Science KS3

For Tanglin Trust School Year 8 Science assessments.

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Respiration - The Lungs

  • The lungs are basically two sacks of air.
  • The windpipe is also known as the trachea.
  • Diagram of the lungs:
  • ........................ | Trachea
  • ........................ |
  • ...................( o / \ o ) Bronchus
  • ................(... \ /.. \ /...) Bronchioles
  • ...............(......o- -o......)
  • ..............(........./ \..........)
  • .............(....... o...o..........)
  • o represent alveoli
  • ( or ) represent intercostal muscles
  • Ignore the full stops
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Respiration - Gases that we breath in and out

We breath in:

  • 78% Nitrogen (N2)
  • 21% Oxygen (O2)
  • 0.04% Carbon Dioxide (CO2)
  • 0.02% Water Vapour (H2O)
  • 0.94% Noble Gases

We breath out:

  • 78% Nitrogen
  • 17% Oxygen
  • 3.06% Carbon Dioxide
  • 1% Water Vapour
  • 0.94 Noble Gases
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Respiration - How Gas is Exchanged in the Alveoli

  • Diffusion: particles move from an area of high concentration to an area of lower concentration until they are spread ouy.
  • Flowchart of the respiratory system:

Nose or mouth -> trachea -> bronchi -> bronchioles -> alveoli -> Heart

  • Gas exchange flowchart:

Oxygen in alveoli -> Capillary

Carbon Dioxide in capillary -> Alveoli

  • Spongy formation = more surface area. Means gas exchange happens quicker.
  • Red blood cells carry oxygen from the capillary to the heart to the muscles.
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Mixtures - Elements, Compounds and Mixtures

  • Element - Made up of the same atoms that cannot be broken down into anything simpler
  • Compound - Two or more elements bonded.
  • Mixture - Different atoms mixed together
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Mixtures - Changes in matter

  • Solid to liquid is melting
  • Liquid to gas is evaporation
  • Gas to solid is desublimation
  • Liquid to solid is freezing
  • Gas to liquid is condensation
  • Solid to gas is sublimation
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Forces - What are they?

  • A push, pull or twist that acts on an object.
  • They can change the speed of an object, the direction of the object or the shape of an object.
  • We measure them in newtons.
  • Gravity pulls objects downwards.
  • Air resistance (or drag) acts against anything moving through air.
  • Friction acts against anything moving.
  • Upthrust acts upwards on objects that are afloat.
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Forces - Speed, distance and time

Equation triangle:

Distance

Speed | Time

Speed of a bat: distance divided by time.

Distance of car: speed times time

Time of the run: distance divided by speed.

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Plants - Plant Cells

  • Nucleus contains genetic information
  • Cell wall keeps the shape of the cell
  • Membrane allows certain things to get in or out
  • Vacuole stores things for the plant.
  • Chloroplasts photosyntesis.
    • Photosynthesis: the process by which plants make food for themselves.
  • Cytoplasm prevents the cell from collapsing.

A root hair cell has all these things except for the chloroplasts. They have a root "hair" that absorbs nutrients from the ground.

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Plants - Stoma and Chloroplasts

Chloroplasts contain chlorophyll. This gives the leaf a green colour. Here photosynthesis takes place.

Photosynthesis equation:

Carbon dioxide + water -----------------------> glucose + oxygen

..........................................light

......................................chlorophyll

Stoma are holes in the bottom of the plant. They let gases in and out of the plant.

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Plants - Their food

Plants make glucose as their food. It is necessary to "feed" the plant.

Some plants do not need all this glucose. It gets stored as starch.

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Comments

Chuck Rottingpork

Hello. This may be helpful, it may not be.

Thanks,

Chuck Rottingpork

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