Science Concepts: Physical & Chemical Properties, Measurement

Science Concepts: Physical and Chemical Sciences

SCIENCE is a wealth of knowledge about the world obtained through observation, experimentation, and reasoning. Laws are deduced from verifiable theories that are elaborated from these processes.

Physical and Chemical Sciences

PHYSICAL-q is the science that studies any change that does not alter the material nature of matter. QUIMICA-is is the science that studies the composition, combinations, and transformations of substances that affect their nature.

General Properties

General Properties are values that serve to identify a substance; for example, volume and temperature are properties used to describe matter.

Property Features

THE PROPERTY FEATURES are the characteristic values for each substance. Examples include:

• Density — a measure of mass per unit volume (mass/volume).
• Unit — point; lead (original fragment: "FUCI. el punt of hustle") — retained as in the original text.
• Hardness — the durability of a material; the resistance shown to being scratched (e.g., diamond).
• Water solubility — the mass of a substance that can dissolve in 100 g of water (e.g., sugar).
• Electrical conductivity — measures a substance's ability to transmit an electric current (e.g., metals).

Magnitude and Measurement

MAGNITUDE-characterizes matter and any changes it may experience which can be measured; that is, any feature that can be expressed by a number and a unit.

Measurement — measuring a magnitude consists of comparing it to a quantity (a unit) so that the property can be expressed numerically. Measurements allow us to quantify natural properties and track changes over time.

Conversion Factor

Conversion factor — a fraction where the numerator and denominator represent the same quantity (magnitude) but expressed in different units. Conversion factors are used to change units while keeping the same physical quantity.

Scientific Method

Scientific method — the procedure followed by people who work in science to study problems and reach reliable conclusions. The typical steps are:

1. Observation — examine and analyze a phenomenon; plan specific questions about the phenomenon.
2. Developing a hypothesis — propose a possible explanation for the phenomenon and answer the planned questions. Each possible answer is a hypothesis.
3. Experimentation — reproduce the observed phenomena under controlled conditions to verify whether the hypotheses are true.
4. Analysis of results — calculate, manage, and analyze experimental data (now often aided by computers) and data tables.
5. Obtaining conclusions — draw conclusions; in many cases these conclusions allow predictions of future observable phenomena.
6. Publication of results — the objective is that other scientists can reproduce or use the results in their own studies.