Page 16 - Physics_Form_2

Physics for Secondary Schools

it to attract small bits of paper when the materials, leading to static electricity.
brought close. The series is a useful tool for predicting
2. Rubbing a glass rod with silk: When the outcome of charge transfer in various
a glass rod is rubbed with silk, the scenarios.
glass rod loses electrons and becomes
positively charged, while the silk gains Triboelectric series
FOR ONLINE READING ONLY
electrons and becomes negatively
charged. Human skin

3. Wool Sweater and Human Skin: In Rabbit fur
colder months, when you take off a Glass
wool sweater, you may notice sparks
or hear crackling sounds. This is due Human hair
to the static electricity generated as Wool
electrons transfer from the wool to
your skin. Positive Silk
Cotton Negative
The Role of insulators and conductors Wood
Not all materials can be charged by
friction. Only insulating materials can be Amber
effectively charged through this method polystyrene
because their electrons are not free to Ebonite
move. In contrast, conductors allow
electrons to move freely, which means
they cannot hold a static charge. Common Figure 1.11: Triboelectric series
insulating materials include rubber,
glass, and plastic, while metals are good When two materials from this series are
conductors. rubbed together, the one higher in the
series will gain electrons, while the one
Triboelectric series lower will lose electrons. For example, if
The triboelectric series is a ranking of you rub a glass rod with silk, the glass rod
materials based on their propensity to will lose electrons and become positively
gain or lose electrons through contact or charged, while the silk will gain electrons
friction. The position of a material in the and become negatively charged
series indicates whether it will tend to
become positively or negatively charged Charging an object by contact
when rubbed against another material (conduction)
(see Figure 1.11). Materials higher on the Charging by contact is achieved by
list tend to become positive, while those bringing a charged body into contact with
lower become negative. This effect is an uncharged one. Charges are transferred
due to the transfer of electrons between from the charged body to the uncharged

10
Student’s Book Form Two

Physics Form 2 Final.indd 10 25/10/2025 10:25