Science Review

Chemical changes result in the formation of new substances. Fireworks, baking a cake, and digesting food all involve chemical reactions that create new chemical products.

Physical changes do not change the chemical identity of the substance. Cutting vegetables, mowing the lawn, and freezing water are all physical changes because the material remains the same.

According to the law of conservation of mass, the mass of a substance remains constant during a phase change. Freezing water does not change the amount of matter present.

Chemical reactions are characterized by observable changes such as color changes, light emission, or energy release. Fireworks exhibit these traits as the chemicals react.

Mass is conserved in a mixture. Adding 5 grams of mix to 100 grams of water results in a total mass of 105 grams.

The total mass of an object is equal to the sum of the masses of its parts. Taking the house apart does not change the total mass of the individual blocks.

Erosion is a surface process caused by wind, water, or ice moving sediment. Earthquakes, volcanoes, and uplift are all driven by tectonic plate movements.

According to the principle of superposition in geology, in an undisturbed sequence of sedimentary rocks, the oldest layers are at the bottom and the youngest are at the top.

Natural arches in places like Southern Utah are primarily formed by the erosion of rock over long periods, largely due to the action of water and wind.

A butte is an isolated hill with steep sides and a flat top, commonly found in the American Southwest.

Weathering is the process of breaking down rocks, soil, and minerals in place. Erosion is the process of moving that material away.

When tectonic plates move against each other, the stress built up at the boundaries is released as seismic waves. This release of energy results in an earthquake.

Opposite magnetic poles, specifically the north and south poles, exert an attractive force on each other. Like poles, such as north-north or south-south, would repel.

A compass needle is a small magnet that aligns with the Earth's magnetic field. It points toward magnetic north, not south.

All magnets have two poles, a north pole and a south pole, where the magnetic force is strongest. Even if you cut a magnet in half, each piece will still have a north and south pole.

The Earth acts like a giant bar magnet because of the movement of molten iron in its outer core, which creates a magnetic field with north and south poles.

Nickel, iron, and cobalt are all ferromagnetic materials. This means they are all strongly attracted to magnets.

In electromagnetism, like charges (positive-positive or negative-negative) exert a repulsive force on each other. Opposite charges attract.

Current electricity refers to the flow of electric charge through a conductor, which is the steady form of electricity used to power household appliances.

An open circuit is one where the path for electricity is broken, preventing the flow of current. A closed circuit provides a continuous path for current to flow.

A conductor is a material that allows electric current to flow through it easily because its electrons are loosely bound and free to move. Metals like copper are common conductors.

An insulator is a material that resists the flow of electricity because its electrons are tightly bound to their atoms. Examples include rubber, plastic, and glass.

For current to flow, there must be a complete, unbroken path from the power source through the load and back. This is known as a closed circuit.

Static electricity is the accumulation of electric charge on the surface of an object, often caused by friction, which remains stationary until it is discharged.

A specialized structure is a physical trait that has evolved to help an organism survive. A baby's breathing is a basic physiological process, not a specialized structural adaptation.

Teeth for chewing plants are a general characteristic of herbivores, not a specific adaptation for protection against predators. Speed, eyesight, and hearing are all direct defensive adaptations.

Variations in traits allow some individuals to be better suited to their environment than others. This is the basis of natural selection and survival.

Inherited traits are passed down through genes from parents. Being physically fit is a result of lifestyle, exercise, and diet, not genetic inheritance.

Heredity is the biological process by which genetic traits are passed from parents to their offspring.

In sexual reproduction, offspring inherit half of their genetic material from their mother and half from their father.