Unit 1Unit 1Unit 1Unit 1

Scientific InquiryScientific Inquiry

SC Standard•B-1.1 Generate hypotheses

on the basis of credible, accurate, and relevant sources of scientific information.

1. A hypothesis is a reasonable explanation of an observation or experimental result or a possible answer to a scientific question that can be tested.

2. The hypothesis may or may not be supported by the experimental results.

3. The hypothesis is often stated in terms of an independent and a dependent variable—or a “cause-effect relationship.”

4. Examples of hypotheses might include:

• If an object has greater surface area, then the rate at which it falls through the air decreases.

• As the volume of an object increases, the rate at which it fall through air decreases.

• With a constant force, an object with a smaller mass will accelerate more than an object with a larger mass.

• If I make a paper airplane with larger wings, then the airplane will glide farther, because the additional surface area of the wing will produce more lift.

5. The results of an experiment cannot prove that a hypothesis is correct. Rather, the results support or do not support the hypothesis.

6. Valuable information is gained even when the hypothesis is not supported by the results. For example, it would be an important discovery to find that the wing size is not related to how far an airplane glides. When hypotheses are tested over and over again and not contradicted, they may become known as laws or principles.

7. Use credible (trustworthy), accurate (correct – based on supported data), and relevant (applicable, related to the topic of the investigation) sources of scientific information in preparation for generating a hypothesis.

8. These sources could be previous scientific investigations science journals, textbooks, or other credible sources, such as scientifically reliable internet sites.

SC StandardB-1.2 Use scientific

instruments to record measurement data in appropriate metric units that reflect the precision and accuracy of each particular instrument.

9. Read scientific instruments such as graduated cylinders, balances, spring scales, thermometers, rulers, meter sticks, ammeters, voltmeters (or multimeters), and stopwatches using the correct number of decimals to record the measurements in appropriate metric units.

10. the terms precision and accuracy are widely used in any scientific work where quantitative measurements are made.

• Precision is a measure of the degree to which measurements made in the same way agree with one another.

• The accuracy of a result is the degree to which the experimental value agrees with the true or accepted value.

• It is possible to have a high degree of precision with poor accuracy. This

occurs if the same error is involved in repeated trials of the experiment.

SC StandardB-1.3 Design a scientific investigation with appropriate methods of control to test a hypothesis (including independent and dependent variables), and evaluate the designs of sample investigations.

11. The steps in designing an investigation include:

• Stating the purpose in the form of a testable question or problem statement

• Researching information related to the investigation

• Stating the hypothesis• Describing the experimental process

Planning for independent and dependent variables with repeated trials Planning for factors that should be

held constant (controlled variables)

Setting up the sequence of steps to be followed Listing materials Planning for recording, organizing and analyzing data

• Planning for a conclusion statement that will support or not support the hypothesis

12. Scientific investigations are designed to answer a question about the relationship between two variables in a predicted “cause-effect relationship.”

13. The statement that predicts the relationship between an independent and dependent variable is called a hypothesis.

14. The independent variable is the variable that the experimenter deliberately changes or manipulates in an investigation.

15. The dependent variable is the variable that changes in an investigation in

response to changes in the independent variable.

16. The independent variable is the “cause” and the dependent variable is the “effect” in

the “cause-effect” relationship that is predicted.

17. All the other possible variables in the investigation should be held constant so that only one variable (the independent) is tested at a time. The variables which are held constant are called controlled variables.

18. The investigator should conduct repeated trials to limit random error in measurements.

19. A control group is set up as a basis of comparison to test whether the effects on

the dependent variable came from the independent variable or from some

other source.

SC StandardB-1.4 Organize and interpret the data from a controlled scientific investigation by using mathematics (including formulas and dimensional analysis), graphs, models, and/or technology.

20. Organize data which is collected from a controlled scientific investigation in tables and graphs.

o Data should be organized in charts which list the values for the independent variable in the first column and list the values for the dependent variable in a column to the right of the independent variable.

Examples

Independent Dependent Variable Variable

21. Data should be recorded on a graph with the independent variable plotted on the “X” axis (MIX) and

the dependent variable plotted on the “Y” axis (DRY).

o Choose scales for both the horizontal axis and the vertical axis.

• There should be two data points more than is needed on the vertical axis.

• horizontal axis should be long enough for all of the data points to fit.

The intervals on each axis should be marked in equal increments

• Label each axis with the name of the variable and the unit of measure.

• Title the graph.• Use the graphs to analyze and interpret data to

determine a relationship between the dependent and independent variables.

• A line graph is used for continuous quantitative data.

• o A bar graph is used for non-continuous data which is usually categorical.

• o A circle graph shows a relationship among parts of a whole. Circle graphs often involve percentage data.

• · Recognize the implications of various graphs

22. A direct variation (or proportion) is one in which, one variable increases as the other increases or as one variable decreases the other decreases.

• A straight line with a positive slope indicates a direct relationship that changes at a constant rate.

• A greater slope indicates an increased rate of change.

23. An inverse variation (or proportion) is one in which the product of two quantities is a constant. (as one variable goes up, the other one goes down AND VICE VERSA)

• For example the product of the frequency and the wavelength is equal to the velocity of a wave (v = f λ). Frequency and wavelength are inversely proportional. As one quantity increases the other quantity decreases.

24.  Use a formula to solve for one variable if given the value for the other variables.

• example: Volume = length x Width x Height

25. Use dimensional analysis to change the units of the measurement determined, not the value of the measurement itself.

26. It is very important in science to express all numbers with units of measurement when appropriate, not just the number as is sometimes done in purely mathematical problems.

o To change a measurement from liters to milliliters, or grams to kilograms, for example, the measurement can be multiplied by a “conversion factor” that expresses the relationship between the given and asked- for value.

o This conversion factor is a fraction equal to one and, therefore, the value of the

original measurement does not change---only the unit changes.

27. A scientific model is an idealized description of how phenomena occur and how data or events are related.

• A scientific model is simply an idea that allows us to create explanations of how we think some part of the world works. Models are used to represent a concept or system so that the concept may be more easily understood and predictions can be made.

• The model of the atom helps us understand the composition, structure, and behavior of atoms. Models for the atom can change as new information and theories explain the atom more

completely.

• No model is ever a perfect representation of the actual concept or system.

• Models may change over time as scientific knowledge advances.

28. Technology (tools/machines or processes) can be used to develop better understanding of the science concepts studied.

• As technology improves, science concepts are studied more

completely and more accurately.

SC StandardB-1.5 Evaluate the results of a controlled scientific investigation in terms of whether they refute or verify the hypothesis.

29. In a controlled scientific investigation the hypothesis is a prediction about the relationship between an independent and dependent variable with all other variables being held constant.

30. Results of a controlled investigation will either refute the hypothesis or verify by supporting the hypothesis

• After the hypothesis has been tested and data is gathered, the experimental data is reviewed using

data tables, charts, or graphical analysis.

• If the data is consistent with the prediction in the hypothesis, the hypothesis is supported or verified.

• If the data is not consistent with the prediction in the hypothesis, the hypothesis is refuted.

31. The shape of a graph can show the relationship between the variables in the hypothesis.

32. If the data does support the relationship, the hypothesis is still always tentative and subject to further investigation.

• Scientists repeat investigations and do different investigations to test the same hypothesis because the hypothesis is always tentative, and another investigation could refute the relationship predicted.

33. Scientific laws express principles in science that have been tested and tested and always shown to support the same hypothesis.

• Even these laws, however, can be shown to need revision as new scientific evidence is found with improved technology, advanced scientific knowledge, and more controlled scientific investigations based on these.

SC StandardB-1.6 Evaluate a technological design or product on the basis of designated criteria (including cost, time, and materials).

34. Technological designs or products are produced by the application of scientific knowledge to meet specific needs of humans. The field of engineering focuses on these processes.

35. There are four stages of technological design:o Problem identificationo Solution design (a process or a

product)o Implementationo Evaluation

36. Common requirements within the solution design stage of all technological designs or products include:

o Cost effectiveness or lowest cost for production;

o Time effectiveness or the least amount of time required for production, and

o Materials that meet specific criteria, such as:§ Solves the problem§ Reasonably priced§ Availability

§ Durability§ Not harmful to users or to the environment§ Qualities matching requirements for product or solution§ Manufacturing process matches characteristics of the material

37. Benefits need to exceed the risk.38. There are tradeoffs among the

various criteria. For example, the best material for a specific purpose may be too

expensive.

SC StandardB-1.7 Compare the processes of scientific investigation and technological design.

39. Science is a process of inquiry that searches for relationships that explain and predict the physical, living and designed world.

40. Technology is the application of scientific discoveries to meet human needs and goals through the development of products and processes.

41. The processes of scientific investigation are followed to determine the relationship between an independent and dependent

variable described by a hypothesis.

42. The results of scientific investigations can advance science knowledge.

43. The processes of technological design are followed to design products or processes to meet specified needs.

44. The results of technological designs can advance standard of living in societies.

44. The field of engineering is responsible for technological designs or products by applying science to make products or design processes that meet specific needs of mankind.

· The process of controlled scientific investigations:

o Asks questions about the natural world;

o Forms hypotheses to suggest a relationship between dependent and independent variables;

o Investigates the relationships between the dependent and independent variables;

o Analyzes the data from investigations and draws conclusions as to whether or not the hypothesis was supported.

· The technological design process is used to design products and processes that people can use.

46. The process may involve:o A problem or need is identifiedo A solution is designed to meet the need or

solve the problem identified.o The solution or product is developed and

tested.o The results of the implementation are

analyzed to determine how well the solution or product successfully solved the problem or met the need.

47. Scientific Investigation Technological Design

• Identifies a problem – asks a question Identifies a problem or need

• Researches related information Researches related information• Designs an investigation or experiment

Designs a process or a product• Conducts the investigation or experiment

– repeated trials• Conducts the investigation or experiment

– repeated trials• Implements the design or the

process – Repeated testing

• Analyzes the results Analyzes the results • Evaluates the conclusion – did the

results refute or verify the hypothesis

Evaluates the process or product – did it meet the criteria• Communicates the findings

Communicates the product or process

Comparison of scientific investigations and technological

designsScientific Investigations Technological Designs

Identifies a problem – asks a question

Identifies a problem or need.

Researches related information Researches related information

Designs an investigation or experiment

Designs a process or a product

Conducts the investigation or experiment – repeated trials

Implements the designs or the process – repeated trials

Analyzes the results Analyzes the results

Evaluates the conclusion – did the results refute or verify the hypothesis.

Evaluates the process or product – did it meet the criteria.

Communicates the findings Communicates the product or process.

SC StandardB-1.8 Use appropriate safety procedures when conducting investigations.

48. safety procedures regardingo Personal safety – • follow only the designated lab procedures; • be sure to understand the meaning of any

safety symbols shown, • wear proper clothing and shoes for the

lab, • use protective equipment (goggles,

aprons,…), • tie back loose hair, • never eat or drink in lab room, • use proper technique for touching or smelling materials.

o Work area safety – • use only designated chemicals or

equipment, • keep work area clear and uncluttered, • do not point heated containers at

yourself or anyone else, • be sure all burners or hot plates are

turned off when the lab is finished, • know the location and use of the fire

extinguisher, safety blanket, eyewash station, safety shower, and first aid kit,

• disconnect electrical devices, • follow clean-up procedures as designated by the teacher.

• Safely and accurately practice appropriate techniques associated with the equipment and materials used in the activities conducted in the laboratory and classroom

• Abide by the safety rules in the course safety contract.

• Report any laboratory safety incidents (spills, accidents, or injuries) to the teacher.

Activity:• p. 20, Science on the Internet

B. 1.9 Chemistry of LifeChap 2

49. Everything in the universe is made of matter50. Matter = anything that occupies space and has mass.51. Mass = the quantity of matter an object has.52. Weight = the force produced by gravity

acting on mass.

53. Weight can change due to the amount of gravity present; whereas, mass stays the same and is not dependent on gravity.54. Elements = substances that cannot be broken down chemically into simpler kinds of matter.55. More than 100 elements have been identified, though fewer than 30 are important to living things.

http://www.privatehand.com/flash/elements

http://

56. More than 90% of the mass of living things is composed of combinations of just four elements: Oxygen, carbon, hydrogen, and nitrogen.57. Periodic Table = chart that summarizes the elements.•Each elements has a different chemical symbol.•Chemical symbols consist of 1, 2, or 3 letters, usually the first letter or other letters in the name or letters from the Latin name.

58. Atom = the smallest particle of an element that retains all of the properties of that element.59. The properties of different kinds of atoms determine the structure and properties of the matter they compose.60.The nucleus (central region) makes up the bulk of the atom’s mass.61. Three parts of the atom:

– Protons = positive charge (inside the nucleus)– Neutrons = neutral charge (inside the nucleus)– Electrons = negative charge (circle outside the

nucleus in orbitals)– www.youtube.com/watch?v=zUDDiWtFtEM&featur

e=em-share_video_user

62. Orbital = a three-dimensional region around the nucleus that indicates the possible location of electrons.63. The more energy an electron has the farther away from the nucleus it will move.64. Orbitals correspond to specific energy levels.65. Each energy level corresponds to a group of orbitals that can hold only a certain total number of electrons.

Activity: Color Periodic tables

66. Since it is the number of protons that identifies the atom, the number of protons does not normally change.67. Isotopes = Atoms of the same element that have a different number of neutrons (this changes the mass of the atom).68. Under natural conditions, most elements do not exist alone; atoms can readily combine with the same or different atoms. Activity: Do Element Charts

68. Compounds = atoms of two or more elements in fixed proportions.69. The atoms that make up the compounds have different physical and chemical properties from the compound.70. An atom is chemically stable when the orbitals that correspond to its highest energy level are filled with the maximum number of electrons.71. Some elements consist of atoms that have the maximum number of electrons in the orbitals of their highest energy level.

72. These elements are called noble or inert elements. They do not react with other elements under normal conditions.73. Most elements tend to interact with other atoms to form chemical bonds.74. Chemical bonds = the attractive forces that hold atoms together.•Covalent Bonds = form when atoms share one or more pairs of electrons (A molecule is the simplest part of a covalent bond that retain all of the properties of that substance and can exist in a free state).

• Ionic Bonds = form when atoms transfer electrons and form ions, which are atoms with an electrical charge: cations are positive and anions are negative.

• Hydrogen Bonds = the force of attraction between a hydrogen molecule with a partial positive charge and another atom or molecule with a partial negative charge. Water molecules stick to each other as a result of hydrogen bonding.– Cohesion = an attractive force that holds

molecules of a single substance together – (contributes to the upward movement

of water from plant roots to their leaves).

– Adhesion = the attractive force between two particles of different substances, such as water molecules and glass molecules.

– Capillarity = the attraction between molecules that results in the rise of the surface of a liquid when in contact with a solid.

75. Together adhesion, cohesion, and capillarity help water rise through narrow tubes against the

force of gravity.

Chemical Bonding• Covalent Bonding:

– 2 nonmetals combining– Shared electrons (no charge is produced)– 4, 5, 6, or 7 valence electrons– Produces substances called molecules

Chemical Bonding• Ionic Bonding:

– One metal and one nonmetal combining– Electrons are transferred (metal loses and nonmetal

gains electrons)– 1, 2, or 3 valence electrons, atoms will lose electrons

(metals)– 4, 5, 6, or 7 valence electrons, atoms will receive

electrons (nonmetals)– Produces ions (cations are positive, which are metals

and anions are negative, which are nonmetals)

– Produces substances called Crystals

Practice bonding:1.C and H2.N and Li 3.O and C 4.Mg and Cl5.F and N6.Na and Cl7.P and S8.K and Br

76. Energy =The ability to do work.77. Energy can occur in various forms and one form can be converted to another form.78. All the atoms and molecules in any substance are in constant motion.79. The motion of and spacing between atoms or molecules of a substance determine the substance’s state: •Solid = fixed volume and shape•Liquid = fixed volume but no fixed shape (particles are loose and can slip past each other).

–Gas = no fixed volume or shape (moves the fastest).

80. Thermal (heat) energy must be added are taken away from a substance in order for it to change states.81. In a chemical reaction, one or more substances change to produce one or more different substances.82. Energy is absorbed or released when chemical bonds are broken and new ones are formed.83. Reactants are shown on the left side

of the chemical equation and products are shown on the right side.

83. For most chemical reactions to begin, energy must be added to the reactants.84. Activation energy = the energy needed to start a chemical reaction.85. Catalysts = chemical substances used to speed up reactions (reduce the amount of activation energy needed to start the reaction).86. An enzyme = a protein or RNA molecule that speeds up metabolic

reactions without being permanently changed or destroyed.

87. The reactions in which electrons are transferred between atoms are known as oxidation-reduction reactions (or redox reactions).•Oxidation reactions = a reactant loses one or more electrons, thus becoming more positive in charge.•Reduction reaction = a reactant gains one or more electrons, thus becoming more negative in charge.

88. Polar = the uneven distribution of charge in a covalent molecule (ex: water)89. Water can only dissolve substances that are polar also.90. Solution = a mixture in which one or more substances are uniformly distributed in another substance. •Solute = a substances dissolved•Solvent = The dissolving medium.91. The concentration of a solution is the

amount of solute dissolved in a fixed amount of solution.

92. A saturated solution is one in which no more solute can dissolve.93. Aqueous Solution is one in which water is the solvent (most chemical reactions that occur in the body occur in aqueous solutions).94. As water molecules move about, they bump into each other and causes a chemical reaction in which water splits into H (positive) and OH (negative).

95. OH- = hydroxide ionH2O+ = hydronium ion96. Acids = a solution in which the number of hydronium ions is greater than the number of hydroxide ions (sour taste).97. Bases = a solution in which the number of hydroxide ions is greater than the number of hydronium ions (bitter taste and slippery feel).

98. pH Scale = compares the relative concentration of hydronium ions and hydroxide ions (ranges from 0-14: 7 neutral, below 7 is a acid; above 7 is a base).99. The pH of a solution can be measured with litmus paper: red = acid, blue = base.100. The control of pH is important for living systems, because enzymes can function only within a very narrow pH range.

101. Buffers = chemical substances that neutralize small amounts of either an acid or a base added to a solution.

p. 38

BiochemistryChap 3

102. All compounds can be classified in two broad categories: organic compounds and inorganic compounds.103. Most matter in living organisms that is not water is made of organic compounds.104. Organic compounds contain carbon,

and almost all inorganic compounds do not contain carbon.

105. Since a carbon atoms has four valence electron, it forms four covalent bonds with other atoms.106. Carbon can also bond with other carbon atoms, forming straight chains, branched chains, or rings (look on p. 51).107. The tendency of carbon to bond with itself results in an enormous variety of organic compounds.108. A bond formed when two atoms share a pair of electrons is called a single bond.

109. A carbon atom can also share two or even three pairs of electrons with another atom.110. A double bond is represented by 2 parallel lines and a triple bond is represented by 3 parallel lines. (p. 52, figure 3.2)

111. In most compounds, clusters of atoms, called functional groups, influence the characteristics of the molecules they compose and the chemical reactions the molecules undergo. (p. 53, figure 3.1)112. Many carbon compounds are built up from smaller, simpler molecules known as monomers.

113. Monomers can bond together to form a polymer (a molecule that consists of repeated, linked units).114. Large polymers are called macromolecules.115. There are many types of macromolecules: carbohydrates, lipids, proteins, and nucleic acids.116. Monomers link to form polymers through a chemical reaction called a

condensation reaction.

117. Each time a monomer is added to a polymer, a water molecule is released.118. The breakdown of some complex molecules, such as polymers, occurs through a process known as hydrolysis.119. In a hydrolysis reaction, water is used to break down a polymer.120. Hydrolysis is the opposite of condensation reaction.121. Life processes require a constant

supply of energy.

122. This energy is available to cells in the form of certain compounds that store a large amount of energy in their structure (ex: ATP = adenosine triphosphate).123. Carbohydrates (sugars and starches) = organic compounds composed of carbon, hydrogen, and oxygen in a ratio of about one carbon to two hydrogen atoms to one oxygen atom (made of monomers called monosaccharides which are simple sugars).

124. In living things, two monosaccharides can combine in a condensation reaction to form a double sugar, disaccharide (ex: glucose + fructose = sucrose).125. A polysaccharide is a complex molecule composed of three or more monosaccharides.126. Animals store glucose in the form of the polysaccharide glycogen (hundreds of glucose molecules that are used for quick energy).

126. Plants store glucose molecules in the form of polysaccharides called starch.127. Plants also make large polysaccharides called cellulose, which gives strength and rigidity to plant cells.128. Cellulose makes up about 50% of wood.129. Proteins = organic compounds composed mainly of carbon, hydrogen, oxygen, and nitrogen.

130. Proteins are made from monomers called amino acids.

131. Hair, horns, skin, muscles, and enzymes are made of proteins. 132. There are 20 different amino acids with a basic structure (p. 56, figure 3.7).133. In condensation reactions two amino acids form a covalent bond called a peptide bond.134. Amino acids also form very long chains called polypeptides.135. Enzymes, RNA or proteins, that act

as biological catalysts, are essential for the functioning of cells.

136. Enzyme reactions depend on a physical fit between the enzyme molecule and its specific substrate, the reactant being catalyzed.137. Enzymes have folds, or an active site, with a shape that allows the substrate to fit into the active site.138. An enzyme acts only on a specific substrate because only that substrate causes a slight change in the enzyme’s

shape.

139. The change in the enzyme’s shape weakens some chemical bonds in the substrate, which is one way that enzymes reduce activation energy, the energy needed to start the reaction.140. After the reaction, the enzyme releases the products. Like any catalyst, the enzyme itself is unchanged, so it can be used many times.141. Enzymes cannot work in certain environment, such as temperature or pH changes, because the shape of

the enzyme can change.

142. Lipids (fats and oils = large, nonpolar molecules which do not dissolve in water.143. Lipids include triglycerides, phospholipids, steroids, waxes, and pigments (read p. 59-60). 144. Because lipid molecules have larger numbers of carbon-hydrogen bonds per gram than other organic compounds do, they store more energy per gram. 145. Nucleic acids = very large and

complex organic molecules that store and transfer important information in the cell.

146. Two important nucleic acids are DNA and RNA.147. Deoxyribonucleic Acid (DNA) = contains information that determines the characteristics of an organism and directs its cell actvities.148. Ribonucleic Acid (RNA) = stores and transfers information from DNA that is essential for the manufacturing of proteins.

149. Some RNA molecules act as enzymes.

150. Both DNA and RNA are polymers, composed of thousands of linked monomers called nucleotides.150. Each nucleotide is made of three main components: a phosphate group, a five-carbon sugar, and a ring-shaped nitrogenous base.

End of unit 1