# Instructional design/Generate PBL Problems/1.2 Problems should challenge students

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## Problems should challenge students
### Video

This is a video of an art history teacher who fails to motivate her students. Please watch this video from 6:45, pay more attention on the section of 9:24 – 10:24 and think about the reason why this teacher fails to motivate her students.(To watch the video: press Shift and click the PLAY button):

### Reflection

In this video, the teacher fails to draw her students’ attentions because she doesnot think about her students’ prior knowledge; she starts the class by presenting the materials that she assumed her students don’t know. The result is apparent that her students donot buy it, and they even suggests the teacher that they could have an independence study by their own.
Even though it is not a PBL, the principle behind this video is the same as using PBL teaching methods. As instructional designers, we should generate a problem that would challenge students within their knowledge scope. The image below shows a metaphor for this principle. (Picture 1 to picture 5)
In picture 1, all the apples can be seen as problems. The difficulty levels of the problems vary, just like the heights of the apples. Some are lower, and some are higher.
In picture 2, the student’s height is her prior knowledge towards a certain topic.
In picture 3, the student does not take too much effort to reach the apple. This is the kind of problems that cannot challenge students. Students can easily come up with solutions towards such kind of problems, so they cannot be motivated.
In picture 4, the student uses a ladder to reach the apple. This is the type of problems that challenge students within their knowledge scope.
In picture 5, the apple is too high for the student to reach. This type of problems contain too many challenge factors that students won’t be able to solve.
Therefore, teachers should create problems that students have had certain prior knowledge to start working on. If the problem relies too much on prior knowledge, that will make students feel not being challenged enough; if it relies too little on their prior knowledge, it will make students feel frustrated.
Tips for instructional designers and instructor to generate challenging problems.
   * Gain information
-Truth Statements: Ask students to write a 5 sentence of “truth statement" about their past learning experience, and then ask students to exchange their experience in a group of 2, finally introducing their partners’ experience to the whole class. Remember to collect those statements so that you could have a copy of their prior knowledge.
-Opening Letter: At the start of a class, write a letter to students explaining what you want them to know, understand and be able to do in the upcoming unit and then ask them for a return letter about their concerns. This is a reverse way to know what students are not good at.
   * Provide additional information
-Just like in picture 4. remember to provide students with necessary new knowledge (the ladder) so that they could solve

### Quiz

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