Science

• Types of waves


  • Transverse
  • Longitudinal
• Transverse wave


  • Vibrations of the particles are at right angles to the direction the energy of the wave travels
• Transverse waves


  • Ripples on the surface of the water
  • Vibrations of a guitar string
• Longitudinal wave


  • Vibrations of the particles are parallel to the direction the energy of the wave travels
• Longitudinal waves example

  • Sound waves
  • Ultrasound waves
• Conductor


  Allows electricity to flow through it easily
• Conductors


  • Copper
  • Iron
  • Steel
  • Metal
• Conductors


  • Allow electricity to flow
  • Lit up
• Insulator


  Do not allow electricity to flow through easily
• Insulators


  • Wood
  • Plastic
  • Rubber
  • Non-metals
• Insulators


  • Do not allow electricity to flow
  • Not lit up
• Cell polarity


  A cell has a positive end and a negative end
• Charge


  Positive (+) and Negative (-)
• Series circuit


  Components (such as a bulb) are connected in a sequence one after another or side by side
• In a Series circuit, if one bulb is broken/goes out


  All go out or stop working
• The more bulbs added in a Series circuit


  The dimmer they get
• Parallel circuit


  There is more than one branch through which electricity can flow
• In a parallel circuit, if one bulb breaks/goes out


  The other stays lit/keeps working
• The more bulbs added in a parallel circuit


  The brightness stays the same
• Penetrates


  Able to pass through
• Atmosphere


  The layer of gases surrounding the Earth
• THE ELECTROMAGNETIC SPECTRUM


  • Radio
  • Microwave
  • Infrared
  • Visible
  • Ultraviolet
  • X-ray
  • Gamma Ray
• Wavelength


  The distance between consecutive peaks or troughs in a wave
• Frequency


  The number of waves that pass a given point per unit of time
• Type of radiation


  • Gamma rays
  • X-rays
  • Ultra-violet
  • Visible Light
  • Infrared
  • Microwaves
  • Radio
• Gamma rays


  • Used for treating cancer, Sterilisation
• x-rays

  • Used for medical checking for broken bones
• Ultra-violet


  • Causes cell mutation/cancer, Used in sunbeds
• Visible Light


  • Used for seeing things, fibre optics
• Infrared


  • Used for remote controls, heat transfer
• Microwaves


  • Used for satellites, phones
• Radio


  • Used for TV/radio communication
• Dangers of radiation include cell mutation/cancer, sunburn
• Longer wavelength radiation has lower frequency
• Investigating energy transfer from food

  1. Set up equipment as shown in diagram

  2. Pour 20cm³ of water into the boiling tube

  3. Record the start temperature of the water

  4. Weigh 0.5g of each crisp

  5. Set the crisp alight and place under the boiling tube

  6. Record the end temperature of the water

  7. Repeat
• Variables


  • Independent - Type of crisp
  • Dependent - Temp change
  • Controlled - Volume of water 20cm3, Mass of sample
• Food tests


  • Starch (Iodine - yellow-brown to blue-black)
  • Sugar/Glucose (Benedict's - blue to brick red precipitate)
  • Protein (Biuret - blue to purple)
  • Fats (Ethanol - clear to white emulsion)
• Carbohydrates provide energy, fats provide energy storage and building/repairing cells, proteins provide growth and repair
• Vitamins and minerals keep you healthy, fibre keeps you regular, water makes up 75% of the body
• Longitudinal waves


  Vibrations parallel to the direction of wave travel