Study Sheet_ Systems in Action - Investigating Science and Technology 8

Study Sheet: Systems in Action - Investigating Science and Technology 8

1. Definitions

• Basic Terms

  • System: A group of parts working together to perform a function.

    • Purpose: The main goal or function of the system, like lifting, transporting, or powering something.

    • Inputs: Energy, materials, or information that enter the system. (e.g., fuel, electricity, raw materials)

    • Outputs: The result or product of the system’s function. (e.g., motion, light, heat, waste)

  • Input: Energy, materials, or information entering a system.

  • Process: The transformation of inputs to produce an output.

  • Output: The result or product of the system’s function.

  • Feedback: A loop within a system that adjusts performance based on the output.

  • Efficiency: Measures how well a system converts input energy into useful output energy.

Energy & Work

• Energy: The capacity to do work, measured in joules (J).

• Work: The application of force over a distance.

• Power: The rate at which work is done.

• Force: A push or pull acting on an object, measured in newtons (N).

• Displacement: The movement from one point to another.

Types of Energy

1. Kinetic Energy: Energy of motion.

2. Potential Energy: Stored energy due to position.

3. Chemical Energy: Stored in chemical bonds (e.g., food, fuel, batteries).

4. Electrical Energy: Energy from moving electrons (e.g., power lines, batteries).

5. Thermal Energy: Energy from the movement of particles (e.g., boiling water, fire).

6. Mechanical Energy: Total kinetic and potential energy in an object.

7. Nuclear Energy: Stored in the nucleus of an atom (e.g., nuclear power plants).

2. Forces

• Contact Forces: Require physical contact (e.g., applied force, friction, tension).

• Non-Contact Forces: Act at a distance (e.g., gravity, electrostatic force, magnetism).

  • Electrostatic Force: Attraction/repulsion between charged objects.

  • Gravitational Force: Pulls objects toward each other (e.g., Earth’s gravity).

  • Magnetism: Force acting between magnetic materials.

Mass vs. Weight

• Mass: The amount of matter in an object (kg) – does not change with location.

• Weight: The force of gravity acting on an object (N) – changes based on gravity.

  • Formula: Weight = Mass × 9.8 m/s²

3. Formulas

• Work & Energy

  • Work (W) = Force (F) × Distance (d)

  • Power = Work / Time

Mechanical Advantage (MA)

• General Formula: MA = Output Force / Input Force

  • Higher MA = less effort needed.

• Pulleys: MA = Number of Supporting Ropes

• Levers: MA = Input Arm Length / Output Arm Length

Gear Ratios & Mechanical Advantage with Gears

• Gear Ratio: Gear Ratio = Teeth on Output Gear / Teeth on Input Gear

  • If gear ratio > 1, system increases torque but reduces speed.

  • If gear ratio < 1, system increases speed but reduces torque.

4. Important Points

First Law of Energy

• Law of Conservation of Energy: Energy cannot be created or destroyed, only transformed from one form to another.

  • Example: A roller coaster at the top has potential energy, which turns into kinetic energy as it moves down.

How Energy Passes Through Objects

• Conduction: Heat transfer through direct contact (e.g., touching a hot pan).

• Convection: Heat transfer in fluids (e.g., boiling water).

• Radiation: Heat transfer through waves without touching (e.g., the Sun warming the Earth).

Energy in Waves

• Sound Waves: Vibrations in air or other materials.

• Light Waves: Electromagnetic energy traveling through space.

• Water Waves: Transfer energy across water surfaces.

• Seismic Waves: Energy released during earthquakes.

Simple Machines & Applications

• Levers: Reduce force needed by increasing distance (e.g., scissors).

• Inclined Planes: Reduce force over longer distance (e.g., ramps).

• Pulleys: Change force direction, reduce effort (e.g., cranes).

• Wedges: Split objects or hold them together (e.g., knives).

• Screws: Convert rotational force into linear motion (e.g., jar lids).

• Wheel & Axle: Reduce friction, making movement easier (e.g., cars).

• Gears: Transfer motion and force through interlocking teeth.

Scientists to Know

• James Joule (1818-1889): Studied energy and heat, leading to the unit "joule (J)".

• Isaac Newton (1643-1727): Developed laws of motion and gravity.