Riya rubs an inflated balloon on her woollen sweater and then brings it near small pieces of paper. She notices that the pieces of paper are attracted towards the balloon. Later, she rubs two balloons on the same sweater and brings them close to each other. This time they repel each other and try to move apart.

After combing his dry hair, Aman brings the plastic comb near tiny bits of paper kept on a table. He observes that the small paper bits jump up and stick to the comb. When he touches the comb with his hand, the paper bits fall down again.

In a school laboratory, a teacher rubs a glass rod with a silk cloth. She then brings the glass rod near a negatively charged plastic rod. The glass rod is observed to be attracted towards the plastic rod. She explains that one of them is positively charged and the other is negatively charged.

On a humid afternoon, dark clouds gather in the sky. The weather department announces the possibility of thunderstorms and lightning. Inside the clouds, air currents move up and down quickly. This movement causes charges to separate within the cloud and between the cloud and the ground.

A simple electroscope is made using a glass jar, a metal wire, and two small aluminium foil strips. The metal wire passes through the lid of the jar. The aluminium strips are attached to the lower end of the wire inside the jar. When a charged glass rod is brought in contact with the upper end of the wire, the aluminium strips move apart.

A charged electroscope has its leaves diverged. A student brings three different objects A, B and C near the top of the electroscope one by one. On bringing object A, the divergence of leaves increases. With object B, the divergence decreases. With object C, there is no change in the divergence of leaves.

A metal rod is connected to an electroscope. When a charged balloon is touched to the free end of the metal rod, the leaves of the electroscope diverge. After some time, the balloon does not attract small paper bits as strongly as before, but the electroscope leaves remain diverged.

A group of children are playing football in an open field. Suddenly, dark clouds appear and thunder is heard. A bright flash of lightning is seen in the sky. Some children continue to play, while others run under a tall, isolated tree in the middle of the ground to take shelter.

During a thunderstorm at night, a family is inside their house. One member is using a wired telephone near the window, another is watching TV with the antenna connected, and a child is standing at the open doorway watching the lightning. Rainwater is also entering through the door.

A new multi-storey school building is being constructed in an area where thunderstorms are frequent. The engineers decide to install a long metal rod along the side of the building, extending above the roof level, with its lower end buried deep in the ground. This arrangement is connected by thick metal strips.

Some villagers are working near a pond when dark clouds appear and lightning starts. One group decides to continue working, standing knee-deep in water. Another group moves away from the pond and sits with their heads down and hands on their knees at a low-lying place away from trees and poles.

A group of students go trekking on a hill. While returning, a thunderstorm starts. Some students rush to stand under a lone tall rock, some hold metal trekking sticks in their hands, while others move down towards a lower region and keep their trekking sticks on the ground away from themselves.

People in a town suddenly feel the ground shaking and see ceiling fans swinging. Some light objects fall down from shelves. Within a few seconds, the shaking stops. Later, the news reports say that this was an earthquake caused by the movement of tectonic plates under the Earth’s crust.

During an earthquake, a village X experiences very strong shaking, while nearby town Y feels mild tremors and city Z, even farther away, barely feels anything. Scientists explain that village X is closest to the epicentre of the earthquake, while Y and Z are progressively farther away.

A geography teacher shows a map of India with different coloured regions indicating low, moderate and high seismic zones. She explains that areas around the Himalayas and parts of north-eastern India are more prone to earthquakes than some central and southern regions. She advises that buildings in high-risk zones should be designed to resist earthquake damage.

After a major earthquake, news reports show collapsed buildings, cracked roads, damaged bridges and fires due to broken gas pipelines. Many people have lost their homes, and essential services like electricity and water supply are disrupted in several areas.

During a science period, students suddenly feel tremors. The teacher quickly instructs them to get under their desks, hold the legs of the desks firmly, and protect their heads with their hands. She asks them to move away from windows and tall cupboards. Once the tremors stop, they carefully move out to an open ground.

Ravi is travelling in a car when he feels strong tremors. The driver stops the car at the side of the road. They notice some tall buildings and electric poles nearby. Ravi suggests that they sit inside the car rather than standing close to the buildings or poles.

Residents of a housing society conduct an earthquake drill. They identify safe places such as strong door frames, under sturdy tables, and open grounds. Emergency kits containing water, food, torch, first-aid box and important phone numbers are prepared. People are trained not to use lifts during an earthquake and to switch off gas and electricity if possible after the tremors stop.

A family plans to build a house in an earthquake-prone area. The architect suggests using light-weight materials for the roof, avoiding very heavy decorative items on walls, and ensuring strong joints between beams and pillars. She also advises keeping the building height moderate and not making very tall, weak structures.