San Francisco de Paula, Science Department.
  • Department Home page
    • The International Baccalaureate
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  • MYP Year 6
    • Yr 6 Syllabus & Assessment
    • Contents >
      • Unit 1: Introduction to investigation >
        • How to write Lab Reports
      • Unit 2: Living things
      • Unit 3: Classification of living things
      • Unit 4: Fungi, Protists and Bacteria
      • Unit 5: Nutrition I
    • Laboratory and Tasks
  • MYP Year 7
    • Yr 7 Syllabus & Assessment
    • Contents >
      • 7º PAI en español
      • Unit 1 - What do scientists do? >
        • How to write a lab report
        • SI Units
      • Unit 2 - The Earth in the Universe
      • Unit 3: How can we study living things >
        • Unit 3a - Living things
        • Unit 3b - The Diversity of Life >
          • Monera
          • Protists
          • Fungi
          • The Plant Kingdom
          • The Animal Kingdom
      • Unit 4 - Ecosystems & Biodiversity
      • Unit 5: The systems of the Earth >
        • Unit 5a - The Geosphere and the Atmosphere
        • Unit 5b - The hydrosphere and the Biosphere
      • Unit 6: Our changing home >
        • Unit 6a: Internal Geodynamics
        • Unit 6b: External Geodynamics
    • Laboratory & Tasks
  • MYP Year 8
    • Yr8 Syllabus & Assessment
    • Contents >
      • Units 1, 2 and 3 - Measuring Matters >
        • Unit 1 Physical quantities and Scientific Activity >
          • Converting Units
        • Unit 2 Matter and its Properties
        • Unit 3 Pure Substances and Mixtures >
          • Concentration and units (g/L, % mass)
      • Units 4 and 5 - Chemical Cooking >
        • Models of the Atom
        • Electronic structure of matter.
        • Periodic table (distribution of elements).
        • Chemical formulation
        • Molecular mass
        • Moles
        • Types of reactions
        • Lavoisier's law: Balancing of equations
        • Reaction rates: Factors that affect the speed of a reaction
      • Units 6, 7 and 8 - Move It! >
        • Unit 6 - Motion (URM)
        • Unit 6 - Motion (UARM)
        • Unit 7 - Forces and Mass
        • Unit 8 - Energy and Transformations
    • Laboratory & Tasks >
      • How to write a lab report
  • MYP Year 9
    • Yr9 Syllabus & Assessment
    • Contents >
      • Unit 1 - General organization of the human body, health and illness >
        • Human cells: levels of organisation
        • Health and types of diseases
        • Preventing diseases
        • The Immune System
        • Transplants
        • Addictive substances and associated substances
        • Complete Unit 1
      • Unit 2 - Nutrition >
        • Nutrition and nutrients
        • The Mediterranean diet
        • The anatomy and physiology of the digestive system
        • The anatomy and physiology of the circulatory system >
          • Revision quizzes
        • The anatomy and physiology of the respiratory system
        • The anatomy and physiology of the excretory system
        • Nutrition Documentaries
      • Unit 3 - Interaction and Coordination >
        • The function and anatomy of the nervous system
        • The endocrine system
      • Unit 4 - The reproductive system >
        • Anatomy and physiology of the human reproductive system.
        • Gametogenesis
        • Menstrual cycle
        • Fertilization
        • Infertility, contraception and STDs
      • Unit 5 - Genetics >
        • DNA and genetic modification
        • Cells and Inheritance
        • MORE ON MITOSIS VS MEIOSIS
        • Mendelian genetics
      • Unit 6 - Evolution >
        • Evolutionary theories
        • Evolution Simulators
      • EXTRA Unit 7 - Ecology and the environment >
        • Ecology
    • Laboratory & Tasks
  • MYP Year 10
    • Yr10 Syllabus
    • Contents >
      • Unit 0 - Formulation
      • Unit 1 - Scientific Activity
      • Unit 2 - Kinetic theory
      • The Atmosphere
      • Unit 3 - Mixtures and pures substances: Colligative properties
      • Unit 4 - The structure of matter
      • Unit 5 - Stoichiometry
      • Unit 6 - Redox Reactions
      • Unit 7 - Movement
      • Unit 8 - Forces
      • Unit 9 - Electricity
      • Unit 10 - Energy
    • Revision
    • Assessments and Lab Sessionss >
      • Assessments >
        • Criterion D - Water crisis
      • Session 1 - Paper balls
      • Sessions 2 - Properties of substances
      • Session 3 - Preparing a Schlenk tube
      • Session 4 - Gas constant
      • Session 5 - Colligative properties
      • Session 6 - Job´s method
      • Session 7 - Redox titration
      • Session 8 - UARM
      • Session 9 - Hooke´s Law
    • PISA questions
  • DP Biology SL
    • Contents >
      • Topic 1: Cell biology >
        • 1.1 Introduction to cells
        • 1.2 Ultrastructure of cells
        • 1.3 Membrane structure
        • 1.4 Membrane transport
        • 1.5 The origin of cells
        • 1.6 Cell division
      • Topic 2: Molecular biology >
        • 2.1 Molecules to metabolism
        • 2.2 Water
        • 2.3 Carbohydrates and lipids
        • 2.4 Proteins
        • 2.5 Enzymes
        • 2.6 Structure of DNA and RNA
        • 2.7 DNA replication, transcription and translation
        • 2.8 Cell respiration
        • 2.9 Photosynthesis
      • Topic 3: Genetics >
        • 3.1 Genes
        • 3.2 Chromosomes
        • 3.3 Meiosis
        • 3.4 Inheritance
        • 3.5 Genetic modification and biotechnology
      • Topic 4: Ecology >
        • 4.1 Species, communities and ecosystems
        • 4.2 Energy flow
        • 4.3 Carbon cycling
        • 4.4 Climate change
      • C: Ecology and conservation >
        • C.1 Species and communities
        • C.2 Communities and ecosystems
        • C.3 Impacts of humans on ecosystems
        • C.4 Conservation of biodiversity
      • Topic 5: Evolution and biodiversity >
        • 5.1 Evidence for evolution
        • 5.2 Natural selection
        • 5.3 Classification of biodiversity
        • 5.4 Cladistics
      • Topic 6: Human physiology >
        • 6.1 Digestion and absorption
        • 6.2 The blood system
        • 6.3 Defence against infectious disease
        • 6.4 Gas exchange
        • 6.5 Neurons and synapses
        • 6.6 Hormones, homeostasis and reproduction
    • Labs >
      • Statistical analysis
    • Previous to 2015 >
      • Topic 1: Statistical analysis
      • Topic 2: Cells >
        • 2.1 Cell theory
        • 2.2 Prokaryotic cells
        • 2.3 Eukaryotic cells
        • 2.4 Membranes
        • 2.5 Cell division
      • Option F: Microbes and biotechnology >
        • F1 Diversity of microbes
        • F2 Microbes and the environment
        • F3 Microbes and biotechnology
        • F4 Microbes and food production
      • Topic 5: Ecology and evolution >
        • 5.1 Communities and ecosystems
        • 5.2 The greenhouse effect
        • 5.3 Populations
        • 5.4 Evolution
        • 5.5 Classification
      • Option D: Evolution >
        • D1 Origin of life on Earth
        • D2 Species and speciation
        • D3 Human evolution
      • Topic 3: The chemistry of life >
        • 3.1 Chemical elements and water
        • 3.2 Carbohydrates, lipids and proteins
        • 3.3 DNA structure
        • 3.4 DNA replication
        • 3.5 Transcription and translation
        • 3.6 Enzymes
        • 3.7 Cell respiration
        • 3.8 Photosynthesis
        • TO DELETE
      • Topic 4: Genetics >
        • 4.1 Chromosomes, genes, alleles and mutations
        • 4.2 Meiosis
        • 4.3 Theoretical genetics
        • 4.4 Genetic engineering and biotechnology
      • Topic 6: Human health and physiology >
        • 6.1 Digestion
        • 6.2 The transport system
        • 6.3 Defence against infectious disease
        • 6.4 Gas exchange
        • 6.5 Nerves, hormones and homeostasis
        • 6.6 Reproduction
    • Tasks >
      • Databases
    • Documents
    • DP Biology Resources
    • Interesting links
  • Biología 12º
    • Bloque 1. Bioquímica
    • Bloque 2. Biología celular
    • Bloque 3. Genética y evolución
    • Bloque 4. Microbiología y biotecnología
    • Bloque 5. Inmunología
  • IB Biología NS
  • IB Chemistry HL
    • Contents >
      • Year 1 >
        • Topic 0 - Formulation
        • Topic 1 - Stoichiometric relationships
        • Topic 2 and 12 - Atomic structure
        • Topic 3 and 13 - Periodicity
        • Topic 4 and 14 - Chemical structure and bonding
        • Topic 5 and 15 - Energetics
        • Topic 10 and 20 - Organic chemistry
      • Year 2 >
        • Topic 6 and 16 - Chemical kinetics
        • Topic 7 and 17 - Equilibrium
        • Topic 8 and 18 - Acids and bases
        • Topic 9 and 19 - Redox processes
        • Topic 11 and 21 - Measurement and data processing
        • Option D - Medicinal chemistry
    • Lab work >
      • SFP Campus lab reports
      • Internal assessment structure
      • Internal Assessment examples
    • Nature of science
    • General revision
    • Selectividad
    • General information
    • Extended Essay
  • Other resources for students
    • Science Fair
    • Science essays >
      • How to Reference
    • Chemical formulation
    • Laboratory >
      • How to write a lab report
      • Microscopy
      • Excel for graphs and calculations >
        • Calculate the mean and SD
        • Drawing graphs
        • Add error bars to excel graphs
      • Lab videos!
    • Further Reading >
      • Women In Science
      • Infographics
    • Proyecto integrado
  • Department Home page
    • The International Baccalaureate
    • Conceptual learning
    • How will I be assessed?
    • Primary Science Club
    • Science Activities Noticeboard
  • MYP Year 6
    • Yr 6 Syllabus & Assessment
    • Contents >
      • Unit 1: Introduction to investigation >
        • How to write Lab Reports
      • Unit 2: Living things
      • Unit 3: Classification of living things
      • Unit 4: Fungi, Protists and Bacteria
      • Unit 5: Nutrition I
    • Laboratory and Tasks
  • MYP Year 7
    • Yr 7 Syllabus & Assessment
    • Contents >
      • 7º PAI en español
      • Unit 1 - What do scientists do? >
        • How to write a lab report
        • SI Units
      • Unit 2 - The Earth in the Universe
      • Unit 3: How can we study living things >
        • Unit 3a - Living things
        • Unit 3b - The Diversity of Life >
          • Monera
          • Protists
          • Fungi
          • The Plant Kingdom
          • The Animal Kingdom
      • Unit 4 - Ecosystems & Biodiversity
      • Unit 5: The systems of the Earth >
        • Unit 5a - The Geosphere and the Atmosphere
        • Unit 5b - The hydrosphere and the Biosphere
      • Unit 6: Our changing home >
        • Unit 6a: Internal Geodynamics
        • Unit 6b: External Geodynamics
    • Laboratory & Tasks
  • MYP Year 8
    • Yr8 Syllabus & Assessment
    • Contents >
      • Units 1, 2 and 3 - Measuring Matters >
        • Unit 1 Physical quantities and Scientific Activity >
          • Converting Units
        • Unit 2 Matter and its Properties
        • Unit 3 Pure Substances and Mixtures >
          • Concentration and units (g/L, % mass)
      • Units 4 and 5 - Chemical Cooking >
        • Models of the Atom
        • Electronic structure of matter.
        • Periodic table (distribution of elements).
        • Chemical formulation
        • Molecular mass
        • Moles
        • Types of reactions
        • Lavoisier's law: Balancing of equations
        • Reaction rates: Factors that affect the speed of a reaction
      • Units 6, 7 and 8 - Move It! >
        • Unit 6 - Motion (URM)
        • Unit 6 - Motion (UARM)
        • Unit 7 - Forces and Mass
        • Unit 8 - Energy and Transformations
    • Laboratory & Tasks >
      • How to write a lab report
  • MYP Year 9
    • Yr9 Syllabus & Assessment
    • Contents >
      • Unit 1 - General organization of the human body, health and illness >
        • Human cells: levels of organisation
        • Health and types of diseases
        • Preventing diseases
        • The Immune System
        • Transplants
        • Addictive substances and associated substances
        • Complete Unit 1
      • Unit 2 - Nutrition >
        • Nutrition and nutrients
        • The Mediterranean diet
        • The anatomy and physiology of the digestive system
        • The anatomy and physiology of the circulatory system >
          • Revision quizzes
        • The anatomy and physiology of the respiratory system
        • The anatomy and physiology of the excretory system
        • Nutrition Documentaries
      • Unit 3 - Interaction and Coordination >
        • The function and anatomy of the nervous system
        • The endocrine system
      • Unit 4 - The reproductive system >
        • Anatomy and physiology of the human reproductive system.
        • Gametogenesis
        • Menstrual cycle
        • Fertilization
        • Infertility, contraception and STDs
      • Unit 5 - Genetics >
        • DNA and genetic modification
        • Cells and Inheritance
        • MORE ON MITOSIS VS MEIOSIS
        • Mendelian genetics
      • Unit 6 - Evolution >
        • Evolutionary theories
        • Evolution Simulators
      • EXTRA Unit 7 - Ecology and the environment >
        • Ecology
    • Laboratory & Tasks
  • MYP Year 10
    • Yr10 Syllabus
    • Contents >
      • Unit 0 - Formulation
      • Unit 1 - Scientific Activity
      • Unit 2 - Kinetic theory
      • The Atmosphere
      • Unit 3 - Mixtures and pures substances: Colligative properties
      • Unit 4 - The structure of matter
      • Unit 5 - Stoichiometry
      • Unit 6 - Redox Reactions
      • Unit 7 - Movement
      • Unit 8 - Forces
      • Unit 9 - Electricity
      • Unit 10 - Energy
    • Revision
    • Assessments and Lab Sessionss >
      • Assessments >
        • Criterion D - Water crisis
      • Session 1 - Paper balls
      • Sessions 2 - Properties of substances
      • Session 3 - Preparing a Schlenk tube
      • Session 4 - Gas constant
      • Session 5 - Colligative properties
      • Session 6 - Job´s method
      • Session 7 - Redox titration
      • Session 8 - UARM
      • Session 9 - Hooke´s Law
    • PISA questions
  • DP Biology SL
    • Contents >
      • Topic 1: Cell biology >
        • 1.1 Introduction to cells
        • 1.2 Ultrastructure of cells
        • 1.3 Membrane structure
        • 1.4 Membrane transport
        • 1.5 The origin of cells
        • 1.6 Cell division
      • Topic 2: Molecular biology >
        • 2.1 Molecules to metabolism
        • 2.2 Water
        • 2.3 Carbohydrates and lipids
        • 2.4 Proteins
        • 2.5 Enzymes
        • 2.6 Structure of DNA and RNA
        • 2.7 DNA replication, transcription and translation
        • 2.8 Cell respiration
        • 2.9 Photosynthesis
      • Topic 3: Genetics >
        • 3.1 Genes
        • 3.2 Chromosomes
        • 3.3 Meiosis
        • 3.4 Inheritance
        • 3.5 Genetic modification and biotechnology
      • Topic 4: Ecology >
        • 4.1 Species, communities and ecosystems
        • 4.2 Energy flow
        • 4.3 Carbon cycling
        • 4.4 Climate change
      • C: Ecology and conservation >
        • C.1 Species and communities
        • C.2 Communities and ecosystems
        • C.3 Impacts of humans on ecosystems
        • C.4 Conservation of biodiversity
      • Topic 5: Evolution and biodiversity >
        • 5.1 Evidence for evolution
        • 5.2 Natural selection
        • 5.3 Classification of biodiversity
        • 5.4 Cladistics
      • Topic 6: Human physiology >
        • 6.1 Digestion and absorption
        • 6.2 The blood system
        • 6.3 Defence against infectious disease
        • 6.4 Gas exchange
        • 6.5 Neurons and synapses
        • 6.6 Hormones, homeostasis and reproduction
    • Labs >
      • Statistical analysis
    • Previous to 2015 >
      • Topic 1: Statistical analysis
      • Topic 2: Cells >
        • 2.1 Cell theory
        • 2.2 Prokaryotic cells
        • 2.3 Eukaryotic cells
        • 2.4 Membranes
        • 2.5 Cell division
      • Option F: Microbes and biotechnology >
        • F1 Diversity of microbes
        • F2 Microbes and the environment
        • F3 Microbes and biotechnology
        • F4 Microbes and food production
      • Topic 5: Ecology and evolution >
        • 5.1 Communities and ecosystems
        • 5.2 The greenhouse effect
        • 5.3 Populations
        • 5.4 Evolution
        • 5.5 Classification
      • Option D: Evolution >
        • D1 Origin of life on Earth
        • D2 Species and speciation
        • D3 Human evolution
      • Topic 3: The chemistry of life >
        • 3.1 Chemical elements and water
        • 3.2 Carbohydrates, lipids and proteins
        • 3.3 DNA structure
        • 3.4 DNA replication
        • 3.5 Transcription and translation
        • 3.6 Enzymes
        • 3.7 Cell respiration
        • 3.8 Photosynthesis
        • TO DELETE
      • Topic 4: Genetics >
        • 4.1 Chromosomes, genes, alleles and mutations
        • 4.2 Meiosis
        • 4.3 Theoretical genetics
        • 4.4 Genetic engineering and biotechnology
      • Topic 6: Human health and physiology >
        • 6.1 Digestion
        • 6.2 The transport system
        • 6.3 Defence against infectious disease
        • 6.4 Gas exchange
        • 6.5 Nerves, hormones and homeostasis
        • 6.6 Reproduction
    • Tasks >
      • Databases
    • Documents
    • DP Biology Resources
    • Interesting links
  • Biología 12º
    • Bloque 1. Bioquímica
    • Bloque 2. Biología celular
    • Bloque 3. Genética y evolución
    • Bloque 4. Microbiología y biotecnología
    • Bloque 5. Inmunología
  • IB Biología NS
  • IB Chemistry HL
    • Contents >
      • Year 1 >
        • Topic 0 - Formulation
        • Topic 1 - Stoichiometric relationships
        • Topic 2 and 12 - Atomic structure
        • Topic 3 and 13 - Periodicity
        • Topic 4 and 14 - Chemical structure and bonding
        • Topic 5 and 15 - Energetics
        • Topic 10 and 20 - Organic chemistry
      • Year 2 >
        • Topic 6 and 16 - Chemical kinetics
        • Topic 7 and 17 - Equilibrium
        • Topic 8 and 18 - Acids and bases
        • Topic 9 and 19 - Redox processes
        • Topic 11 and 21 - Measurement and data processing
        • Option D - Medicinal chemistry
    • Lab work >
      • SFP Campus lab reports
      • Internal assessment structure
      • Internal Assessment examples
    • Nature of science
    • General revision
    • Selectividad
    • General information
    • Extended Essay
  • Other resources for students
    • Science Fair
    • Science essays >
      • How to Reference
    • Chemical formulation
    • Laboratory >
      • How to write a lab report
      • Microscopy
      • Excel for graphs and calculations >
        • Calculate the mean and SD
        • Drawing graphs
        • Add error bars to excel graphs
      • Lab videos!
    • Further Reading >
      • Women In Science
      • Infographics
    • Proyecto integrado
San Francisco de Paula, Science Department.

Unit 1 - Scientific activity

Key concept - Systems - How do we quantify magnitudes in science?

Related concepts - Patterns and models - How can we use scientific conventions to better model the world around us?

Global concept - Scientific innovation and technology  - How has science progressed in its ability to describe the physical world?
Unit 1 KEYWORDS
  • Magnitude
  • Vector
  • Quantity
  • Fundamental (base)
  • Derived
  • Lowercase
  • Uppercase
  • Precision
  • Error
  • Systematic
  • Random
  • Calibration
  • Parallax
  • Repeats
  • Average (mean)
  • Accurate
  • Inaccurate
  • Positive linear
  • Negative linear
  • Exponential
  • Inverse
Task guide
The tasks and questions on the Weebly will be coloured to represent the different style of questions that you will find in your exams. The task should be completed in your "Physics and Chemistry" GoogleDrive document (PSD).

Green -   Explaining scientific knowledge
Orange - Applying scientific knowledge and understanding
Red -     Analysing and evaluating information

There will also be "extension" tasks for students who finish tasks quickly! Also look out for links to interactive resources and videos.

UNIT ANSWERS-  LINK

1.1 Scalar magnitudes and vectors

Definition: Physical magnitudes are properties of objects that can be measured by comparison with a standard unit.
  • A scalar magnitude is expressed with a number and the associated unit e.g. a time of 3 minutes.
  • A vector is a quantity that possesses both a scalar magnitude but with a direction e.g. a car driving east with a velocity of 35 m/s.
Note: A force of 5 N is not a vector unless a direction is given as well.
Picture
(Quenqua, 2012)
This content will be covered in greater detail in the 2nd and 3rd trimester.

1.2 SI Units

Watch the following video that highlights some of the topics we will cover in this unit.
In 1960 the Système International d´Unités (SI) was agreed upon to enhance scientific communication.

The table on the left (Marshscience.blogspot.com.es, 2014) shows the 7 fundamental units agreed upon by this convention.
Picture
Picture
Note: Symbols for units are always in lowercase unless the unit is named after somebody, in which case it is in UPPERCASE.
Derived units are units that contain a combination of fundamental units to describe quantities such as acceleration and electrical resistance. 
The common units for energy are joules (J). However, if we look at the SI units for joules you can see they are a bit more complicated! -->
Picture
(Spiff.rit.edu, 2015)

1.3 Writing units

There are a number of conventions that we must follow when writing units:
  • Leave a space between the number and symbol of the unit -->  25 kg NOT 25kg
  • Units written as words are always lowercase --> 4 newtons NOT 4 Newtons
  • Decimals are always written with a point/comma below --> 19.6 or 19,6 NOT 19`6
Task 1a: Identify which of the following units are written incorrectly and rewrite them. in your PCD.
  • 1000Mm
  • 5 Candela
  • 25.06 ccd
  • 94 K
  • 74888 m seconds
  • 0.004Moles
  • 20 hm
  • 12 µ m

Which other units exist for temperature?


What relevance do the 2 following objects have in this topic? Click on the photos to find out more.
Picture
(EETimes, 2015)
Imagen

Picture
Lab session 1 - Paper balls
The first lab session will be related to the following content on making measurements and presenting data.
1._paper_balls__2__2018-2019_.docx
File Size: 40 kb
File Type: docx
Download File

Picture

1.4 Making measurements - Precision

Precision: Which of these pieces of equipment is the most precise?
Picture
(Denovoverseas.com, 2015)
Picture
(Sites.google.com, 2015)
Picture
(Amazon.com, 2015)
The answer is the measuring cylinder because it allows us to measure to the smallest division of the unit. The bowl allows us to measure to the nearest 500 ml, the beaker to the nearest 25 ml and the measuring cylinder to the nearest 1 ml. The precision would be written ± 500 ml, ± 25 ml and ± 1 ml respectively.
Task 1b:
  • Find and paste 2 different images into your PCD showing equipment with different precision used to measure: time; mass and volume (with different equipment to the ones shown above!). Write the precision for each one.
An example for length has been done below (Fabricating and Metalworking, 2013).
  • Which is the most precise piece of equipment in the chemistry lab?
Picture
This ruler has a precision of ± 0.1 cm
Picture
This Vernier Caliper has a precision of ± 0.02 cm
  • Write a procedure to make a 0.5 M solution of NaOH..

1.5 Making measurements - Error

Experimental measurements will always be affected by error. The two types of error that can occur in an experiment are systematic and random.
Systematic errors - arise from a problem in the experimental set-up that results in the measured values always deviating from the “true” value in the same direction, that is, always higher or always lower. For example, if a scale is incorrectly calibrated and always gives a slightly higher reading than it should (calibration error). We can also find systematic error in the incorrect reading of measurements as shown in the second diagram (parallax error). Systematic errors are difficult to identify as the error is always carried in the same direction so it is not obvious that it is occuring.
Picture
Calibration error could be present in the use of a balance - (220-3NM, 2015)
Picture
Parralax error - (Eni Generalic, 2015)
Random errors – are caused by unpredictable changes in the equipment or conditions of an experiment. They can lead to measurements being above or below the “true” value. A random change in the current flow in an electrical circuit would be an example. Random errors can be reduced with the use of more precise measuring equipment or its effect minimized through repeat measurements so that their effect is minimised when an average is taken.
Picture
An accurate result is a result that is close to the true value. This is done by minimising systematic and random errors.
Human error
Now that you are in Year 10 it is assumed that you are able to carry out simple laboratory tasks accurately. Therefore, we do not consider human error when writing a report!

Spilling a solution on the floor is not an acceptable error!
Picture
(Rourke, 2013)
Hint: When writing an evaluation of an experiment, look at each step in the procedure and consider the possibility of systematic and random error in each step.
Task 1c i: Make a list of 3 common random errors and 3 common systematic errors that could occur in an experiment.

Task 1c ii - Read the following procedure and explain all the possible systematic and random errors that could be present.
Preparing 500 ml of a 1 M solution of NaOH
  1. Weigh 20 g of NaOH powder in a weighing boat using a simple scale.
  2. Fill a large beaker with 500 ml distilled water.
  3. Add the NaOH to the water and stir for 30 seconds.
Identify any weaknesses in the evaluation and suggest at least 3 improvements that could be made.

1.6 Significant figures

Significant figures (sig figs) are the figures in a number that allow us to appreciate the precision in a measurement. 

For example: In a measurement of 7.3 mm, which has 2 sig figs, the final sig fig tells us the unit division in which the error is found. In this case the last sig fig is the 3 (tenths of a millimeter) so the precision of the measurement is ± 0.1 mm.
Rules for determining significant figures:
  • Figures that are not zero are always significant --> 194.78
  • All figures to the right of the decimal point are significant (even zero) --> 23.40
  • Zeros at the beginning of a number are not significant --> 0.00520       0.82
  • Zeros at the end of a number without a decimal point are not significant --> 35400             105000300

For the final rule, it can be difficult when given data that is not yours to appreciate the number of significant figures so we often represent the data using scientific notation...

1.7 Scientific notation

When dealing with very small or very large numbers it is preferable to use scientific notation. This must be in a format with only 1 figure before the decimal point and then a positive or negative power of 10. 
Picture
(Passy's World of Mathematics, 2013)
Task 1d: How many significant figures are found in the following numbers?
  1. 100
  2. 2 . 82
  3. 450000 . 2
  4. 0.000072
  5. 4.00 x 10^5
Write the following in scientific notation:
  1. 1001
  2. 0 . 000087
  3. 98 . 1
  4. 267544
  5. 54 . 54

1.8 Using SFs and DPs in calculations

When carrying out calculations with experimentally retrieved data we must handle the number of sig figs/decimal places carefully to ensure we do not lose or gain unnecessary accuracy in the final result. There are 3 simple rules to follow.

1.     If you are multiplying or dividing values then we consider the number of sig figs. The lowest number of significant figures used in the calculation should be given in the result.

2.     If you are adding or subtracting values then we consider the number of decimal places. The lowest number of decimal places used in the calculation should be given in the result.

3.     Numbers that are NOT from your data can be ignored when using the rules above. So when calculating an average from 3 numbers, you may ignore the `3´ that is used to divide them - it is an exact number.

Here are some examples:

4.80 + 2.60 + 1.2 = 8.6     (Lowest number of decimal places is 1)

3.5 x 19.36 = 68    (Lowest number of significant figures is 2)

Calculating an average: (1.68 + 8.52 + 7.31) / 3 = 5.84     (Lowest number of decimal places is 2 as the `3´ can be ignored)

Task 1e: Calculate the answers to these questions taking into account significant figures and decimal places. (Assume all numbers are experimentally obtained)
a.     5.8 + 4.56 + 12 =
b.     0.008 – 0.0456 + 0.9 =
c.     11 x 222 x 333 =
d.     19.30 / 182.3 = 
e.     (4.5 x 10^3) x (18.93 + 2.07) = 
f.      What is the average of these data points – 42.66, 43.810, 43.0



Complete the following online test: http://www.sciencegeek.net/Chemistry/taters/Unit0Sigfigs.htm
Extension:
  1. State the symbols for the following units: milliseconds, gigacandela, nanomol, microkelvin.
  2. Write the following in scientific notation:    450    0.0056    988300200    0.00000000014
  3. Identify the incorrectly written magnitudes and write them correctly: 42 ms,  78kg,  5.32 da cd,   1  cm/s.

1.9 Analysis of data

You will be required to represent data obtained in the lab in a graphical format. Normally a scattergraph with a line of best fit. 
Task 1e: Use Microsft Excel to draw a scattergraph for ONE of the following simple tables of data. For each one include:
  • Labelled axes with units
  • A title (Graph to show...)
  • A line of best fit (línea de tendencia)
  • Describe the shape of the graph
  • Write a 1 sentence conclusion
Picture
Task 1f: Dowload the following table of results from Mr Canning´s paper ball experiment and complete the following tasks:
  1. Complete the mean (average) column and the SD (standard deviation) column
  2. Plot a scatter graph of the surface area v diameter (the mean).
  3. Add error bars using standard deviation.

When finished compare your graph with the answer on the second tab.


Help: Adding standard deviation and error bars
Picture

1.10 Conversion factors

Conversion factors are a very useful way of dealing with unit conversion and also many P+C problems. Watch the video below and try the following
Task 1g: Convert these values using conversion factors:
6 days         into hours
12 mins       into seconds
1825 days   into years

700 dm   into hm
3.7 km    into cm
9 dam     into mm

20 m/s       into   km/h
144 km/h   into   m/s
5 m/s         into   dm/min
6 hm/h      into   m/min
Use the answers to check your accuracy!:
144 h
720 s
5 years

0.7
370000
90000

72
40
3000
10

Class presentation

Picture
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Revision

Practice exam questions
unit_1_practice_questions.docx
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Marshscience.blogspot.com.es,. (2014). Thomas C. Marsh Preparatory Middle School 7th Grade Science!: August 2014. Retrieved 22 July 2015, from http://marshscience.blogspot.com.es/2014_08_01_archive.html

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Quenqua, D. (2012). Wingsuits Let Jumpers Spread Their Wings. Nytimes.com. Retrieved 9 July 2015, from http://www.nytimes.com/2012/12/16/fashion/wingsuits-let-jumpers-spread-their-wings.html?_r=0

Sites.google.com,. (2015). Beaker - BioChem Group. Retrieved 22 July 2015, from https://sites.google.com/a/asu.edu/biochem-group/beaker

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