Introduction to Science Chapter 1 Introduction to Science

Physical Science What causes thunderstorms? What kinds of creatures live at different depths in the ocean? What clues to the earth’s past are found in its rocks? What makes a rocket move? How do lasers and computers work? What is sound? What are atoms made of?

Physical Science All these questions are under the domain of physical science… Physical science is the systematic study of God’s physical creation and how it works.

Mathematics: The Language of Science Scientists use mathematics to describe the physical universe. Physical Science is inseparable from mathematics.

Descriptions Mathematical descriptions are more precise than nonmathematical descriptions. Qualitative Descriptions (like “the sun is hot.” and “the rock is heavy.”) are true, but do not give and accurate description. Quantitative Descriptions (like “the sun has a surface temperature of 11,000 °F”) is a more accurate description.

Equations Scientist express the laws of the universe as mathematical equations. Equations can be simple… Volume of a box: V = lwh Equations can be complex: Equation of gravity:

Equations Remember: Equations should be memorized according to the actual relationships they represent… s = d/t should be memorized as speed equals distance divided by time.

Limitations of Mathematics The scope of mathematics is limited to that which can be measured and expressed numerically. Human nature, for example, cannot be expressed by equations. Right and wrong cannot be determined by mathematics. The existence of God cannot be determined by mathematics.

Truth and Error Mathematics can be used for truth or error. The scientist is only human…he can make errors in calculations. He can also make errors because of false assumptions made by a scientist who is attempting to solve a problem.

Limitations in Measurements There are two types of certainty (or uncertainty) in scientific measurement: The accuracy – exactness The precision – repeatability Measurements must be consistent in order to be precise.

Significant Figures Measurements are recorded to the first uncertain digit. For example: 110.5 lb from a bathroom scale has uncertainty with the last digit…the first three are significant. When averaging measurements, the resultant may only have as many significant digits as the original measurements.

Scientific Notation A “short cut” for long numbers: Scientists deal with LARGE numbers… The nearest galaxy is 19,000,000,000,000,000,000 kilometers away from earth… It can be written as a multiple of 10… 19 X 1019 kilometers

Systems of Measurement A standard of measurement: A specific measure to which other measures are compared to ensure uniformity. The F.P.S. (foot-pound-second) system is used in the United States.

Systems of Measurements The metric system: Developed in the 1790’s by the French. It is based on the powers of 10.

Basic Metric Units and Prefixes The basic units are: Length – meter (m) Volume – liter (L) Mass – gram (g) Prefixes are attached to make the basic unit larger or smaller. Common prefixes are milli – 10-3 centi – 10-2 kilo – 103

Definitions of SI Units Length: Meter - the distance light travels in exactly 1/299,792,458 of a scond Centimeter – 1/100 of a meter Millimeter – 1/1000 of a meter Kilometer – 1000 meters

Definitions of SI Units Volume: Liter – 1000 cubic centimeters milliliter – 1/1000 liter Mass: Defined as the amount of matter in an object Differs from weight which is the pull of gravity on a mass Unit is gram Kilogram – 1000 grams

Definitions of SI Units Time: Unit is second Temperature: Unit is Celsius Conversions: Fahrenheit to Celsius: °C = 5/9(°F-32) Celsius to Fahrenheit: °F = 9/5 °C+32

Definitions of SI Units The Kelvin temperature scale: The coldest possible temperature is called absolute zero (equal to -273 °C) This is the temperature at which molecules cease to vibrate Absolute zero is a theoretical value and cannot actually be reached as matter is always in motion. Conversions for Kelvin: Celsius to Kelvin: K=°C+273 Kelvin to Celsius: °C = K-273

The Scientific Method There are three basic steps: 1. observing – gathering facts 2. hypothesizing – suggesting explanations 3. experimenting – testing explanations

Theories and Laws When a hypothesis passes the test of many experiments and has the support of other scientists, it is referred to as a Theory. If the theory is verified by enough observations and stands the test of time it becomes accepted as a Scientific Law.

Predictions Scientists use hypothesis and equations to make predictions that they then test. Predictions must be testable, like Galileo’s gravity predictions.

Assumptions All scientific predictions are based on assumptions that may prove true or false. For example: One of the most basic of all scientific assumptions is that the universe is lawful, orderly, and operates according to physical laws. This assumption is sometimes referred to as causality, or the law of cause and effect. By discovering what causes produce what effects, we can understand how the universe works.