general science reviewer

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Energy

The ability to do work or cause change.

Law of Conservation of Energy

Energy cannot be created or destroyed; it can only be transformed from one form to another. The total energy in a closed system remains constant.

Energy Transformation

The conversion of energy from one form to another.

Mechanical Energy

Energy an object possesses due to its motion (kinetic energy) or its position (potential energy).

Thermal (Heat) Energy

Energy produced by the movement of particles within a substance. The faster the particles move, the more heat is generated.

Electrical Energy

Energy carried by moving electric charges through a conductor.

Chemical Energy

Energy stored within the bonds of atoms and molecules. It is released or absorbed during chemical reactions.

Light (Radiant) Energy

Energy carried by electromagnetic waves. It travels at the speed of light and does not require a medium.

Sound Energy

Energy produced when objects vibrate, creating waves that travel through a medium such as air, water, or solids.

Nuclear Energy

Energy released from the nucleus of atoms through fission or fusion.

Residential Energy Use

Energy used in homes for lighting, cooling, cooking, washing, appliances, and staying connected.

Industrial Energy Use

Energy used to power machines, manufacture products, and run large

Transportation Energy Use

Energy used to move people and goods through cars, motorcycles, buses, trucks, airplanes, ships, and electric vehicles.

Agricultural Energy Use

Energy used for irrigation, farm equipment, harvesting, and crop refrigeration.

Communication Energy Use

Energy used by cell towers, computers, internet infrastructure, television broadcasting, satellite communication, and data centers.

Healthcare Energy Use

Energy used by X

Renewable Energy Sources

Energy sources that are naturally replenished. These clean and sustainable alternatives help reduce pollution and dependence on fossil fuels.

Solar Energy

Harnessing the power of the Sun through solar panels and water heaters to generate clean, sustainable electricity and heat.

Solar Energy Advantages

Clean and renewable; unlimited supply from the Sun; low pollution and minimal greenhouse gas emissions during operation.

Solar Energy Disadvantages

Energy output depends on weather and sunlight availability; high initial installation cost.

Wind Energy

Harnessing the power of moving air to generate clean, renewable electricity through wind turbines.

Wind Energy Advantages

Renewable and inexhaustible; produces no air pollution or greenhouse gas emissions during operation.

Wind Energy Disadvantages

Requires consistently windy areas; can cause noise pollution and may affect local wildlife.

Hydroelectric Energy

Harnessing the power of flowing water to generate clean, reliable electricity for communities and industries.

Hydroelectric Energy Advantages

Reliable and consistent electricity generation; clean energy with no greenhouse gas emissions during operation; long lifespan of facilities.

Hydroelectric Energy Disadvantages

High cost of dam construction and infrastructure; impact on river ecosystems and aquatic life; displacement of communities near reservoir areas.

Geothermal Energy

Heat from Earth’s interior. Philippine examples: Tiwi (Albay), MakBan (Laguna

Biomass Energy

Derived from wood, agricultural waste, and animal waste. It is renewable and can reduce waste, but burning can cause emissions and land use concerns.

Nonrenewable Energy Sources

Finite energy sources formed over millions of years. Once depleted, they cannot be naturally replenished within a human timescale.

Coal

A cheap and reliable energy source used in power plants and industry. It is a major air pollutant and emits CO₂ and greenhouse gases.

Petroleum (Oil)

Used in transportation, plastics, and industrial processes. It causes water and air pollution and has a limited supply.

Natural Gas

A cleaner

Nuclear Fuel

Uranium

Renewable Energy

Naturally replenished; clean and low emissions; sustainable long

Nonrenewable Energy

Finite and depleting; higher pollution and emissions; reliable and consistent; formed over millions of years. Examples include coal, oil, gas, and nuclear fuel.

Energy Efficiency

Using less energy to do the same task.

Energy Conservation

Reducing energy use through behavior.

Sustainability

Meeting needs without depleting future resources.

Importance of Efficient Energy Utilization

Using energy wisely reduces electricity bills, conserves natural resources, minimizes pollution and carbon emissions, improves energy security, and supports sustainable development.

Turn Off & Unplug

Switch off unused lights and appliances. Unplug chargers and devices when not in use to avoid standby power consumption.

Use LED Bulbs & Natural Light

Replace incandescent bulbs with LED bulbs. Use natural lighting and ventilation whenever possible to reduce electricity use.

Walk, Bike & Practice 3Rs

Walk or bike for short distances. Use public transport. Reduce, Reuse, and Recycle to conserve energy and natural resources.

Improper Energy Use

Air and water pollution, climate change, acid rain, habitat loss, and resource depletion.

Proper Energy Use

Cleaner air, sustainable communities, reduced emissions, and biodiversity conservation.

Electricity

The flow of electrons through a conductor.

Electric Current

The movement of charged particles (electrons) through a conductor.

Electrons

Negatively charged particles found in atoms that move through conductive materials.

Electrical Hazards

Situations that can cause injury, death, or property damage.

Electric Shock

Current passing through the body.

Electrical Burns

Burns caused by electrical arcs or contact.

Electrical Fires and Explosions

Fires or explosions caused by sparks or overheating.

Equipment Damage

Damage caused by power surges or short circuits.

Overloading

Too many devices connected to one outlet or extension cord.

Overloading Danger

Excessive current heats the wire, melts insulation, and can cause sparks and fire.

Overloading Safety

Use power strips with breakers, unplug unused devices, and avoid multiple extension cords.

Damaged Insulation

Broken protective covering around electrical wires.

Causes of Damaged Insulation

Aging, heat, rodent bites, sharp objects, and bending.

Damaged Insulation Risks

Exposed wires can cause electric shock, short circuits, and fires.

Damaged Insulation Safety

Replace damaged wires immediately, do not use tape as a permanent fix, inspect regularly, and never pull cords.

Damp Electrical Conditions

Electrical conditions involving water or moisture that increase the risk of shock and short circuits.

Why Water Conducts Electricity

Water conducts electricity due to dissolved ions.

Damp Electrical Conditions Safety

Keep equipment dry, never touch devices with wet hands, dry spills immediately, and keep devices away from sinks.

Faulty Wiring

Damaged or improperly installed wiring.

Causes of Faulty Wiring

Loose connections, old wiring, and poor repairs.

Warning Signs of Faulty Wiring

Flickering lights, warm outlets, burning smell, and sparks.

Faulty Wiring Safety

Have regular inspections, use licensed electricians, replace damaged outlets, and do not overload circuits.

Electrocution

Death caused by electric shock.

Factors Affecting Electrocution

Voltage, current, duration, path, and moisture.

Symptoms of Electrocution

Muscle contractions, burns, and cardiac arrest.

First Aid for Electrocution

Turn off the power first before helping.

Electrocution Safety

Do not touch the victim directly; use a non

Laboratory Electrical Safety

Wear dry gloves, keep liquids away from electrical devices, inspect equipment before use, report damage immediately, turn off equipment after use, and never touch exposed wires.

Fuse

A safety device that melts its wire to stop excess current from flowing.

Circuit Breaker

A safety device that automatically switches off when excess current occurs and can be reset after tripping.

Grounding

Provides a safe path for excess electricity to flow to Earth.

GFCI

A safety device that disconnects power instantly when current leakage is detected; used in wet areas.

Fluid

A substance that can flow, including liquids and gases.

Properties of Fluids

Fluids can flow, exert pressure in all directions, take the shape of their container, and have measurable density.

Density

Mass per unit volume.

Density Formula

ρ = m / V

ρ (Density)

Density measured in kg/m³.

m (Mass)

Mass measured in kg.

V (Volume)

Volume measured in m³.

Pressure

Force per unit area.

Pressure Formula

P = F / A

P (Pressure)

Pressure measured in pascals (Pa).

F (Force)

Force measured in newtons 👎.

A (Area)

Area measured in square meters (m²).

Pascal

A unit of pressure equal to 1 N/m².

Fluid Pressure

Pressure in a fluid given by P = ρgh.

g (Gravity)

Acceleration due to gravity, equal to 9.8 m/s².

h (Depth)

Depth of the fluid measured in meters.

Pascal's Principle

Pressure applied to an enclosed fluid is transmitted equally in all directions.

Pascal's Principle Formula

F₁ / A₁ = F₂ / A₂

Hydraulic Jack

A device that uses a small input force to lift heavy vehicles.

Hydraulic Brakes

Brakes that transmit braking force equally to all wheels.

Hydraulic Press

A machine that uses amplified force to compress or shape materials.

Archimedes' Principle

Buoyant force equals the weight of the fluid displaced.

Buoyant Force

The upward force exerted by a fluid on an object.