NATURE OF SCIENCE

LAB SAFETY Video

SCIENTIFIC PROCESS Make observations and pose a question Perform background research and find out what others have done Form a hypothesis Educated guess based upon observation Rational explanation of a single event Based on what is observed but has not been proved Example: Origin of Life Hypotheses Design and perform an experiment Collect and analyze data Reach a conclusion Communicate results with other scientists

SCIENTIFIC THEORIES Well-supported explanation of a group of observations Based on proven hypotheses; verified multiple times Examples include: Natural selection Cell theory Germ theory

THEORIES VS. LAWS Theories Accepted to be true by scientific community Complex and dynamic Describes an entire group of related phenomena Supported by a large body of evidence Laws Accepted to be true by scientific community Simpler than a theory Describes a single action Examples: Law of gravity Laws of thermodynamics Boyle’s gas laws

SCIENTIFIC ARGUMENT The strength or usefulness of a scientific claim is evaluated through scientific argumentation, which depends on critical and logical thinking The active consideration of alternative SCIENTIFIC explanations based on data collected is also important. Scientific ideas are based on data collected; Religion is base on faith. Argumentation makes scientific ideas stronger and more durable because they must stand up to frequent examination.

RELIABLE SOURCES Scientific journals.edu,.gov,.org Not.coms Expert opinions (someone whose knowledge is supported by their education)

OBSERVATIONS VS. INFERENCES Observations Information that comes to you through your senses Example:Archeologists may find the remains of a village and study the artifacts Inferences Proposed explanations for what you have seen Example: Archeologists may infer from the artifacts found that the inhabitants of the village were farmers

SCIENCE AND NONSCIENCE Science Cannot use supernatural explanations; these cannot be critically tested Can only answer questions about the natural world Limited ability to answer questions about the supernatural, ethics, beauty, opinions, politics, beliefs, or feelings Astronomy is a science because it is the study of the stars/planets/universe and data is collected that can be used to make predictions. Science is durable and open to change Nonscience Uses supernatural explanations Based on opinion and faith Astrology is called a pseudoscience because it uses a natural phenomenon (star/planet positions) to provide answers to untestable questions.

QUALITATIVE VS. QUANTITATIVE DATA Qualititative Data that is described in words without numbers. The cat has long fur. The cat has gray fur. Quantitative Data that is expressed in numerical form There are 4 cats in the cage. The cat has 6 toes on one paw.

DEVELOPMENT OF TECHNOLOGY IS ESSENTIAL FOR NEW INFORMATION An example of this is the development of the microscope. Before the microscope, we did not know cells existed. Different scientists using this new invention discovered different information about cells. Their ideas eventually formed Cell Theory.

TYPES OF MICROSCOPES: LIGHT MICROSCOPE This is the kind we use in our class. 2 dimensional view Object to be viewed may be alive Uses several lenses to magnify and focus the object Magnification from x

ELECTRON MICROSCOPES Transmission-TEM Uses a beam of electrons transmitted through the thin slice of the material to be studied 2 dimensional picture Magnifies >100,000 times Object cannot be alive due to processing Very expensive Often used in research Scanning-SEM Uses a beam of electrons to scan the surface of the object 3 dimensional picture Magnifies >100,000 times Objects cannot be alive due to processing Very expensive Used some in research, but more often for making pictures used in illustrations Images are often artificially colored for effect. Both kinds of scopes only take black and white pictures.

IMAGES FROM ELECTRON MICROSCOPES TransmissionScanning