Lab Reports and Evaluating Results

• Atoms, the basic building blocks of matter, were first discovered by the Greek Philosopher Democritus
• John Dalton used Democritus's ideas and used them to form the First Modern Atomic Model
• The first step to communicating your findings is to write a LAB REPORT
• Writing a Lab Report

  1. Title
  2. Introduction or purpose
  3. Hypothesis or Prediction
  4. Materials and Equipment
  5. Procedure
  6. Data or Results
  7. Conclusion or Evaluation
• Title - tells the reader about the experiment or investigation
• Introduction/Purpose - gives a brief description of the question that is being asked or why the investigation is being done. "What question am I trying to answer?" "What is the purpose of this study?". It can also include any research that may already exist about the topic
• Hypothesis/Predictions - States specifically what will happen in the investigation and why
• Materials and Equipment - list of all the materials and equipment that are necessary to carry out the investigation. You can even add a diagram or sketch of the materials needed for the setup
• Procedure - describes the entire step-by-step process that is followed during the investigation. Imagine yourself instructing someone who is completely unfamiliar with the experiment. The process should be as clear as possible
• Data/Results - gives a concise account of all the measurements and observations that you made during the investigation. This should be presented in an organized manner. It is helpful to use graphs, tables, charts, drawings, or even photographs. The most important thing in this part is accuracy and precision
• Conclusion/Evaluation - presents a summary of what you learned from the investigation. This can include a claim, evidence, and reasoning, in which you answer the initial question with a claim and show how your evidence supports the claim.
• Every investigation has 2 types of errors

  1. Systematic
  2. Random
• Systematic error - an error that affects the accuracy of a measurement
• Calibration - is when the readings of an instrument are compared to a known measurement to check its accuracy
• Parallax error - an error that occurs when you view the object from different points
• Random error - is caused by error in the experimental apparatus or by the person who is reading the measurement. It affects the precision of the measurement
• The precision of a measurement is determined by the number of digits reported
• Significant Figures - the numbers reported in a measurement
• Significant Digit - the number that provides the most exact measurement possible
• Estimation - a rough guess of the measurement using observation and reasoning
• Rounding - picking the closest number to be specified place value based on the accuracy of the equipment
• Percent error - the difference between measured value and a known value expressed as a percentage. It tells you about your measurement's accuracy
• Accepted value - known to be true and can be found in a standard reference
• Experimental value - the value that you actually measured
• Formula for Percent Error

  
• Accuracy - is how close your measurement is to a standard or known value
• Precision - is how consistent your measurements are to one another