This document provides an overview of topics related to science experiments and the scientific method. It discusses identifying common lab equipment, formulating hypotheses through observation and inference, measuring variables like temperature, mass and volume, the importance of controls and variables in experiments, techniques for separating mixtures, cell structures, classifying living and nonliving things, types of forces, and components of the Earth and solar system. The document is intended as a revision guide for a 7th grade science class.

1. Revision for Essa
Year 7

2. Working as a scientist
• Identify common lab equipment
• Hypothesising, observing, inferring and
concluding
• Using thermometers
• Format for report writing
• Measuring mass and volume
• Fair testing (controls and variables)

3. Common lab equipment

4. Common lab equipment

5. Hypothesising, observing, inferring &
concluding
• Observing – things or events that you notice.
Eg. footprint, smell of perfume, sound
• You infer something when you use your
observation AND previous knowledge to
explain something
• Hypothesis – educated guess
• Conclusion – final outcome of an investigation

6. Using thermometers
• A thermometer is used to measure
temperature in degrees Celsius (˚C)
• When reading a thermometer you must have
your eyes level with the top of the of the
column (of mercury or alcohol).

7. Using thermometers

8. Format for report writing
• Aim: A short statement about what you are
trying to find out. Must start with the word
TO.
Eg. To determine the battery brand which will
last the longest in a clock radio.
• Hypothesis: Your best educated guess of what
you think you will discover. DO NOT USE THE
WORDS ‘I THINK’ OR ‘I RECKON’.
Eg. Duracell batteries will last the longest in a
clock radio.

9. • Materials: A list of all the equipment/chemicals
to be used. (This is sometimes called apparatus).
• Method: A set of steps outlining how to do the
experiment.
Eg. 1. Pour 100ml of water into a 250ml beaker
2. …..
• Results and observations: a presentation of your
data – this usually includes a table and a graph.
• Discussion: An explanation of your results.
• Conclusion: A brief account of what you found
out. Your conclusion should answer your aim.
Eg. Everlast batteries lasted the longest in a clock
radio.

10. Measuring mass and volume
• Mass = how much matter there is an object or
substance. The standard unit of mass is the
kilogram (kg).
• We use a triple balance beam to measure
mass.

11. Measuring mass and volume
• Volume is a measure of the amount of space
that an object or substance occupies. The
standard unit of volume for liquids is the litre
(L).
• To measure volume we use calibrated
glassware (measuring cylinder, pipette).

12. Measuring mass and volume

13. Measuring mass and volume

14. Fair testing (controls and variables)
• In a fair test all conditions (variables) except
the one being tested should be the same.
• Independent variable: The ONE thing you
change
• Dependent variable: The thing you measure
(eg height, weight, time)
• Controlled variables: everything else that must
remain constant.

15. Separating mixtures
• Terms: solution, solute, solvent, dissolve,
soluble, insoluble, concentrated, dilute,
saturated, sediment/precipitate.
• Separation techniques: crystallisation,
evaporation, filtration, decanting, distillation,
centrifuging, chromatography

16. Key terms
• Solution: a mixture of one substance dissolved in
another.
• Solvent: The substances in which a chemical can
dissolve (usually the liquid).
• Solute: The substance that dissolves (usually the
solid).
FOR YOU TO DO:
• What is the solute and solvent in the following:
milo, cup of coffee, swimming pool water, sea
water?

17. Key terms
• Soluble: substances which dissolve in a liquid.
• Insoluble: substances which do not dissolve in
a solvent.
• Concentrated: more solute is dissolved in the
solvent.
• Dilute: less solute is dissolved in the solvent.
THINK OF CORDIAL: The more cordial you add,
the more concentrated your drink is!

18. Key terms
• Saturated: When no more solute can be
dissolved in a liquid. Think of your clothes
being saturated – you cant get any more wet!
• Sediment: particles that do not mix and settle
to the bottom (like sand in water)
• Suspension: when the insoluble substance is
dispersed (spread) throughout the liquid,
making it cloudy

19. Separation techniques
• Evaporation: when one substance is heated
and evaporates. Salt and water.
• Crystallisation: separating sugar from water.
• Filtration: uses filter paper to separate
insoluble substances from soluble substances.

20. Separation techniques
• Distillation: Separates based on differing
boiling points.

21. Separation techniques
• Decanting: Separates a liquid and a sediment
– by allowing the sediment to settle to the
bottom of the container and the liquid is
poured off the top.

22. Separation techniques
• Centrifuging: Spinning a mixture quickly –
forcing the heavier substances to the sides.
(eg washing machine)
• Separating funnel: an apparatus used to
separate 2 liquids that do not mix (eg oil and
water)

23. Separation techniques
• Chromatography: paints, inks and dyes are
often mixtures of substances that have
different colours – separating these colours
out is chromatography.

24. Cells
• Microscopes (light and electron, monocular and stereo)
• Parts of a microscope
• How to use a microscope
• Calculating total magnification
• Rules for sketching specimens
• Staining specimens
• Cells: look at plant and animal cells
• Basic organelles: cell wall, cell membrane, nucleus,
vacuole, chloroplast, mitochondria, cytoplasm
• Unicellular vs multicellular organisms

25. Microscopes
• Light microscope: uses light rays to see an
image.
• Electron microscope: uses electrons to see an
image.
We use light microscopes at school!
• Monocular microscope: you use only one eye.
• Stereo microscope: you use both eyes.

26. Microscopes

27. Calculating total magnification
• To calculate the total magnification, you must
multiply the magnification of your eyepiece
lens and the objective lens.
Eyepiece lens Objective lens Magnification
5x 5x 25 x
5x 10 x
10 x 100 x
40 x 400 x

28. Rules for sketching
• Use a sharp pencil
• Draw only the lines you see
• Your diagram should take up about a third of
the page
• Record the total magnification
• State the name of the specimen and the date
observed
• Label what you can

29. Staining specimens
• Many specimens are colourless when viewed
down a microscope, so specimens are often
stained (or coloured) to make them easier to
see.

30. Cells – plant and animal
• All living things are made of cells.
• The tiny ‘organs’ of a cell are called the
organelles.
• Plant cells have different organelles to animals
cells.

31. Cell organelles
• Nucleus: control centre of cell
• Cell membrane: controls what goes into and
comes out of cell.
• Cytoplasm: where chemical reactions take
place.
• Cell wall: protection, support and shape.
• Mitochondria: supplies energy.
• Chloroplasts: photosynthesis.
• Vacuole: large cavity (hole) storing water and
other substances.

32. Plants cells vs animal cells

33. Plants cells vs animal cells

34. Unicellular vs multicellular
• Some organisms are made up of a single cell –
they are described as unicellular.
• Multicellular organisms are made up of many
cells with different types of cells doing
different jobs.
• What are some of the cells making up
humans?

35. Solids, liquids and gases
• What is matter/states of matter
• What is volume, how can we measure volume
• Particle model
• Changing states: melting, freezing, evaporation/
boiling, condensation, sublimation,
• Water cycle: cloud and fog
• Convection, conduction, radiation

36. What is matter/states of matter
• Matter is anything with mass and volume.
• Matter can exist in 3 states: solid, liquid and
gas.
• Water is a liquid. What is the name of the
solid and gas forms of water?

37. States of matter
• The different states of matter have different
properties.
Substance State Can the shape Does it take up Can it be
changed easily? space? compressed?
Ice Solid
Water Liquid
Air Gas

38. Volume
• The amount of space taken up by a solid,
liquid or gas is called its volume.
• The volume of liquids is measured in litres or
millilitres.
• The volume of solids are measured in cubic
metres or cubic centimetres.
• How can you measure the volume of an
irregular shaped rock?

39. Particle model
There are 4 parts to the particle model:
• All substances are made of tiny particles
• The particles are attracted towards each other
and surrounding particles
• The particles are always moving or vibrating.
• The hotter the substance is, the more energy
the particles contain and the faster they
move!

40. Balloon experiment

41. Changing states

42. The water cycle
• Cloud: When water vapour becomes cold
enough it condenses to form clouds.
• Fog: Clouds close to the ground.

43. Convection, conduction & radiation

44. Classification
• Living, nonliving, dead
• Dichotomous keys
• 5 vertebrate groups

45. Classification
• Classify means to sort into groups.
• Taxonomy is the science of classifying
organisms.
• One feature that can be used in forming
groups is whether something is living, non
living (was never alive) or dead.
• Sort the following: sun, leaf, bird, rose, water,
wooden table.

46. Dichotomous keys
• There are only 2 choices at each branch.

47. Vertebrate groups
• Vertebrates: animals which have internal
skeletons or backbones.
• Invertebrates: animals which have an external
skeleton or no skeleton.
• 5 vertebrate groups: mammals, aves, reptiles,
amphibia, fish.

49. Forces
• Speed
• Types of forces: gravity, magnetic, electrostatic
• Contact and non-contact forces, buoyancy,
friction

50. Speed
• Speed is a measure of how quickly distance is
covered.
• Speed: distance time
• Units: km/hr, m/sec, cm/min…..

51. Types of forces
• Contact forces: require contact (eg friction)
• Non-contact forces: no contact is required
between objects (eg magnetism)
• Gravity: pull towards Earth
• Buoyancy: upwards push of object while it is
floating
• Friction: force applied to the surface of an
object when it moves against the surface of
another object

52. The Earth and Our Solar System
• Earths structure
• Importance of gases in atmosphere
(greenhouse and ozone gases)
• Night and day, seasons
• Major features of universe (galaxies, stars,
nebulae, solar systems)