Take a battery, few wire pieces, a bulb, a nail and a pencil lead. First connect the nail in the circuit as shown in the figure. Is the bulb glowing? Now, connect the pencil lead in the circuit. What do you observe?
The bulb glows when the
nail is connected because metal transfers energy, while the graphite lead
produces heat energy.
Strike a metal utensil with a metal spoon. Note the kind of sound emitted. Now, strike a piece of wood charcoal with the same spoon. Do you find difference in the kind of sound produced? Most metals produce ringing sound when struck i.e. they are sonorous. Non-metals are non sonorous.