what is science? - dwight public schools what is science ch. 1.pdf · what is science? what is...
TRANSCRIPT
What is Science?
What is science?
What is Biology?
Are they the same?
Do they share the same goals?
Science is…• Science is a term that goes beyond simple
definitions
• It tries to
– solve the worlds problems
– answer the worlds questions,
– and yet its limits outstretch the universe…
• It is everywhere… involves everything
Go for the goal…
• We could just say science is everything… but that oversimplifies our complex field.
• So instead, we define it by its goal
• Your book defines the goal of science as:• The investigation and
understanding of the natural world in order to explain events and questions.
• In our class the goal of science is:
So… What is Science?• Science is an organized way of using Evidence
to learn about the world around us.
– This is what is meant by NATURAL reasoning and a NATURAL world and universe
– This is why we do not teach religion in a science classroom
• Religion is based in FAITH. Science is based in evidence found within nature
• Do not confuse faith with fiction… Just because religion is faith-based does not make it fake, it just makes it non-scientific…
An Organized Way
• Science has a specific method for carrying out its processes called the scientific method
• If done properly, the scientific method can be used in nearly every aspect of life.
– It is not just a method, it is a way of thinking… It is a way of living
• It all starts with a hypothesis…
The Scientific Method of Thinking
Hypothesis?
A Scientific Hypothesis is…
• It must be TESTABLE!
• It should not be phrased as a question
• Sometimes it requires multiple experiments to test completely
• A hypothesis that is incorrect can tell a lot!!!
Theory
• If your hypothesis proves correct, it is called a theory.
– NOT A FACT!
– There are NO facts in science
– Only theories that have not yet been incorrectly proven
Longest Running
• The oldest and longest believed scientific FACTis that the universe is geocentric (geo= earth, centric= centered)
• Science is ALWAYS changing and is not based on FACTS!
• And Scientists must forever be bettering there experiments, methods, and ideas
As society evolves and science grows we know one thing to be a true fact… Facts tend to close the mind and hinder the goals of science!
A theory gone wrong…
• For hundreds of years, society believed that many lesser forms of life came from circumstantial nonlife
• Maggots came from meat setting on a table and mold would form if you left bread uncovered.
• It even went as far as to say mice form from food being left out in a barn…
Why question the norm?
• This theory was called spontaneous generation because it said lesser life (like mold, insects, and rodents) formed from nonlife…
• As ridiculous as this theory may seem to our modern society, it was accepted as fact for centuries
Simple Observations
• Francesco Redi conducted simple observations by noting that meat seemed to have maggots only after flies landed on the meat
• Other scientists that we will talk about later in the semester like Rudolf Virchow, Anton van Leuwenhoek, and Lorenzo Spallanzani also began to attack this societal theory
Louis Pasteur • The theory of spontaneous was eventually put
to rest by the experiments done by Louis Pasteur.
• Pasteur created a special flask which ended the debate
• The flask contained gravy, unsealed in flask, with a swan neck
• This specialized flask allowed air flow but prevented bacteria covered dust from entering the gravy
• This allowed the gravy to stay free of microbes
Open Mind and Good Experiments• The experiments done by Redi, Virchow, van
Leuwenhoek, Spallanzani, and Pasteur were not overly complicated,
• They just didn’t accept what society considered a fact
• They observed a problem• Controlled the experiment• Manipulated one SINGLE VARIABLE• Collected the data• Formed a conclusion• And in some instances, formed a new hypothesis
and experiment
Good Science Method
• Starts with the observation of a problem
• A testable educated guess (Hypothesis) is formed as to what the answer may be
• An experiment is formed with all variables controlled (kept the same) except one (the manipulated/independent variable)
• Data is collected (the dependent variable)
• A conclusion is drawn
• Occasionally a new hypothesis/experiment must be created…
What is Biology?
• Biology is a branch of science like astronomy, psychology, chemistry, and physics…
• It has the same overall goals as science (using natural reasoning to answer questions)
• However, biology focuses on studying, answering, and using natural evidence to better understand Life
What does it mean to be alive?
Characteristics of Life as We Know It
• Are made up of one or more units called cells
• Reproduce
• Based on a Universal Genetic Code
• Grow and develop
• Obtain and use energy
• Respond to their environment
• Maintain a stable internal environment
Living Things Are Made Up of Cells
• Small self-contained units called cells
• All are living material enclosed by some form of a membrane that separates it from its surroundings
• Filled with living matter
• Smallest unit of life
Reproduce
• All living things can reproduce– Make new organism of the same species
• Sexual Reproduction– Requires that 2 cells from different individuals
unite to produce the first cell of a new individual
• Asexual Reproduction– A single organism may reproduce without the aid
of another• This can be as simple as just one individual dividing to
make 2 individuals
Based on a Universal Genetic Code
• All of life uses a long double strand of nucleic acids to create their blueprints of life
• We call this group of nucleic acids Deoxyribonucleic Acid (DNA)
– it is assisted by a nucleic acid that is generally found as a single strand called Ribonucleic Acid (RNA)
Living Things Grow and Develop
• All living things, at one stage or another, are capable of growth and development
• Often times, even after something stops growing, it still continues to add new material
• With growth comes aging
– Aging is an organism becoming less efficient at the processes of life
Obtain and Use Energy
• Living things obtain energy from their environment, or their environment, and use that energy to grow, develop, and reproduce.
• They use energy to build the substances that make up their cells
• Anabolism: The process of living things putting things together or synthesizing complex substances
• Catabolism: The final break down of complex substances, into simpler ones, in order to release energy
Remember
• Money = Energy in Biology
• The cheaper a process is, the better it is for your check book
Mouse vs. Elephant
• Which of the above organisms would you expect to have a harder time staying warm when it gets cold outside
Surface Area
• The smaller an organism is the larger its surface area.
– The higher the amount of surface exposed to the outside elements (vs. internal mass)
– It is a surface to volume ratio
– The larger the organism the greater the volume
• Small organisms have a high surface area
• Large organisms have a small surface area
Living Things Respond to Their Environment
• Response to an environment has become essential for life
• Selective pressures eliminate and create species all the time
• The process by which organisms respond to stimuli in ways that keep conditions in their body suitable for life is called Homeostasis
• It is through homeostasis that our bodies are able to remain suitable for life
• Example: Tropisms (Gravi, photo)
Maintain Internal Balance
• When we go outside on a cold day, our body temperatures do not drop drastically (which is a good thing)– Why?????
• Nearly all life has process inside their bodies that keep variables like temperature and water levels constant, despite outside conditions…– This is called
BIOLOGY
• Bio = Life
• logy = Study of
• Bio-logy = The Study of Life
Biologist
• So what is a “Biologist??”
• A biologist is somone who uses the SCIENTIFIC METHOD and CRITICAL THINKING to study
Forming an inference…
Technology Advancements
• Science is restricted by a lack of technology
• As our scientific tools (technology) advance, so advances our ability to do science… to invent… to understand… to fix…
• Think about how much science changed with the advancements in a simple microscope…
Compound Microscopes
• Compound Light Microscope: Uses 2 Lenses to make up one larger image
– Will have a LIMIT of RESOLUTION• The point at which further magnification will cause a decrease in
resolution (BLURRY!)
– Even a perfect compound microscope will have a Limit of Resolution (LoR)
• One of the best ways to view an item in a Compound Microscope is by staining them
• The average compound microscope’s Limit of Resolution is = .2 micrometers (an average cell = 10 micrometers)
Electron Microscopes
• SEM: Scanning Electron Microscope– A beam of electron particles scan back and forth
across an image and are picked up by receptors• Gives a 3-D image of the outside of an item
• Exceptional for viewing tiny organisms
– Drawbacks:• Organism must be dead and completely dry
• Only works if organism is placed in a vacuum
• Not cheap
SEM
SEM
SEM
Electron Microscopes
• Transmission Electron Microscopes:– Shines a beam of electrons that magnifies the
image onto a fluorescent screen
– Excellent for internal magnifications and cell parts
• Drawbacks:– Object must be dead
– Object must be completely free of moisture
– Object must be sliced extremely thin
– Object must be placed in a vacuum
TEM
TEM
TEM
Scanning Probe Microscope
• Very new microscope discovered in the 80s
• Do not use lenses
• Use an insanely fine tip to scan the surface of an object
• Can magnify so well that it actually allows the view of individual atoms
• Does not require the object to be placed in a vacuum
SPM or PM
SPM
SPM
SPM
Metric System
• Science use SI units when collecting data and doing calculations– SI = International System of measurements
• This means that it is used by all nations…
• Why is it not called IS units?????
• It is based on a Base 10 System– This means it is arranged in multiples of ten
• There are exactly ten units between centimeters and millimeters
• EVERYTHING we do in here should be in SI units!
Mars Probe