Applied Science - Science and Math (2A)
Post Lab 

   
OBJECTIVES:
  • Estimating and gathering data.
  • Interpreting results from a data set.
VOCABULARY:
  • conclusion
  • guess
  • hypothesis
  • prediction
  • procedure
  • results
MATERIALS:
  • worksheet 
  • graph paper 

Students graph how much television they watch.

BACKGROUND:

If a subject interests students, they can usually think of many questions they would like answered. The first step in scientific work is to narrow the range of investigation so the question is answered by an experiment showing results in a reasonable period of time. "Why can't Johnny read?" and "Why don't I seem to have time to do everything I want to do?" are not good experimental questions. "How much television do second graders watch LAB the week?" is much better because it is a measurable quantity. The scientific method can be broken down into 3 steps.

     (1) Guess what is going to happen;
     (2) test your guess; and
     (3) record your results.

Do your results match your guess? If not, why not? Real scientists often learn more when experiments do not turn out as expected. They make a new guess and test it. It is important to remind students that there is no one perfect answer. A hypothesis is only a best guess. This guessing, testing and retesting is the most important thing for children to learn when proposing a science project.

PROCEDURE:
  1. Explain to students that over the next week they will become scientists testing the question, "How much television do second graders watch LAB the week?Ē Before scientists can answer a question they must first guess what they think will be the outcome.  This guess is called a hypothesis.   Ask students to decide how many hours of television they usually watch from Monday through Thursday.  You will get all sorts of numbers.  Pick one in the middle and see if the class agrees by taking a vote.  State their hypothesis formally: "The children in our class watch about X hours of television from Monday through Thursday."
      
  2. Inform the students that a scientist must now test their hypothesis (guess).  For this experiment a survey is sent home on Monday with each child.  Each student writes down how many hours of television he or she watches on Monday, Tuesday, Wednesday, and Thursday.  The surveys should be returned on Friday.  Ask the children to use whole hours or half hours.  If they only watch a fraction of a program ask them to round the time to the nearest half or whole hour.  They can ask their parents to help them with this.   If you send home a weekly letter to parents you may want to include this lab into the letter.  In this way the parents can remind the children to write in their times accurately.
      
  3. Reinforce the following points before they start the survey. The time must be accurately recorded and there must be a number for each day.  The children should follow their normal viewing habits as much as possible.  The idea is to get a real picture of how they spend their time, not to see if they can fudge the data to come closer to the time they guessed.  Real scientist do not "fudge" data.
      
  4. On Friday, each survey sheet should be checked to ensure that there are entries for all four days.  The total will change if a child forgets to write the hours down one day.  If there are blanks but the child thinks he/she can remember what programs were watched, fill in the data where missing.
      
  5. Model for the children how to add up the total number of hours watched LAB the four days.
      
  6. Allow them time to add their own numbers.  Ask them to have the student next to them check their work.
      
  7. Ask the children to decide into which of the following categories their hours fit.   List the categories on the board: 0 to 3 hour, 3 ½ to 6 hours, 6 ½ to 9 hours, 9 ½ to 12 hours.  
      
  8. Total the number of children in each category and make a bar graph.
      
  9. Report the range of results (the lowest number of hours watched and the highest number of hours watched).  Look at the graph and determine the most common number of hours watched.
      
  10. Look at the children's estimate again.  Discuss how their estimate compares with the results?

 

  1. You may want to summarize the results and include them in a parent letter.  Most parents donít realize how much television their children watch.  You may want to include alternate activities like reading a book or taking a nature walk to help parents spend more time with their children.

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