Science reviewer

• In 1928, researcher Alexander Fleming unintentionally left a dish (in which bacteria were growing) exposed in his laboratory when he went on vacation
• When he returned, he noticed that there were no bacteria growing in certain areas of the culture medium
• Upon investigation, he found out that those areas were occupied by the mold Penicillium notatum
• He investigated further and discovered that the mold produced a substance (which he called penicillin) that prevented the growth of certain bacteria
• To Explain a Natural Phenomenon


  One purpose of scientific research
• To Find Ways of Improving People's Lives


  One purpose of scientific research
• People's lives may be improved through the development of new products, gadgets, and processes or ways of doing things
• In 1853, Elisha Otis developed a freight elevator equipped with a safety device to prevent falling in case a cable supporting it breaks
• While primitive elevators were already used as early as the 3rd century BC, Otis invented the brake used in modern elevators
• To Discover and Formulate New Concepts and Theories in Search of Truth


  One purpose of scientific research
• One of Albert Einstein's greatest contributions to science is the General Theory of Relativity in 1916
• His work gave the theoretical basis of later scientific and technological advances like electronics, space travel, and the atomic bomb
• It also made us understand different concepts like subatomic forces and the universe (explaining the Big Bang theory and black holes)
• How scientists conduct research

  1. Identifying the problem

  2. Gathering preliminary data

  3. Formulating a hypothesis

  4. Testing the hypothesis

  5. Analyzing the data

  6. Drawing a conclusion

  7. Verifying the conclusion
• Before Ms. Gatdula went on vacation for two weeks, she instructed her helper to care for her potted plants during her absence
• Throughout the warm weeks, the helper decided to give each of the plants one dipper of water thrice a day, thinking this would be good for them
• Within two weeks, the plants wilted
• Anthony, a nephew of Ms. Gatdula, learned about the incident and wanted to be sure of the cause of the wilting of the plants
• What Anthony did


  1. Bought six small potted plants of the same kind as those that wilted

  2. Kept them in his garden for a week

  3. Assigned the plants into two groups: Group 1 and Group 2

  4. Made sure all plants have the same kind of soil and placed in the same part of the garden

  5. Watered the plants in Group 1 with a dipperful of water three times a day

  6. Watered the plants in Group 2 using the normal amount of water

  7. Observed that the plants in Group 1 considerably wilted while the plants in Group 2 flourished
• Alfred Bernhard Nobel invented and manufactured explosives so that people will use them solely for peaceful purposes like blasting, hole digging and removing stumps for construction work
• When he saw that his explosives were being used for war, it saddened him very much
• The Nobel Foundation was established after his death to take his wealth for the purpose of awarding the Nobel Prize to individuals who have made outstanding contributions to mankind in fields indicated in his will: physics, chemistry, physiology and medicine, literature and peace
• Measurement


  The process of comparing a quantity of mass or length with a standard unit such as meter, gram or second
• Humans are by nature curious beings. From our childhood we ask questions about things we see around us
• We observe, we describe what we observe, and we write down or report our observations
• Use of Measuring Instruments

  Observation becomes more accurate when we measure quantities with the use of instruments
• Examples of measuring instruments

  • Meterstick for measuring length
  • Platform balance for measuring mass
  • Clock or stopwatch for measuring time
• Reporting Results of Measurements

  Numbers, as results of measurements, must be reported with the appropriate standard units
• The two systems of standard units

  • Metric system
  • British system
• Examples of standard units in the metric system

  • Meter (m) for length
  • Kilogram (kg) for mass
  • Second (s) for time
• Examples of standard units in the metric system (Set B)

  • Centimeter (cm) for length
  • Gram (g) for mass
  • Second (s) for time
• Fundamental quantities


  Length, mass, and time are three examples of fundamental quantities, so called because other quantities, called derived quantities, are obtained from them
• Area is obtained by multiplying two measurements of length (e.g. length x width)
• Volume is obtained by multiplying three measurements of length (e.g. length x width x height)
• Examples of standard units for derived quantities (Set A)

  • m² for area
  • m³ for volume
  • kg/m³ for density
• Examples of standard units for derived quantities (Set B)

  • m² for area
  • m³ for volume
  • g/cm³ for density
• In reporting results of measurements, the values must always be accompanied by the appropriate units
• Scientific Notation


  Scientists have a way of expressing very big or very small numbers
• Sunspots have an average diameter of 10,000 km = 1 x 10⁴ km
• The diameter of some large sunspots is 20,000 km = 2 x 10⁴ km