Scientific Method and Physical Science Overview

A diagram that illustrates the proportion of parts that make up a whole entity. It's usually in the shape of a circle divided into segments representing each part.

A systematic method of investigating and understanding natural phenomena. It involves steps like observation, hypothesis formation, experimentation, analysis, and conclusion.

Social sciences focus on human behavior and society, while natural sciences study the physical universe. Social sciences use different methods to understand complex human interactions.

Physical science is concerned with the fundamental laws governing matter and energy. It encompasses areas like physics, chemistry, and astronomy.

If your results don't match your hypothesis, it means your initial prediction needs revision. You should analyze the experiment, identify potential errors, and adjust your hypothesis.

Scientific theories are based on extensive evidence and observations, but they are always subject to further refinement or revision as new information emerges. They are not absolute truths.

Scientific models are simplified representations of complex phenomena, processes, or systems. They help us visualize and understand abstract concepts by using physical objects, diagrams, or mathematical equations.

Safe laboratory procedures include wearing appropriate safety gear (like goggles), handling chemicals carefully, following instructions, and knowing where safety equipment (like fire extinguishers) is located.

Scientific notation is a way of expressing very large or very small numbers using powers of ten. It makes it easier to write and manipulate these numbers.

20mm is equal to 2 cm. To convert millimeters to centimeters, you divide the value in millimeters by 10.

42.27 is considered more precise than 42.3 because it includes more decimal places. Precision refers to the level of detail and the number of significant figures.

Milk is a mixture because it contains different substances that are not chemically combined. It's a heterogeneous mixture, meaning its components are not evenly distributed.

A compound is a substance formed when two or more elements chemically combine in a fixed ratio. It has properties different from the original elements.

A mixture is a combination of two or more substances that are not chemically combined. The components can be separated by physical means, and they retain their individual properties.

A pure substance is a substance that has a fixed chemical composition and uniform properties throughout. It cannot be broken down into simpler substances by physical means.

Viscosity is a fluid's resistance to flow. It's a measure of how easily a fluid pours or spreads.

Metals are generally shiny, malleable (can be hammered into shapes), ductile (can be drawn into wires), good conductors of heat and electricity, and have a high density.

Filtration separates components of a mixture by passing it through a porous material like filter paper. Solids get trapped, while the liquid passes through.

A chemical change results in the formation of new substances with different chemical properties. A physical change affects the form or appearance but not the chemical composition.

In solids, atoms are tightly packed and arranged in a regular, repeating pattern. Liquids have less order, with atoms closer together than in gases. Gases have the most freedom of movement, with widely spaced atoms.

Solids have a definite shape and volume. Liquids take the shape of their container but have a fixed volume. Gases take the shape and volume of their container.

Phase changes are transitions between states of matter. Examples include melting, freezing, vaporization, condensation, sublimation, and deposition.

During a phase change, temperature remains constant despite heat being added or removed. The energy is used to break or form bonds between molecules, not to increase temperature.

John Dalton proposed the atomic theory, stating that all matter is made of atoms, which are indivisible and indestructible. He also described the Law of Multiple Proportions.

J.J. Thomson discovered the electron using the cathode ray tube experiment. He proposed the 'plum pudding' model, where electrons were embedded in a positively charged sphere.

Ernest Rutherford conducted the gold foil experiment, which led to the discovery of the nucleus. He determined that the atom has a small, dense, positively charged nucleus surrounded by negatively charged electrons.

Niels Bohr proposed a model of the atom where electrons orbit the nucleus in specific energy levels. He explained the line spectra of atoms.

The three subatomic particles are protons (positive charge, located in the nucleus), neutrons (no charge, located in the nucleus), and electrons (negative charge, orbiting the nucleus).

The Bohr model shows electrons orbiting the nucleus in fixed paths like planets. The Quantum or Cloud model is more accurate, showing electrons as existing in probability clouds around the nucleus.

The atomic mass is the average mass of an element's atoms, usually a decimal number. The mass number is the total number of protons and neutrons in an atom, usually a whole number on the periodic table.

To find the number of neutrons in an atom, subtract the atomic number (number of protons) from the mass number.

Periods are horizontal rows on the periodic table, elements in the same period have the same number of electron shells. Groups are vertical columns, elements in the same group have the same number of valence electrons.

Metals are found on the left and center of the periodic table. Transition Metals are located in the middle block (groups 3-12). Non-metals are on the right side.

The most reactive elements are found in Group 1 (alkali metals) and Group 17 (halogens). These elements readily lose or gain an electron to achieve a stable electron configuration.

The number of valence electrons (electrons in the outermost shell) determines an element's reactivity. Elements with fewer or more valence electrons than a stable configuration (8 for most) tend to be more reactive to gain or lose electrons.

Elements achieve electrical stability by gaining, losing, or sharing electrons to attain a full outer shell (octet rule). This leads to a stable electron configuration, which reduces reactivity.

Ionic bonds form when one atom donates an electron to another atom, resulting in oppositely charged ions that attract each other. Covalent bonds form when atoms share electrons to achieve stability. Ionic bonds typically occur between metals and nonmetals, while covalent bonds usually involve two nonmetals.

H2 (Hydrogen): H-H
O2 (Oxygen): O=O
N2 (Nitrogen): N≡N

Ionic compounds are named by writing the cation's name followed by the anion's name, with the anion ending in 'ide'. For example, NaCl is Sodium Chloride.

In a chemical equation, the reactants (starting materials) are on the left side, and the products (what's formed) are on the right side, separated by an arrow indicating the direction of the reaction.

Balancing a chemical equation involves adjusting coefficients in front of each chemical formula to ensure the same number of atoms of each element on both sides of the equation, maintaining the Law of Conservation of Mass.