Chapter 1 – General Science What is science? How are things studied in science? How are things measured in science?

What is Science? Science – a system of methods used to find knowledge Science begins with curiosity and often ends with discovery Observations can be: Qualitative (descriptive) Quantitative (numerical) Qualitative (how healthy the grass looks, how green it is) Quantitative (number of plants per plot, plant sizes, and growth rates)

Natural Science Physical Science Earth/Space Science Life Science Branches of Science Natural Science Physical Science Earth/Space Science Life Science

Physical Science Focuses on non-living things 2 main areas: Chemistry (study of the composition, structure, properties, and reactions of matter) Physics (study of matter + energy and their interactions through forces and motion)

Earth/Space Science Earth Science – application of physics and chemistry to the study of the Earth Grounded in Geology (study of the origin, history, and structure of Earth) Space Science is about astronomy (study of the universe)

Life Science Also known as Biology (study of living things) Includes: Botany (plants) Zoology (animals) Ecology (interactions with environment) Genetics (DNA)

Some Rules of Nature Matter = made up of atoms 2 characteristics of matter: Mass (amount of matter in an object) Volume (how much space it takes up) Density – relationship b/w mass and volume Mass is the same everywhere in the universe (amount of matter doesn’t change) Weight is dependent on the force of gravity (differs depending on what planet you’re on) Weight on Planets App Floating or sinking of an object does not depend on its weight, it depends upon its density. Things denser than water sink in water whereas things having less mass than water float over it. (Water = 1 g/ml) https://phet.colorado.edu/sims/density-and-buoyancy/density_en.html

Practicing Lab Safety Be responsible in the lab Ask questions Keep hands away from face and mouth Wash hands after experiments Don’t touch anything until instructed Ask questions If you don’t understand directions or procedures Follow instructions carefully Wear protective goggles Use chemicals & glassware properly Never fool around in the lab

Practicing Lab Safety Keep work areas clean Dress properly Long hair tied back No loose or excessively baggy clothing Wear protective clothing, including a lab apron Wear shoes which cover your feet completely (no sandals, flip-flops, or open-toed shoes) No eating in the lab

Scientific Method An organized plan for gathering, organizing, and communicating info Aims to solve a problem

Scientific Method – An Ongoing Process! Scientific investigations begin with observations (info obtained through your senses) Hypothesis – proposed to answer a question (If… then… because) “If _______ (I do this) _________, then _________ (this)_______ will happen, because _____________(this)_________. “If a plant receives fertilizer, then it will grow to be bigger than a plant that does not receive fertilizer because it has more nutrition. Perform experiment to test hypothesis Independent variable – variable that you change in an experiment (“the cause”) Dependent variable – result of the changes made that is measured (“the effect”) A group of college students were given a short course in speed-reading. The instructor was curious if a monetary incentive would influence performance on a reading test taken at the end of the course. Half the students were offered $5 for obtaining a certain level of performance on the test; the other half were not offered money. IV – Monetary incentive ($5 or no money) DV – Performance on reading test Experimental group - $5 group (receive monetary incentive) Control group - $0 (no monetary incentive)

Theory vs. Law Theory – well-tested explanation for a set of observations Never proven, but become stronger if facts continue to support them Theories explain things Law – statement of fact, generally accepted to be true and universal Describes observations without explaining them Theory of evolution – how things came to be Law of gravity – if I drop something, it falls to the ground

Scientific Models A representation that makes things which are difficult to observe directly easier to understand Ex. Model of a cell, map of the US, a globe

Scientific Notation A shortcut in expressing a value as the product of a number between 1-10 and a power of 10 300,000,000 or 3.0 x 108 0.00086 or 8.6 x 10-4 Scientific notation makes a large number or very small number easier to work with Move decimal left = positive Move decimal right = negative

SI Units of Measurement Scientists use a set of international units (SI) when measuring things Length (straight line b/w 2 points) Mass (quantity of matter) Volume (amt. of space taken up by an object) Systeme international d’unites Length – meters (centimeters, millimeters) Mass – grams (kilograms) Volume – liters (milliliters) Temp – Celsius (Kelvin) Time – seconds

Limits of Measurement Precision – how close the measured values are to each other Accuracy – how close a measured value is to the actual (true) value

Scientists organize their data through tables and graphs