Science

Physical Change

A change that affects one or more physical properties of a substance without altering its chemical composition.

Chemical Change

A change that occurs when one or more substances are transformed into different substances with different chemical properties.

Synthesis Reaction

A type of reaction where two or more reactants combine to form a single product.

Decomposition Reaction

A reaction where a single reactant breaks down into two or more simpler products.

Endothermic Reaction

A reaction that absorbs energy from its surroundings, typically causing a drop in temperature.

Exothermic Reaction

A reaction that releases energy into its surroundings, usually resulting in an increase in temperature.

Collision Theory

A theory that states reactants must collide in order to react, and the rate of reaction depends on the frequency and energy of collisions.

Catalyst

A substance that increases the rate of a chemical reaction without being consumed in the process.

Law of Conservation of Mass

The principle stating that mass is neither created nor destroyed during a chemical reaction.

Element

A pure substance that cannot be broken down into simpler substances by chemical means.

Compound

A substance made of two or more different elements that are chemically bonded together.

Mixture

A combination of two or more substances where each retains its own properties and can be separated by physical means.

Atom

The smallest unit of a chemical element that retains its chemical properties.

Molecule

A group of two or more atoms bonded together, forming the smallest unit of a substance.

Proton

A positively charged subatomic particle found in the nucleus of an atom.

Neutron

A neutrally charged subatomic particle found in the nucleus of an atom.

Electron

A negatively charged subatomic particle that orbits the nucleus of an atom.

Periodic Table

A chart that organizes elements by increasing atomic number and groups elements with similar properties.

Valence Electrons

Electrons in the outermost shell of an atom that determine its chemical properties and reactivity.

Cerebrum

The largest part of the brain, responsible for higher brain functions such as thought and action.

Cerebellum

Part of the brain that controls balance, posture, and coordination of movements.

Medulla Oblongata

The part of the brain that controls involuntary actions such as breathing and heartbeat.

Central Nervous System (CNS)

The part of the nervous system consisting of the brain and spinal cord.

Peripheral Nervous System (PNS)

The part of the nervous system that connects the CNS to the rest of the body through nerves.

Sensory Neurons

Neurons that receive and transmit sensory information to the CNS.

Interneurons

Neurons that connect sensory and motor neurons within the CNS.

Motor Neurons

Neurons that carry impulses from the CNS to effectors such as muscles or glands.

Activation Energy

The minimum amount of energy required for a chemical reaction to occur.

Homogeneous Mixture

A mixture that has a uniform composition and appearance throughout.

Heterogeneous Mixture

A mixture that consists of visibly different substances or phases.

Kinetic Energy

The energy that an object possesses due to its motion.

Maxwell-Boltzman Distribution

A statistical distribution of particle speeds in gases that is used to explain reaction rates at different temperatures.

Chemical Formula

A way to represent a substance using symbols for its constituent elements and their ratios.

Mendeleev's Periodic Table

A table arranged by increasing atomic weight and grouped by similar chemical properties, predicting the existence of unknown elements.

Homeostasis

The process by which living organisms regulate their internal environment to maintain stable, constant conditions.

Stimulus-Response Pathway

The process by which organisms respond to environmental changes through detection and reaction.

Reflex Arc

A neural pathway that mediates a reflex action, typically involving sensory and motor neurons without direct involvement of the brain.