General Science Pointers

• Science


  Systematic study concerned with facts, principles, and methods that could be observed in our natural or physical and social environment
• Technology


  Application of scientific knowledge to improve life or satisfy needs
• Types of technology


  • Machines
  • Products
  • Processes
• Machines


  • airplanes, Internet, CT-scan, and computers
• Products


  • toothpaste, chemical fertilizers, and pesticides
• Processes


  • food preservation, prawn culture, and induced fruiting
• Technology has played a part in solving many problems in medicine, industry, and agriculture
• The world has benefited from science and technology, but there are also risks involved in technological advances
• Risks of technology


  • Hazards or negative effects that lead to loss or injury
• Risks of technology


  • Water pollution from fertilizers
  • Harmful health effects of food additives
  • Radiation destroying healthy cells
• Scientific method


  Logical method used by scientists to acquire knowledge that is used to explain different phenomena in nature
• Steps of the scientific method

  • Identify and clearly state the problem
  • Gather information pertinent to the problem
  • Formulate hypothesis
  • Test the hypothesis
  • Presentation of Data
  • Draw a generalization or conclusion
• Controlled Experiment


  Manipulating one of the conditions or factors that may affect the result of the experiment
• Trials


  The number of times an experiment is repeated
• Controls


  The factors that are kept constant throughout the experiment
• Variables


  • Independent or Experimental (factors that are changed)
  • Dependent (factors that change as a result of changes in the independent variable)
• Presentation of Data


  • Tables
  • Graphs (Line, Bar)
• Conclusion


  A statement about the result of the experiment
• Law


  A statement which describes what happens but does not explain the cause of the occurrence
• Theory


  Hypothesis that can be explained from observations
• Scientific knowledge may also be obtained through the use of models and ideas, or through serendipity or accidental discovery
• Scientific attitudes


  • Curiosity
  • Logic and System
  • Open-mindedness
  • Intellectual honesty
  • Hard work and perseverance
  • Objectivity
  • Creativity and critical thinking
• Measurement


  The process of comparing a quantity with a chosen standard
• SI units


  • Length (meters)
  • Mass (kilograms)
  • Time (seconds)
  • Electric current (amperes)
  • Temperature (Kelvin)
  • Amount of substance (moles)
  • Luminous intensity (candelas)
• Accuracy


  The degree of closeness of measurements of a quantity to its actual (true) value
• Precision


  The degree to which repeated measurements under unchanged conditions show the same results
• Matter


  Anything that occupies space and possesses the attributes of gravity and inertia
• States of matter


  • Solid
  • Liquid
  • Gas
  • Plasma
• Solid


  Characterized by resistance to any change in shape, caused by a strong attraction between the molecules
• Liquid


  Does not resist forces that act to change its shape, because the molecules are free to move with respect to each other
• Gas


  State of matter in which molecules are widely dispersed and freely move, offering no resistance to change of shape and little resistance to change in volume
• Plasma


  The fourth state of matter consisting of an overall charge-neutral mix of electrons, ions, and neutral atoms
• Most substances are solid at low temperatures, liquid at medium temperatures, and gaseous at high temperatures, but the states are not always distinct
• Melting Point/Freezing Point


  The temperature at which any given substance changes from solid to liquid and vice versa
• Boiling Point


  The temperature at which a liquid changes from liquid to gas and vice versa, depending on atmospheric pressure
• Physical change


  A change in matter that involves no chemical reaction, where the composition of its molecules remains unchanged and the substance does not lose its chemical identity
• Types of physical change

  • Melting
  • Evaporating
  • Freezing
• When a substance undergoes a physical change, the composition of its molecules remains unchanged, and the substance does not lose its chemical identity
• Boiling point


  The temperature at which a liquid changes from liquid to gas and vice versa. It is also defined as the temperature at which the vapor pressure of a liquid equals the external pressure surrounding the liquid.
• The boiling point of a liquid depends on atmospheric pressure. The boiling point becomes lower as the external pressure is reduced.