Introduction to science Section 1—The Nature of Science Section 2—The Way Science Works Section 3—Organizing Data

The Nature of Science How science takes place A scientist may perform experiments to find a new aspect of the natural world, to explain a known phenomenon, to check the results of other experiments, or to test the predictions of current theories.

Scientist answer questions by investigating They answer these questions by asking them Scientist plan experiments They write their plan and write down equipment needed and make a table to record observations Scientist observe Sometimes observations are not what was expected Scientists always confirm results Repeat experiment to be sure of the observations, think of new questions and experiment again

Science is observing, studying, and experimenting to find the nature of things. Natural Science tries to understand how nature or the whole universe work Most of the time, natural science is divided into biological science, physical science, and Earth science. Look at the chart on page 7 in your text book with the breakdown.

The branches of science work together The different branches of science are mixed and cross over other branches In physical science there are two branches: chemistry and physics and both are dependent on math Science and technology work together Technology is the application of science for practical purposes.

Scientific Laws and Theories Theories explain why something happens and laws describe how something works Experimental results support laws and theories A scientific law describes a process in nature that can be tested by repeated experiments so by definition a “law” is a descriptive statement or equation that reliably predicts events under certain conditions.

An explanation of how a natural process works must be provided by a scientific theory so by definition a theory is a system of ideas that explains many related observations and is supported by a larger body of evidence acquired through scientific investigation. Scientific theories are always being questioned and examined

To be valid a theory must continue to pass several tests: A theory must explain observations clearly and consistently Experiments that illustrate the theory must be repeatable You must be able to predict results from the theory.

Mathematics can describe physical events See book equations on page 10 Theories and laws are always being tested and sometimes they are changed or replaced when new discoveries are made Models can represent physical events they are used when things are too small, too big, or too complex to study easily We use models in our everyday lives example would be a computer model used by meteorologist.

Chapter1—Section 2 The Way Science Works The skills we think are important , however change over time as society and technology change. Science Skills: Identifying problems, planning experiments , recording observations, and correctly reporting data are some if the most important science skills. The most important skill is learning to think creatively and critically.

Critical thinking helps you solve problems logically Critical thinking is the ability and willingness to assess claims critically and to make judgments on the basis of objective and supportive reasons Scientist use scientific method to solve problems Scientific Method is a series of steps followed to solve problems including collecting data, formulating a hypothesis, testing the hypothesis, and stating conclusions

Scientist test hypotheses by doing a controlled experiment In a controlled experiment, variables can affect the outcome of the experiment are kept constant or controlled, except the one that you want to measure Variable: a factor that changes in an experiment in order to test the hypothesis Important: The more things you change at a time, the harder it will be to make reliable conclusions

Experiments test ideas: So even if the desired results are not obtained it is not a failure! You would revise your hypothesis and plan to test a different variable Scientist keep in mind the question being tested They must search for bias in the way they plan and analyze their experiments Published results are examined by other scientist and are then said to have been peer reviewed Some things can not be tested with an experiment, conclusions are formed from collected data

Scientist use special tools: Besides logically thinking scientist use tools made through advanced technology. Examples: telescopes, radio telescopes, spectroscopes, particle accelerators.

Units of Measurement Mathematics is the language of science, and mathematical models rely on accuracy Scientist use the standard units of measure that together for the International Systems of Units, or SI This allows scientist around the world to compare observations and calculations

SI units of measure are used for consistency Notice that base units do not include area, volume, pressure, speed, and other familiar quantities Combinations of these base units are called derived units and are used for these measurements Area of rectangle A= l x w Calculated A =8.0m x 6.0m =48m2 The SI unit for area is, m2

SI prefixes are used for the very large and very small measurements You can convert between smaller and larger numbers Look at the practice problems on page 19 and solve them following the sample problem

Measurements quantify your observation Many observations rely on quantitative measurements. Basic scientific measurements usually answer questions such as “How much time did it take” Length—a measure of the straight-line distance between 2 points Mass—a measure of the amount of matter in an object Volume—a measure of the size of a body or region in three-dimensional space Weight—a measure of the gravitational force extended on an object

Finally: weight is not the same as mass! Mass is the quantity of matter, and weight is the force with which Earth’s gravity pulls on that quantity of matter.

Section 3: Organizing Data Presenting Specific Data Scientist use written reports and oral presentations to share their results, organizing and presenting data are important science skills Line graphs show continuous changes Line graphs are good choices for displaying changes continuously With 2 variables you place the independent on the x-axis and the dependent on the y-axis (see pg 23in text)

Bar graphs compare the values of items Bar graphs are useful when you want to compare similar data for several individual items It is a better choice than a line graph for showing single values for many items Pie graphs show parts of a whole

Writing numbers in Scientific Notation This helps to reduce the number of zeros in very big and very small numbers, you can express the values as simple numbers multiplied by a power of 10, a method called scientific notation See text pg 24 Use scientific notation to make calculations Using Significant figures Scientist use significant figures to show precision of a measured quantity

Accuracy differs from precision Precision—the exactness of a measurement Accuracy—description of how close a measurement is to the true value of the quality measured See fig 5 in text book on pg 27 Significant figures When measuring calculations , the answer is only a precise as the least precise measurement used in calculation—the measurement with the fewest significant figures

Significant figure—a prescribed decimal place that determines the amount of rounding off to be done based on the precision of the measurement.