Science Gr 9

What is the density of water?

1 g/cm³ (gram per cubic centimeter)

What defines matter?

Matter is anything that has mass and occupies space.

What are subatomic particles?

Subatomic particles are the particles that make up atoms, including protons, neutrons, and electrons.

What are the changes of state between solid, liquid, and gas?

The changes of state include melting, freezing, condensation, evaporation, and sublimation.

What is a physical change? Give an example.

A physical change is a change that alters a substance's appearance but not its composition; an example is ice melting into water.

What is a chemical change? Give an example.

A chemical change results in the formation of new substances; an example is rust forming on iron.

Define ductility.

Ductility is the ability of a metal to be drawn out into a wire.

Define malleability.

Malleability is the ability of a substance to be hammered or pressed into shape without breaking.

What are alkali metals?

Alkali metals are group 1 elements on the periodic table, known for their high reactivity, such as lithium, sodium, and potassium.

What is a cation?

A cation is a positively charged ion.

What is an anion?

An anion is a negatively charged ion.

What defines an isotope?

An isotope is an atom of the same element with a different number of neutrons.

How is the atomic number defined?

The atomic number is the number of protons in an atom's nucleus.

What does the Bohr-Rutherford diagram represent?

The Bohr-Rutherford diagram represents the arrangement of electrons around the nucleus and helps illustrate the atom's structure.

What is the Octet Rule?

The Octet Rule states that atoms tend to gain, lose, or share electrons to achieve a full valence shell of eight electrons.

What is the most abundant gas on Earth and its percentage?

Nitrogen, making up about 78% of the Earth's atmosphere.

Define biotic factors.

Biotic factors are living components of an ecosystem, such as plants, animals, and bacteria.

Define abiotic factors.

Abiotic factors are the non-living physical and chemical elements in the ecosystem, such as water, sunlight, and temperature.

What is the difference between a food chain and a food web?

A food chain is a linear sequence of organisms where each is eaten by the next, while a food web is a complex network of interconnected food chains.

What is meant by a 'producer' in an ecosystem?

Producers are organisms that can make their own food, typically through photosynthesis, like plants.

What does the 10% Rule refer to in ecology?

The 10% Rule states that only about 10% of the energy from one trophic level is passed on to the next level.

What is the carbon cycle?

The carbon cycle describes the process of carbon exchange among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere.

Define deforestation.

Deforestation is the clearing or thinning of forests by humans, which can lead to habitat destruction and climate change.

What is fragmentation in ecology?

Fragmentation is the process where large habitats are divided into smaller, isolated patches, often causing negative effects on species.

What is bioaccumulation?

Bioaccumulation is the process where organisms accumulate toxic substances in their bodies over time, often through the food chain.

What are renewable energy sources?

Renewable energy sources are naturally replenishing, such as solar, wind, and hydroelectric energy.

What are non-renewable energy sources?

Non-renewable energy sources are those that cannot be replenished in a short period of time, such as fossil fuels.

What is static electricity?

Static electricity is the build-up of electric charge on the surface of objects, often caused by friction.

What does a conductor do?

A conductor allows the flow of electrical current, such as copper wire.

What is a series circuit?

A series circuit is a type of electrical circuit where components are connected end-to-end, resulting in a single pathway for current.

What is the importance of voltage in a circuit?

Voltage is the electrical potential difference that drives current through a circuit.

What is the difference between a fuse and a circuit breaker?

A fuse melts to break the circuit when overloaded, while a circuit breaker can be reset after tripping.

Define potential difference.

Potential difference is the difference in electric potential between two points in a circuit, measured in volts.

What is energy efficiency?

Energy efficiency is the ratio of useful energy output to the total energy input, often expressed as a percentage.