Introduction – Natural Phenomena Natural Phenomena are the events or occurrences that happen in nature without human control. Some of them are beautiful and helpful (like rainbows), while others can be dangerous or harmful (like earthquakes, lightning, or cyclones). Electric Charges Every object is made up of tiny particles called atoms. -Atoms contain electrons (–ve), protons (+ve), and neutrons (neutral). -When an object loses or gains electrons, it becomes electrically charged. *Type of Charges *Methods of Charging There are two main methods by which objects can be charged: 1. Charging by Friction (Rubbing) Friction (Rubbing) causes electrons to transfer from one substance to another. One becomes positively charged, while the other becomes negatively charged. –Example: Use a plastic scale or balloon on dry hair: -Real-life examples: 2. Charging by Induction (Without Touching) Charging a neutral object without touching it by simply bringing a charged object close to it. The charged body’s electric field causes the charges inside the neutral object to rearrange themselves. -Example: Bring a negatively charged rod near to a neutral metal ball. 3. Charging by Conduction (Touching) When a charged object touches a neutral object, charges are directly transferred by contact. In conduction, the neutral object always gets the same charge as the charged object. Example: If you touch a negatively charged balloon to a metal can, the can rolls due to gained electrons. *Electroscope An electroscope is a simple device used to detect the presence of electric charge on an object. It helps us find out whether a body is charged or uncharged, and if charged, it can show the nature (type) of the charge. -PARTS: -Working of an Electroscope: -Uses of an Electroscope: 1. Detecting Electric Charge: 2. Testing Conductors and Insulators: Lightning Lightning is a bright flash of light in the sky that occurs during a thunderstorm.It is caused by the discharge of electric charges between clouds or between a cloud and the Earth. *How is Lightning Produced? *Benjamin Franklin’s Experiment *Safety Measures During Lightning –Lightning Conductors A lightning conductor is a metal rod fixed to tall buildings or structures to protect them from lightning strikes. Benjamin Franklin (in 1752) after his famous kite experiment EARTHQUAKE An earthquake is a sudden shaking of the Earth’s surface caused by the release of energy stored in the earth’s crust.This energy is released as seismic waves that travel through the Earth.Earthquakes can range from minor tremors (not felt) to huge destructive quakes. Earthquake is measured by- Richter Scale. It Measures the magnitude (strength) of an earthquake. –Focus (Hypocenter): The point inside Earth where the earthquake starts –Epicenter: The point on Earth’s surface directly above the focus. –Seismic Waves: Waves of energy that travel through the Earth, causing ground shaking. *Causes of Earthquakes 1.Natural Causes -Tectonic Plate Movement -Volcanic Activity -Landslides & Rockfalls 2.Human-Induced Causes –Mining Activities –Reservoir-Induced Earthquakes -Nuclear Explosions * Types of Seismic Waves 1. Primary (P) Waves 2. Secondary (S) Waves 3. Surface Waves * Safety Measures During Earthquake – Indoor Measures: – Outdoor Measures:
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