Grade 6 Science Semester 1: Metals, Non-Metals, and Energy Practice Sheet

Definition of Metals: Metals are a category of elements characterized by specific physical properties, typically being strong, durable, and functional in industrial applications.
Common Physical Properties:
- Lustrous: Metals are generally shiny in appearance.
- Conductivity: They are excellent conductors of both heat and electricity.
- Malleability: This is the ability of a metal to be hammered or pressed into different shapes without breaking.
- Ductility: This refers to the ability of a metal to be stretched into long, thin wires. Copper is a primary example used for this purpose.
- Sonority: Metals are described as sonorous because they produce a distinct ringing sound when struck.
- Strength and Hardness: Most metals are strong and hard, which makes them ideal for structural uses.
Specific Examples and State of Matter:
- Mercury: This is a unique metal because it is liquid at room temperature. It is commonly used in thermometers and fluorescent lamps.
- Iron: Known for being strong and hard, iron is frequently used in the construction of massive structures like bridges.
- Copper: Preferred for making long electrical wires due to being an excellent conductor of electricity, its high ductility, and its resistance to corrosion.

General Physical Properties:
- Appearance: Non-metals are typically dull and not shiny.
- Conductivity: They are generally poor conductors of both heat and electricity.
- State and Texture: If solid, non-metals are usually brittle, meaning they break or shatter easily when stressed rather than deforming.
Key Example - Carbon:
- Diamond: A very hard form of the non-metal carbon.
- Graphite/General Carbon: Properties allow it to be used in the production of pencils and electrodes.

Definition: An alloy is a mixture consisting of two or more metals, or a metal and another element.
Advantages of Alloys: Alloys are generally preferred over pure metals for several reasons:
- They are stronger than pure metals.
- They are more resistant to corrosion (e.g., rusting).
- They possess improved properties tailored for specific industrial or commercial uses.
Specific Alloy Examples:
- Brass: An alloy made from the combination of $Copper + Zinc$ . It is used for manufacturing musical instruments and water taps.
- Steel: An alloy frequently used in heavy construction, including bridges and the manufacturing of cars.

Definition of Energy: The ability to do work or perform tasks. The $SI$ unit of energy is the $Joule$ .
Forms of Energy:
- Kinetic Energy: The energy possessed by objects that are in motion.
- Gravitational Potential Energy: The energy stored in objects due to their height or position above the ground.
- Elastic Energy: Energy stored in objects that have been stretched or compressed.
- Chemical Energy: Energy stored within the bonds of fuels and food substances.
- Thermal Energy: The energy associated with hot objects.
- Electrical Energy: Energy that is transferred through an electric current.
- Light Energy: The form of energy that is visible to the human eye.
- Sound Energy: The energy produced by vibrating objects that can be detected by the ear.

Conservation of Energy: Energy is never truly lost or destroyed; it is only converted or transformed from one form to another.
Useful vs. Wasted Energy:
- Useful Energy: The specific form of energy output that performs the desired task or job. For example, in a light bulb, the light produced is the useful energy output.
- Wasted Energy: Energy that is converted into a form that is not intended for the task. It often spreads out or dissipates into the surroundings. In most electrical appliances, the primary form of wasted energy is Heat (Thermal) energy.
Dissipation: The process where unwanted or wasted energy spreads out into the environment, making it less useful.
Corrosion: A process such as rusting that affects metals like iron and steel, often leading to the degradation of the material.

Cooking Utensils: Metals are used to manufacture cooking pots because they are good conductors of heat, as well as being strong, durable, and malleable.
Battery-Powered Handheld Fan: This device demonstrates multiple energy changes:
- Source: Chemical energy is stored in the battery.
- Active Energy: The spinning fan possesses Kinetic energy.
- Useful Outputs: The air movement (Kinetic energy) and the humming sound (Sound energy).
- Wasted Output: Heat energy (Thermal energy) generated by the motor.
Dropped Ball Dynamics: When a ball is dropped, the energy transitions through the following sequence:
1. Gravitational Potential Energy: Stored while the ball is held at height.
2. Kinetic Energy: While the ball is falling.
3. Sound Energy + Heat Energy: Produced at the moment the ball impacts the ground.