Salt water

We all are familiar with different types of batteries and use them in daily life. A battery is a device that stores chemical energy and converts into electric energy. The chemical reaction within the battery triggers a stream of electrons from electrode to one, via an external circuit. When electrons flow through a conductive path such as copper wire is called electricity. The path through which it travels is called the circuit. There are three major parts in a battery; anode (-), cathode (+), and the electrolyte. The cathode and anode are located in the surface of a conventional battery and linked to electrical circuiting this experiment we will learn how electricity is produced inside a battery, with the aid of salt and water. High concentration of salt in water is called brine water.

Table of Content

  • Purpose

  • Requisite of materials

  • Process

  • Result

  • Chemical Reaction

  • Types of Batteries

  • Conclusion


The main plan of this experiment is to know the components of the battery, how electrons flow in a battery, and the effects of the production of electricity. You are already acquainted with various utilization of battery in everyday life. Let us start the experiment.

Requisite of Materials

  • Salt

  • Copper wire

  • Tape

  • Zinc covered nails

  • Graph paper

  • Two insulated wire with alligator clips

  • Voltmeter

  • Glass jar small size

  • Water

  • Tablespoons


Step i- First, make a saline solution. Fill the jar with a small quantity of water, add two or three pinches of common salt, and stir well to prepare the solution.

Step ii- Submerge the zinc covered nails in the solution.

Step iii - Fasten the nail to one side of the container; it would be a negative (-ve) electrode.

Step iv- On the dangling end of the zinc covered wire, which is falling outside the jar, add an alligator clip.

Step v- Remove the alligator clip by pressing.

Step vi- Affix the alligator clip of the cable to the negative (-ve) terminal of the voltmeter.

Step vii- Hook up the copper-covered nail to the positive (+ve) terminal of the voltmeter. To perform this, replicate the same process that has been described above for zinc covered nail.

Step viii- Study the voltmeter reading, and record it in the paper, which shows the quantity of electricity transmitting between the electrodes.

Step ix- Add more salt in the solution and record the reading. Repeat the same process to record the difference in the voltmeter reading.


You can see the difference in the voltmeter reading; plot it in the graph paper for visual reference. In the graph plotting, you will see a point where the flows of current cease to increase.

Chemical Reaction 

There are two electrodes; the positive and the negative, which is separated by a chemical electrolyte, which in this experiment was liquid, the salt water. But the batteries which we use in daily life, the electrolyte are a dry powder. When you switch on the electrical device connected to the battery, the chemical reaction starts. The reaction creates positive ions and electrons on the negative electrode. The positive ions run into the electrolyte, and the electrons transmit through the circuit to the +ve electrode to light up the device. In the +ve, a chemical reaction is occurring, whereas the arriving electrons merge with ions, emitting out of the electrolyte to complete the circuit.

The chemical reaction occurring inside the battery causes the electrons and ions to flow, usually; both particles flow simultaneously. The nature of the reaction depends on the materials used to made electrolytes and electrodes. There are many types of batteries, but modus operand remains more or less the same. The electrons flow to the outer circuit and the ions react with the electrolyte (touching into it or out of it). As a battery continues to breed power, the chemicals get converted into different compounds. Their capacity to produce power decreases, the voltage gradually falls, and ultimately the battery runs flat. As the chemicals get exhausted, and it cannot create +ve ions, neither it can produce electrons, which would have flowed to the external circuit.

Types of Batteries

You will find different types of batteries depending on the dimension, contour, voltage, and capacities (amount of store charge/energy). Chemical composition and materials of electrolytes and electrodes can vary, but there are two significant types of the battery; primary and secondary. Primary ones are which are not rechargeable; you have to dispose of it after it gets exhausted. The secondary ones are researchable. You can recharge it by allowing the current to move in the reverse direction, to which it usually flows while discharging. This feature of recharging makes all the difference between primary and secondary batteries. When you put your cell phone on charge, you are permitting the current flow and chemical reaction in reverse.  

Primary Battery

You might assume this type of battery are old styled and not environment friendly as you have to discard it after it runs flat. But they have more storage capacity and lasts for a more extended period, compared to rechargeable batteries of the same capacity. Disposable lithium batteries are used to power heart pacemakers. It is absurd and preposterous to open a patient`s chest to recharge the battery. On many occasions, disposable batteries are indispensable.

Primary batteries come in three forms; alkaline, lithium, and zinc-carbon. Since the electrolyte is solid, it is also referred to as the dry cell.

Zinc Carbon

It is the most common, the cheapest battery used in everyday use to power flashlights, radios, and clocks. French inventor Georges Leclanche invented zinc-carbon battery in 1865. The carbon rod enclosed by manganese oxide and dust carbon acts as a positive electrode. The negative electrode (the external casing) is made up of zinc alloy. A glue of ammonium chloride inside the battery is the electrolyte.

Alkaline batteries look much similar to a zinc-carbon battery, but last much longer and storage power. The +ve electrode is made of manganese oxide, and –ve electrode is made of zinc. Concentrated alkaline solution (potassium hydroxide) is the electrolyte of the battery.

Button batteries function similar way, that of ordinary alkaline batteries. The electrodes and electrolyte material are also identical to that of zinc carbon batteries, while others use lithium and other organic electrolytes and function through diverse chemical reactions.


Batteries are very similar to boxes, the bigger the size of the box, the bigger space within. The size of the battery determines how much energy it can store within. Batteries with large sizes accommodate bigger electrodes and more electrolytes generating more power. AA, AAA, C, and D sized battery comes with 1.5V, but in a different dimension. Larger ones C and D have more storage capacity for energy than smaller ones. Voltage is another feature to measure a battery. Higher the voltage, the more electricity it will produce when connected to a given circuit.

FAQ (Frequently Asked Questions)

1. What is an electron?

There are different ideas about electrons. The most common one is, an electron is a part of an atom. There can be 1 to 103 electrons in an atom, depending on the type of it. Electron are very tiny particle, and the mass of each electron is just about 1/1836 mass of hydrogen atom. A hydrogen atom consists of one electron and one proton; therefore, the size of an electron is 1/1836 of that of a proton. Electron is a negative (-ve) charged particle.

2. What is an ion?

An ion is a charged atom or molecule. It becomes charged as the number of protons and electrons are not equal in an atom or molecule. If the number of electrons are more in an atom, it acquires –ve (ANION) charge, and if the number of electrons are less than of proton, then the atom is +ve charged(ION).

3. How electrons flow?

The flow of electrons is synonymous with an electric current. There are two kinds of current Direct current (DC), and Alternate current (AC). When electrons flow in a single direction, such as in batteries or solar cells, direct (DC) current is derived. When electrons flow from positive to negative terminal, as well as from negative to positive terminal, ultimately alternating between those two, AC current is obtained.

You may think electron travel freely in the wire from one end to another just as a car speeding through a highway. But in reality, the mechanism is a bit different. Any conductor through which electricity passes is consists of atoms. Every atom has one or many electrons. If a new electron is placed in the conductor, it will join an atom. The atom will emit another electron to the subsequent atom. This process continues to the farthest point.

4. What does voltage mean in battery?

The term voltage in context to battery means the difference in electric potential between the negative and positive terminal. The more is the difference, the higher is the voltage. Electrical potential refers to the difference in charge between two terminals of the battery.

5. What is voltmeter?

A voltmeter is a device to calculate the electrical potential difference between two points in an electrical circuit. A pointer incorporated in the voltmeter moves across the scale to exhibit the difference. Modern digital voltmeter gives a numerical display on the LCD screen.