science end of unit

• biotic factor - all living things
• abiotic factors - non-living things
• examples of biotic factors - grass, animals and plants
• examples of abiotic factors - sun, air, soil, water, rocks
• parasitic - relationship between 2 organisms where one lives on or in the other and feeds off of it.
• predation - relationship between 2 organisms where one organism kills and eats the other
• Photosynthesis - carbon dioxide + water -> glucose + oxygen
• Producers - organisms that get their energy through photosynthesis
• consumer - feed on other organisms to obtain energy and nutrients, and to grow
• function of the endocrine system - to produce hormones in response to stimuli to maintain a stable internal environment and homeostasis
• fossil fuels - an unrenewable source of energy that is formed within the earth's crust from biological remains
• 3 types of fossil fuels - oil, natural gas, coal
• nervous system function - collects and processes information about the internal and external environment
• CNS - sends messages directly to and from the brain through the spinal cord
• PNS - peripheral nervous system - all the nerves outside the brain and spinal cord and sensory and motor nerves
• reflexes - not conciously controlled, faster and produced by the spinal cord
• reaction - conciously controlled, slower and produced by the brain
• similarity between reaction and reflex - both involve a stimulus being detected by a receptor
• Atomic number: smallest number 
• Atomic mass: larger number  
• Number of protons = atomic number 
• Neutrons = atomic mass – atomic number  
• Electrons = atomic number = number of protons 
• combustion - the burning of fossil fuels
• combustion - always produces carbon dioxide and water
• chemical reaction - the rearrangement of atoms to create a new substance
• nuclear energy - energy released by the splitting of atoms in a nuclear reactor.
• nuclear decay - the breakdown of unstable atomic nucleus resulting in the release of energy/matter.
• acid - a solution that contains hydrogen ions H+
• Acid characteristics 

  • Taste sour 
  • Conduct electricity – anything that forms ions can conduct electricity 
  • Corrosive – break things down, holes e.g. metal 
  • React with metals to produce hydrogen gas 
  • Turns litmus paper red 
  • PH lower than 7 
• Base  

  • A solution that contains hydroxide ions (OH-) 
  • Also called alkalis 
  • Strong base – lots of hydroxide ions  
  • Weaker base doesn't have much 

   
• Base characteristics 

  • Looks slippery or soapy 
  • Bitter taste 
  • Conduct electricity 
  • Don't react with metals 
  • Turn litmus paper blue 
  • PH above 7 
• pH scale - a scale used to measure the acidity of a solution
• universal indicator - a dye that changes colour in the presence of pH