Introduction to science Chapter 1

1.1 The nature of science

The Nature of Science How does science take place? Scientists investigate Scientists plan experiments Scientists observe Scientists always test results Science has many branches Science and technology work together

What is Science? Science is the process that uses observation and investigation to gain knowledge about events in nature Science has many branches Biological Physical Science Earth Sciences

Branches of Science

Biological Science Biological Science – science of living things Also called Life Science or Biology Botany- science of plants Zoology- science of animals Ecology- science of balance in nature Medicine Agriculture

Physical Sciences Physical Science- science of matter and energy Chemistry- science of matter and its changes Physics- science of forces and energy

Earth Sciences Earth Science- science of Earth Geology- science of the physical nature and history of the Earth Meteorology- science of the atmosphere and weather

Technology- is the application of science Technology and science depend on one another Scientists who do experiments to learn more about the world are practicing pure science

Scientific Law vs. Scientific Theory Scientific Law is a rule of nature that sums up related observations to describe a pattern in nature A law tells us how things work Allows us to make predictions about how a system will behave Does not explain how a process takes place Example: Law of Gravity

Scientific Law vs. Scientific Theory Scientific Theory is an explanation based on experiments most logical explanation They are always being questioned and examined Theories must: Explain observations clearly and consistently Repeatable Predictable Example: Black Hole Theory

Scientific Law vs. Scientific Theory Laws and Theories are always being tested Sometimes theories have been changed or replaced completely when new discoveries are made

Models Scientific model- representation of an object or event that can be studied to understand the real object or event Models represent things that are too small, big or complex to study easily Models can be mental pictures or even mathematical representations.

1.2 The way science works

The Way Science Works Scientists used the scientific method to practice science Scientific method is an organized set of investigation procedures used by scientists

Scientific Method Hypothesis is an educated guess or testable prediction Experiment is an organized procedure for testing the hypothesis Control is the standard for comparison Constant is the factor that does not vary in an experiment

Scientific Method cont. Independent variable is the factor that is adjusted by the experimenter Goes on the x-axis Dependent variable is the factor whose value depends on the independent variable Goes on the y-axis

Scientific Method cont. Share Results Ask a question Conclusion Gather & Analyze Data Further Research Research Form Hypothesis Design Experiment

Units of Measurement International System of Units (SI) Standard system of measurement used worldwide

Units of measurement SI units are used for consistency SI prefixes are for very large and very small measurements Prefix Symbol Meaning Multiplying Factor giga- G billion 1,000,000,000 mega- M million 1,000,000 kilo- K thousand 1000 deci- D tenth 0.1 centi- C hundredth 0.01 milli- thousandth 0.001 micro- μ millionth 0.000001 nano- n billionth 0.000000001

Making Measurements Length – Distance between two points Volume – The amount of space occupied by an object Mass – Amount of matter in an object Density – Mass per unit volume of a material Time – Interval between two occurring events

1.3 Organizing data

Presenting scientific data Graph- a visual display of information or data Types of Graphs: Line Bar Circle or Pie

Line graphs are best for continuous changes Shows trends or how the data changes over time

Bar graphs are best to compare items Bar graphs often make clear how large or small the differences in individual vales are.

Pie charts or circle graphs are ideal for displaying data that are parts of a whole. Usually we use percentages

Writing Numbers in Scientific Notation Scientific notation- a method of expressing a quantity as a number multiplied by 10 to the appropriate power. It is the short hand way to represent where the decimal place is located in a measurement or value.

Positive exponents means to move decimal place to the right Example: 5.4× 10 4 =54,000 Negative exponents means to move decimal place to the left 2.54× 10 −3 =0.00254

Scientific notation rules Adding and Subtracting Powers need to be the same and the answer will have the same power. Example: 4.23× 10 4 +2.22× 10 4 =2.01× 10 4

Scientific notation rules Multiplying and Dividing Powers do not need to be the same Multiplying -> You multiply the base number and add the exponents Dividing -> You divide the base number and subtract the exponents

Multiplication Example 2.23× 10 3 ×4.44× 10 6 = Step 1: Multiply base number 2.23 × 4.44 = 9.9012 Step 2: Add exponents 3 + 6 = 9 Step 3: Put back together 9.9012× 10 9

Divison Example 6.02× 10 6 ÷1.02× 10 3 = Step 1: Divide base number 6.02 ÷1.02 =5.90 Step 2: Subtract exponents 6 −3 =3 Step 3: Put back together 5.90× 10 3

Using Scientific Notation Your state plans to buy a rectangular tract of land measuring 5.36× 10 3 m by 1.38× 10 4 m to establish a nature preserve. What is the area of this tract in square meters?

Precision vs. accuracy Precision means the exactness of a measurement Accuracy a description of how close a measurement is to the true value of the quantity measured