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Questions and Answers
What is the primary focus of the scientific method?
Which of the following describes a hypothesis?
Which statement about theories is true?
What differentiates basic science from applied science?
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What is the role of controlled variables in an experiment?
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What type of reasoning involves making general conclusions from related observations?
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Which of the following is NOT a scientific discipline mentioned?
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What does the acronym E=mc^2 represent in science?
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Why is chemistry important to understand biology?
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What are the building blocks of all matter?
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What are the three subatomic particles that make up an atom?
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What is the mass number of an atom?
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What is the atomic number of an element?
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What does the octet rule state regarding outer shell electrons?
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Cations have a negative charge because they gain an electron.
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What is a covalent bond?
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Which type of bond is considered the strongest in living organisms?
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What is the role of buffers in the human body?
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The pH scale measures the concentration of ______ ions.
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What happens to Carbon-14 over time?
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Study Notes
Science
- Science is a systematic and logical approach to discovering how things work.
- It's derived from the Latin word "scientia" meaning knowledge.
- Science covers many different topics.
Science vs. Anecdote
- Anecdotes, individual stories, can suggest areas for scientific investigation but are not reliable evidence.
- Scientific understanding relies on large samples and average outcomes.
- Example: A single child developing autism after vaccination does not prove a link, large-scale studies show no correlation between vaccines and autism.
Science Disciplines
- Physics
- Chemistry
- Astronomy
- Logic
- Biology
- Mathematics
- Computer Science
- Geology
Logical Thinking Methods
Inductive Reasoning
- Uses related observations to draw general conclusions.
- Data can be qualitative or quantitative.
- Requires large amounts of data.
Deductive Reasoning
- Uses a hypothesis to predict specific results in controlled experiments.
- This is the foundation of the scientific method.
Scientific Method
- First documented by Sir Francis Bacon in the 1500s.
- Requires empirical or measurable evidence.
- Results must be repeatable.
Hypothesis
- An explanation based on limited evidence that can be tested.
- Must be testable and falsifiable.
- Can be disproven but never proven.
Experiments
- Designed to test a hypothesis.
- Variables:
- Independent variable (what is changed)
- Dependent variable (what is measured)
- Controlled variables are kept constant.
Challenge Statement
- Hypothesis can lead to theories and laws, but this is not a linear process.
- Strong agreement and consistent evidence are needed to move from hypothesis to theory, and theory to law.
Hypothesis, Theories, & Laws
- Long-standing hypotheses can become theories.
- Theories can't be proven and never become laws.
- Laws are consistently proven observations, often represented by mathematical equations, like E=mc2.
Basic Science vs. Applied Science
- Basic science pursues knowledge for the sake of understanding, regardless of immediate benefit.
- Applied science develops technology to address real-world problems.
Chemistry is Important to Understand Biology
- The human body is composed of protons, neutrons, and electrons.
What are Elements
- Elements are the building blocks of matter.
Anatomy of an Atom
- Atoms are composed of subatomic particles:
- Protons: Positively charged
- Electrons: Negatively charged
- Neutrons: No charge
Atoms
- Atoms contain all properties of an element
- Mass number is the sum of protons and neutrons
- Electrons have negligible mass
- Atomic number equals the number of protons
- The number of protons generally equals the number of electrons
Reading the Periodic Table
- Columns represent the number of electrons in the outer shell
- Rows represent the number of electron shells
Understanding Valence Electrons
- Valence electrons are located in the outermost shell and determine the atom's reactivity.
Chemical Bonds
- Atoms seek to fill their outer electron shells for greater stability.
- Outer shells can be filled by:
- Sharing electrons (covalent bonds)
- Donating electrons (ionic bonds)
- Accepting electrons (ionic bonds)
- Most outer shells hold 8 electrons (octet rule)
Ions & Ionic Bonds
- Ions are atoms with an unequal number of protons and electrons.
- Cations have a positive charge and have lost electrons
- Anions have a negative charge and have gained electrons
- Electrons are transferred in ionic bonds, resulting in:
- Cations donating electrons
- Anions accepting electrons
- Ionic bonds are very strong and result in the octet rule being satisfied
- For example, in sodium chloride (NaCl):
- Sodium (Na) donates an electron
- Chlorine (Cl) accepts an electron
- both achieve a stable outer shell
- For example, in sodium chloride (NaCl):
Covalent Bonds
- Covalent bonds occur when atoms share electrons to fill their outer shells.
- They are the strongest and most common type of bond in living organisms.
- Covalent bonds do not dissociate in water, unlike ionic bonds.
- Covalent bonds can be:
- Polar: Unequal sharing of electrons due to differences in electronegativity (example: water)
- Nonpolar: Equal sharing of electrons (example: methane)
Hydrogen Bonds
- Hydrogen bonds are weak bonds between polar covalent molecules containing hydrogen.
- The positively charged hydrogen atom attracts the negatively charged portion of another molecule.
- These bonds are responsible for many of water's life-sustaining properties.
Van Der Waals Interactions
- Weak attractive forces between molecules due to temporary partial charges caused by electron movement
Isotopes & Carbon Dating
- Isotopes are atoms of the same element with different numbers of neutrons.
- Example: Carbon-12 and Carbon-14
- Some isotopes are radioactive and decay over time.
- The decay process involves neutrons transforming into protons
- Carbon dating utilizes the predictable decay rate of Carbon-14 to estimate the age of fossils and artifacts.
- Every 5,730 years, half of Carbon-14 decays into Nitrogen-14
- The concentration of Carbon-14 in remains is compared to its concentration in the atmosphere.
Anatomy of an Atom: Changing Subatomic Particles
- Changing the number of protons creates a new element.
- Changing the number of electrons creates an ion.
- Changing the number of neutrons creates an isotope.
All about pH
- Water constantly dissociates into H+ and OH- ions and reforms back into water.
- pH is a measure of hydrogen ion (H+) concentration.
- pH 7 is neutral (equal H+ and OH-)
- pH < 7 is acidic (more H+)
- pH > 7 is basic (more OH-)
- The pH scale is logarithmic, meaning each unit represents a 10x change in H+ concentration.
Calculating H+ Concentration from pH
- The pH is the negative logarithm of the H+ ion concentration.
- Equation: pH = - log10(H+)
All about pH
- The human body maintains a pH range of 7.2 to 7.6.
- Buffers help maintain pH stability.
- Carbon dioxide (CO2) is crucial to our buffer system.
Carbonic Acid-Bicarbonate Buffer System
- When blood pH rises (becomes more basic):
- Carbonic acid (H2CO3) dissociates into bicarbonate (HCO3-) and H+, reducing the pH.
- Reaction: H2CO3 -----> HCO3- + H+
- Carbonic acid (H2CO3) dissociates into bicarbonate (HCO3-) and H+, reducing the pH.
- When blood pH drops (becomes more acidic):
- Bicarbonate (HCO3-) combines with H+ to form carbonic acid (H2CO3), increasing the pH.
- Reaction: HCO3- + H+ -----> H2CO3
- Bicarbonate (HCO3-) combines with H+ to form carbonic acid (H2CO3), increasing the pH.
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Description
This quiz explores the fundamental concepts of science, its branches, and the distinction between scientific evidence and anecdotal claims. It covers logical reasoning methods, including inductive and deductive reasoning, essential for scientific investigation. Test your knowledge on various disciplines within science and their approaches.
