Homework

In today's classrooms, critical thinking is evaluated by homework, in-class quizzes and exams. Obviously, in-class activities have the added benefit of being monitored to ensure that the submitted work reflects the true ability of the learner. But, it is technologically possible to create an online homework system that reports a reasonably accurate assessment of the learner's ability. The key is to randomly assign similar questions such that no two students have the same problem set and that any help obtained on a problem will require the "helper" to demonstrate their thinking process from start to finish. Even in algorithmically generated questions, this is not the case as "short-cuts" are possible to "get the answer." Homework problems in the Chem21Labs' approach are grouped into "problem groups" (5 - 25 similar but algorithmically different questions) that covers the major topics of each chapter. A student's homework assignment will contain 1 or 2 randomly selected problems from each of the "problem groups". This approach to generating a homework assignment guarantees that each student has a different problem set while covering the same material. There are a variety of problem types available and an overview of each type follows:

  1. Multiple Choice - 2 to 25 choices (text or image) are possible for each question. Incorrect choices are greyed-out so students can't re-select them.



  2. Multiple Select - there are 2 or more correct answers . . . . up to 20 "choices." (text or image). Incorrect choices are greyed-out so students can't re-select them. A sample question is shown to the right.





  3. Short Answer (or Fill-in-the-Blank) - if a student enters an incorrect answer, the program will display to the student all the characters at the beginning and ending of the answer that they entered correctly. This information gives the student immediate feed-back on where they made a mistake. This problem type is used extensively for naming compounds in both General and Organic Chemistry. In the example below, SO3, Sulfur trioxide, was incorrectly named Sulfur dioxide . . . . the student receives immediate feedback that the green parts of the answer are correct and the red part is incorrect . . . .  Sulfur         ioxide .



  4. ChemDraw - students draw the answer on the webpage using the ChemDrawJS drawing palette.


  5. Unordered Text Answers - this problem type uses ChemDraw to submit isomers and resonance structures where the answers can be entered in any order.
    Draw the three additional resonance structures for the cation to the right.







  6. Balancing Chemical Equations - an equation template has been developed that contains 4 pieces of information for each chemical species . . . two required: coefficient and chemical formula . . . . two optional: charge and physical state. Instructors can easily customize this template such that the first assignment may require the student to enter the coefficient; a second assignment may require the student to enter the chemical formula and coefficient, a third assigment may require the student to enter an ionic equation (students must supply the charges and physical states), and a fourth assigment may require the student to enter a net ionic equation.


  7. Balancing Nuclear Equations - a slightly different version of the Balanced Equation template has been developed for submitting Nuclear Equations. This template contains 4 pieces of information for each species: coefficient, atomic number, mass number and chemical symbol. Students receive immediate feedback on their answers and have multiple attempts to enter the correct answer.

  8. Multiple Short Answers - this problem type is used for multi-part questions like

    Provide the following information for 56Fe0.
         56 is the mass of this particular isotope.
         0 is the charge on this particular isotope.


  9. Numeric Answers - this problem type requires a numeric answer that the computer evaluates to see if it falls within the tolerance established by the instructor.

  10. Ordering - this problem type requires the user to click / drag the displayed content in a certain order. A working model is found at Ordering Procedure Steps. The image below shows the feedback received after the first submission for the question . . .

  11. Arrange the following kinds of electromagnetic radiation in order of increasing wavelength.


Another very successful (although unconventional) homework approach used by the Chem21Labs' founder (Eddie Brown - Lee University 1990 - 2017) is to give the class the same homework problems (45 - 50 per chapter for General and 60 - 75 per chapter for Organic) and "accept" that students will work together to get the answers. Part of this acceptance is to only award 5% of the course grade to homework. What makes this a critical thinking process is that students are incentivized to learn HOW to arrive at the answer because the in-class exam will only contain questions from this homework pool. If the exam is over three chapters, the Organic homework pool would be 180 - 225 questions and the exam would contain ~ 20 questions. In addition, once a student knows HOW to answer a question, they become the teacher when their help is needed by a classmate struggling with that question.

As an expert in General Chemistry, give your expert opinion in the following situation: a student in your class reads Chapters 1 - 3, makes and daily uses flash cards to move critical course material into long-term memory, and works through the sample problems in the text book, problems covered in lecture and homework problems until she can both correctly answer the problems AND explain the answers to another student. What grade would you expect them to receive on the in-class exam? Most of you likely said an A or B. The problem is that a self-motivated student like the one described is rare . . . and the majority of the "educational experts" advise me (a chemist) to spend time with each student and "motivate them". They have great slogans and suggestions:

  • Be the "sage on the stage" to motivationally "wow" them.
  • Be the "guide by the side" to motivate them to "take this journey" with me.
  • Students "don't care how much you know until they know how much you care".
  • "Great teachers inspire."
  • "Attend campus events / intramural games of your students and they will invest more in 'your class'."

After doing all of these, I decided "there had to be a better way" because the my time investment was not producing the desired results. The problem needed investigation and I decided to use a proven strategy . . . . the scientific method. I am periodically stunned to hear scientists say something like "a student told me they really enjoyed ______ so I'm going to incorporate ____ in more of my classes because it really works."

I prefer to stick to the scientific method:

  1. Question: what steps can the professor implement to improve the class' general knowledge and critical thinking skills in Organic Chemistry.
  2. Background Research: I interviewed top students to see how they studied and found out that if the Chapter 1 - 4 exam was coming up on Monday, the top students spent 2-3 hours on Chapter 1 on Wednesday, Chapter 2 on Thursday, Chapter 3 on Friday, Chapter 4 on Saturday and reviewed on Sunday. This meant that the class time in the weeks prior to the exam was filled with students that were not prepared to critically think.
  3. Hypothesis: if I could devise and implement a learning system where novices constructed a database of course information similar to the expert's (my) database, then class activities would be understandable, thought-provoking and valuable. In addition, this database would store items in long-term memory that can easily flow into working memory allowing students to successfully solve problems requiring critical thought.
  4. Experiment: used spaced-retrieval of course-critical facts to build memory constructs in long-term memory. Assign critical-thinking questions as homework and add importance to these questions by asking a subset (~ 10%) of these questions on the next exam.
  5. Test: The American Chemical Society (ACS) Organic Chemistry Exam was used as the Spring semester Final Exam. This test was given at Lee University (Cleveland, TN) from 1990 - 2017 by the same Organic professor. The average ACT scores of the 637 students who completed the Organic Chemistry sequence during the 27-year span was 27.
  6. Analyze Data and Draw Conclusions: the Organic ACS Exam Scores (1990 - 2017) increased by > 18 percentile, the number of A/A- increased from 19.4% to 44.0%, and attrition in 2nd semester Organic went from 15% to 0.8%. The unconventional exam-prep approach described above uses Timed / Repetitive Quizzes to obtain better results than reading the chapter and making / using flash cards. Once these mental constructs are formed, the student's innate mental processing architecture is engaged in problem-solving activities where this stored information is accessed, pulled into working memory, and connected to create a constantly evolving chemistry schema. When the student's intrinsic abilities fail, their schema can still be altered - by a classmate, textbook, internet, tutor, TA, or Instructor - an alteration that the learner hopes will persist at least until the next exam. With this approach, every student can be successful because their schema can be as effective as any other student's schema when used to answer in-class exam questions. How does this schema perform in novel situations? The ACS Exam Results suggest that the students' schema constructed in 2005 - 2017 is superior to those constructed between 1990 and 2005. Additionally, it seems reasonable that a superior schema would persist longer in the student's memory than an inferior schema.

    The TRQ / Exam Question Pool approach works for the following reasons:

    • Students can earn 100% of the TRQ points if they are willing to work . . . . in one of the TRQ "options" points are awarded after 75 correct answers.
    • Students can earn 100% of the exam points if they are willing to work until they can answer (and show their work) every question in the exam pool.
    • Students have no excuse for not getting the grade in the class that they want. Before this approach was implemented, I would hear
      • "Those questions came out of left field."
      • "If I studied 20 more hours, I would not have scored higher on the exam."
      • "It's too hard."
      • "I don't understand Chemistry."
      • "I'm going to lose my scholarship."
      • "This class is going to keep me out of medical school."
      In the years (2005 - 2017) where this approach was used I had zero students stop by my office and ask "how can I get a better grade in this class?" It was obvious to them that my answer would be "earn all your TRQ points and then work on your exam questions until you can correctly answer any of them when you come into the exam."
    • This approach has allowed me to immediately see the student as they are:
      • Students (1%) that don't do their TRQs and then fail the exam, simply do not want to work in your class and do not care if you know that about them. There is nothing you can do to motivate someone that doesn't want to do anything.
      • Students (55%) that feel this approach is too much work . . . they do most of the TRQs and about 50% - 75% of the questions in the exam pool. These students typically make C's and B's because about half of the questions on the exam are new to them.
      • Students (30%) that are "workers" - they are willing to work. They take advantage of recitations and office hours when they have questions. They appreciate the fact that the work is 100% prescribed and straightforward . . . nothing "out of left field". They do the work and perform very well on exams and in the course. It is this group of students that is"on the bubble" concerning graduate / professional school . . . . the structured TRQ / Exam Questions approach tips the scale.
      • Students (15%) that just "get it". You won't see them in office hours, but they are the top performers in the class.
    • The professor (like a coach) sets the schedule for learning new information and maintaining this information in the "learned state". In addition, homework problems that require the learner to engage parts of their schema that will be expanded in upcoming chapters can be re-assigned so that the new construction occurs more easily.

An added pleasure of this approach is that it makes homework help sites (i.e. Chegg, StudyPool, HomeworkDoer, Yahoo Answers, DoMyHomework123, etc.) unnecessary. Students can keep their money because their classmates and school resources (tutors, TAs, professors) will be there to assist them . . . . now, that's a "guide by the side."