physical science ch 2, sec 1 tools in science

Section 1 Tools and Models in ScienceChapter 2

Tools in Science

• A tool is anything that helps you do a task.

• Scientists use many different tools to help them make observations, take measurements, and analyze data.

Section 1 Tools and Models in ScienceChapter 2

Making Measurements

• The International System of Units (SI) is the standard system of measurement. All SI units are expressed in multiples of 10.

• Prefixes are used to express SI units that are larger or smaller than basic units. For example, kilo- means 1,000 times, and milli- indicates 1/1,000 times.

Section 1 Tools and Models in ScienceChapter 2

Making Measurements, continued

• Length, mass, volume, density, and temperature are common measurements.

• The meter is the basic SI unit of length.

• The kilogram (kg) is the basic SI unit for mass. Mass is the measure of the amount of matter in an object.

Section 1 Tools and Models in ScienceChapter 2

Making Measurements, continued

• Liquid volume is expressed in liters (L). Volume is a measure of the size of an object in three-dimensional space.

• The volume of solid objects is usually expressed in cubic meters (m3).

Section 1 Tools and Models in ScienceChapter 2

Making Measurements, continued

• Density is the ratio of the mass of a substance to the volume of the substance.

• The temperature of a substance is a measurement of how hot the substance is.

• The kelvin (K) is the SI unit for temperature.

Data in ScienceChapter 2

Section 1 Tools and Models in ScienceChapter 2

Models in Science

• A model is a representation of an object or system. A model uses something familiar to help you understand something that is not familiar.

• Physical, conceptual, and mathematical models are commonly used in science.

• Models have limitations because they are never exactly like the real thing.

Section 1 Tools and Models in ScienceChapter 2

Using Models for Scientific Progress

• In science, a theory is a system of ideas that explains many related observations and is supported by a large body of evidence acquired through scientific investigation.

• In science, a law is a descriptive statement or equation that reliably predicts events under certain conditions.