Skills, Processes and Procedures

Skills, Processes, and Procedures

  • Science is an exciting subject involving experiments and laboratory work.

What is Science?

  • Science involves conducting experiments to find answers to problems.
  • Science is a body of knowledge encompassing various fields:
    • Chemistry: Study of chemicals and their changes.
    • Physics: Study of energy, matter, and movement.
    • Biology: Study of living things.
    • Astronomy: Study of planets, stars, and the universe.
    • Geology: Study of rocks and the Earth.
    • Ecology: Study of interactions between plants, animals, and the environment.

Safety in the Science Room

  • Laboratories can be dangerous; safety rules are crucial.
General Safety
  1. Enter the science room only with a teacher's permission.
  2. Always wear a lab coat and closed-toe, flat shoes.
  3. No running or pushing in the lab.
  4. Keep notebooks neat, tidy, and away from experiments.
  5. Never eat, drink, or chew gum in the laboratory; avoid using laboratory glassware for consumption.
  6. Do not taste or inhale chemicals; wash hands after lab work, especially before eating.
  7. Dispose of waste liquids in sinks or waste bottles, solids in rubbish bins, and broken glass in special bins.
  8. Clean equipment after use and return it to its proper place; clean work benches after experiments.
Heating and Mixing Chemicals
  1. When heating or mixing chemicals, never look inside the flask or beaker.
  2. Do not point test tubes or beakers towards yourself or others; wear safety goggles while heating.
  3. Use the correct method for lighting a Bunsen burner.
  4. Allow heated equipment to cool before handling.
  5. Tie back long hair to keep it away from flames and chemicals.
  6. Keep flammable substances away from open flames.
Accidents
  1. Report all breakages and damage to the teacher.
  2. Wash chemical spills on skin with plenty of running water and seek help from the teacher.
  3. Smother clothing fires with a blanket or coat; never run.

Safety Labels

  • Hazardous chemicals are labeled with symbols to indicate their properties:

    • Poison: Example - Chloroform

    • Flammable: Example - Methylated spirit

    • Corrosive: Example - Caustic soda, Hydrochloric acid

    • Explosive/Combustible: Example - Sodium in Water

    • Material Hazard: Example - Hydrogen (concentrated)

Working in the Laboratory

  • Common equipment includes microscopes and Bunsen burners.
Microscope

  • A microscope magnifies small objects for detailed study.

  • Types of Microscopes:

    • Simple Microscope: Uses one magnifying lens in a tube.
    • Compound Microscope: Uses two lenses (eyepiece and objective) and is commonly used in schools. Focuses light through an object.
    • Stereo/Dissecting Microscope: Used for thicker objects or dissection, observing tissues and organs.

  • Steps for using a microscope:

    • Secure the slide with clips.
    • Reset to low power and store the microscope properly after use.
    • Use fine focus for medium power, adjusting light as needed.
    • Position the lamp and mirror for optimal light.
    • Move the objective AWAY from the stage using coarse focus.
    • Always start with low power.
    • Turn to medium power for more detail.
    • Bring the objective close to the stage while viewing from the side.

  • Specimens must be thin and transparent; mount between a microscope slide and coverslip. Water prevents drying, stains enhance visibility.

  • Preparing a wet mount involves placing the specimen in the center of the slide, adding a drop of water (if needed), adding stain (iodine for animal cells, methylene blue for plant cells), and placing coverslip

  • Microscope care requirements:

    • Carry the microscope with two hands.
    • Store in its box or covered.
    • Clean lenses with special tissue paper only.
    • Ensure all parts are attached and functioning.
Lighting a Bunsen Burner
  • Bunsen burners are common lab equipment.
  1. Attach the rubber tube to the gas outlet.
  2. Close the air hole by turning the collar.
  3. Light the match and hold it over the top of the barrel.
  4. Turn on the gas last.
    * (Yellow "safety flame" is produced when the air hole is closed. It’s not very hot or good for heating).
  5. Open the air hole to mix air with gas for a hotter, pale blue flame used for heating.
  6. Use the yellow safety flame when not heating.
Rules for Heating in Test Tubes:
  1. Never fill the test tube more than one third full.
  2. Always use a test tube holder.
  3. Point the test tube away from yourself and away from others.
  4. Heat the side of the test tube, avoid heating the bottom.
  5. Move the test tube in the flame as you heat it.
Thermometers
  1. Always keep the thermometer in its case unless it is being used. Secure the cap of the case as it is made of glass and can break easily.
  2. Do not shake the thermometer because it is long and can snap easily.
  3. Do not drop it into any container you are using as it could damage the bottom of the container.
  4. Do not leave it at the edge of the bench, it could roll off and break.
  5. Hold it in the middle-never by the bulb as you do not want to measure the temperature of your hand.
  6. Do not use it for stirring liquids.

Laboratory Equipment

  • Equipment includes beakers, burners, flasks, and stands; apparatus refers to the setup of equipment for an experiment.
  • Common Laboratory Equipment:
    • Test tube: For holding and mixing small volumes of liquid.
    • Test tube holder: Used to hold test tubes when they are hot and untouchable.
    • Test tube rack: For holding the test tubes used and not used.
    • Beaker: For holding and heating large volumes of water.
    • Tripod Stand: Used for holding objects above the Bunsen burner. Multipurpose and useful in the lab.
    • Measuring Cylinder: Used for measuring large volume of liquids.
    • Filter Funnel: Used for targeting liquids into any container so they will not be lost or spilled.
    • Gauze Wire: Used for holding objects above the tripod stand
    • Bunsen burner: Used for heating and exposing items to flame.
    • Conical Flask: Used to heat and store chemicals. The bottom is wider than the top so it will heat quicker because of the great surface area exposed to the heat.
    • Triple Beam balance: Used for finding the mass of liquids.
    • Thermometer: Used to take temperature of solids, liquids and gases.
    • Spring Balance: Used to measure the weight of an object by opposing the force of gravity with the force of an extended spring
    • Spatula: Used for moving small amounts of solids from place to place.
    • Stirring rod: Usually used to stir things.
    • Hand lens: Used to magnify an object or make things appear closer
    • Watch Glass: Circular concave glass used for evaporating liquids or holding small samples.

Keeping Records

  • Records include diagrams of equipment and written reports.
Rules for drawing in Science
  1. Always use a pencil (HB or B pencils are good because they rub out easily).
  2. Always use a ruler for straight lines.
  3. Draw outline diagrams – no sketches or perspectives.
  4. Draw the diagram big enough so that it can be seen clearly (a quarter to a whole page depending on the object).
  5. Label the object clearly. Sometimes you need to label parts of the object. Point to these with lines.
  6. Do not colour the diagrams.
Writing Practical Reports
  • Components of a lab report:
    • Title
    • Introduction
    • Aim: Purpose of the experiment.
    • Hypothesis: An informed prediction.
    • Materials: List of equipment and chemicals.
    • Method: Detailed account of the procedure, including a diagram of the setup.
    • Results & Observations: Presentation of data, including observations, calculations, tables, and graphs.
    • Discussion: Explanation of results, difficulties, and suggestions for improvement.
    • Conclusion: Relates to the aim, indicating if the hypothesis was supported or disproved.
    • Bibliography: List of written sources used.
    • Acknowledgements

Measurements

  • Measurements must be consistent, using standard units (metric system in Fiji).
  • Every measurement has two parts: the number and the unit.
  • Prefixes are used to denote very large or small things being measured.
PrefixSymbolMultiply by
megaM10000001 000 000
kilok10001000
hectoh100100
decada1010
decid1/101/10
centic1/1001/100
millim1/10001/1000
microμ1/10000001/1 000 000

  • Volume

    • How much space something takes up.
    • Measured in litres (L) and millilitres (mL).
    • Use beakers and measuring cylinders.
    • Is pulled up where it touches the glass, this is called the meniscus. When you measure volume, always read the scale from the bottom of the meniscus.

  • Length

    • Length is measured in the unit called metres (m)
    • For long distances, kilometers (km) are used
    • For short distances, centimeters (cm) or millimetres (mm) are used
    • Use trundle wheel, metre rule and tape measure.

  • Mass

    • Mass is how much matter is in an object
    • It is measured in the units called grams (g) or kilograms (kg)
    • Tiny masses are measured in milligrams (mg)
    • Use beam balances, spring balances and electronic scales.

  • Time

    • Time is measured in the unit called seconds (s)
    • Other units of time are minutes and hours
    • It is measured with a watch or a clock
    • Use stopwatch

  • Temperature

    • Temperature is measured in the unit called degrees Celsius (ºC)
    • It is measured with a thermometer or a thermistor

Unit 2: Investigating

Making Observations
  • An observation is something you notice using your senses. An inference is a likely explanation of what you observed. A hypothesis is a testable guess at an answer.
  • Some things cannot be tested by experiment such as personal likes and dislikes.
  • A control is the part of a science experiment that acts as a standard by which to compare experimental observations.
  • Before starting an experiment, it is important that you plan what you are going to do. Write it in your notebook. It is important to check with the teacher so that time taken and materials used is not wasted.
Displaying Data
  • Data can be presented in tables or graphs.
Tables
  • Tables consist of rows and columns, used to organize data. Suitable for data that involve both words and numbers.
  • A table should have:
    • a clear and simple title.
    • a set of rows and columns
    • heading for the columns with unit if data have been measured in units
Graphs

  • Graphs should:

    • have a title.
    • fill most of the graph paper.
    • start at 0 on vertical axis (horizontal axis as well if it is part of data).
    • have regular scales.
    • have clearly plotted data points joined with a ruler.
    • have labeled axes with names and units.

  • Different graph types: histogram, bar graph, line graph, and pie chart.

    • Bar graphs: Used to compare data & have labelled axes
    • Line graphs: Used to Show data changes over time & have labelled axes
    • Pie graphs /charts: Used to represent data as portions of a whole. & uses (3.6ºxX(3.6º x X% = Yº)
Fair Testing
  • Experiments should be fair and valid, repeatable by others; control experiments are used for comparison.
  • The variable is what you test, and the control is what you compare it with.
  • Scientific method steps:
    • Observing.
    • Inferring.
    • Hypothesis.
    • Design a fair experiment with a control.
    • Do the experiment and study the results.
    • Form a conclusion to answer the hypothesis.
  • In fair science investigations we:
    • change one variable at a time
    • measure another variable
    • keep all other variables the same.