Page 86 - SCERT Kerala State Syllabus 8th Standard Basic Science Textbooks English Medium Part 1_Neat

LED
decomposition by the absorption of electrical energy
Switch
is known as electrolysis.
Set up the apparatus as shown in Figure 6.6.

Why does the LED glow when the switch is turned
on? How is this form of energy produced?
Here, electricity is produced as a result of a chemical
reaction between the acid and the metals kept
immersed in it. Such arrangements which produce Copper
electricity as a result of chemical reaction are known
Zinc
as Electrochemical cells.
A battery made of lemons Dilute
sulphuric
Take a few lemons and in each one of them, fix a acid
copper rod and a zinc strip. As shown in Figure 6.7, Fig. 6.6
connect the zinc strip of one lemon to the copper rod

Fig. 6.7
of the next lemon. Connect the copper rod on the first lemon
and the zinc strip on the last lemon to an LED using a conducting
wire. The LED glows. What is the reason?
You know that lemon and many other fruits contain acids.
Electricity is produced here by the reaction of these acids with
metals.
Try to make cells using a variety of fruits and different metals.

Chemical reactions in which electrical energy is consumed or
produced are known as electrochemical reactions.
Electroplating

You are familiar with the gold plated ornaments that are
available in the market. Electricity is used to obtain a thin coating
of a particular metal on other metallic objects. This process is

Basic Science VIII 85