomes invisible again.
Now to answer the question - why saliva of some people doesn’t work on starch? The answer is simple! Saliva of some people doesn’t actually contain amylase. So that’s why saliva of those people is unable to transform or convert starch of the visible secret message into sugar. The dark purple color of the letters of the secret message will not be affected and so they won’t become invisible again. The presence of amylase in ones saliva is actually genetically determined. So the chances are really great that his/her parent’s saliva also do not contain amylase. So if your saliva do not work in this experiment try using one of your friends or neighbors saliva. in short you should get saliva from an unrelated person if your saliva do no work on the secret or invisible message written with starch.


Try using the saliva of different house pets such as cats or dogs to see what happens. But be really very cautious about it and be really very careful.

Sunday, 27 January 2013

Invisible ink – 2


1. A lemon or lemon juice
2. A cup or a bowl or a container
3. A piece of paper
4. A paint brush or a piece of cotton
5. A lighter or a burner


1. At first slice the lemon and squash it to get lemon juice from it. Contain the lemon juice in a cup or a bowl or a container.
2. Then dip the paintbrush into the cup/bowl where you have put the lemon juice.
3. Now use the paint brush to write anything on the paper. (Usually it’s a secret message because the writing is invisible! :p)
4. Let the writings dry on the paper.
5. Now light the lighter or the burner and place the paper containing invisible secret message near the fire. Be very careful not to let the paper on fire. Just make sure that the paper will get quite a bit of heat from the lighter or the burner.
6. Now observe what happens.


The more heat you give the paper the more your writings become visible again. Eventually your invisible or secret message will not be an invisible or secret message anymore. It will be completely visible.


When we write use lemon juice on the paper and let it dry the areas of the paper which contain lemon becomes more sensitive or vulnerable to heat. So the area of the paper containing lemon juice takes much less time to be heated. In simple words it takes much less time to burn the areas of the paper containing lemon juice. So when we place the paper close to a lighter or burner fire i.e. give it heat the areas containing lemon juice burns much more than the areas not containing lemon juice. Because the areas containing lemon juice burns more than other places of the paper or they become darker. That’s why the lemon juice writings become visible again. Sometimes only the areas containing lemon juice burns and the rest of the papers remain unaffected.


1. Try this experiment using vinegar to see what happens.
2. Try this experiment using Orange juice to see what happens.
3. Try this experiment using Onion juice to see what happens.

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