Posted by David R. Wetzel, Ph.D.
Discrepant Events
Discrepant events are one form of minds-on thinking designed to help students focus on their prior conceptions of about the world in which they live.
This step is necessary if students are to alter their conceptions and internalize accepted scientific views.
This discrepant event provides concrete evidence of the Meniscus effect of liquids in containers, along with surface tension.
Materials:
one clear glass, one small cork, and tap water.
Procedures:
- Students fill glass two thirds full of water
- They now place the cork in the glass of water and try to keep it floating in the center
- Ask students if they can keep the cork in the middle and explain what they are observing
- Students observe the cork always moves to the edge of the glass (answer: cork moves to highest water level because the cork is less dense than water – meniscus effect)
- Ask students what they think will happen to the cork if the class is filled with water
- After discussion, students now add water to the glass so that it creates a bubble of water on top the glass, without overflowing (cork is still in glass)
- Students now observe the cork moves to the center of the glass (answer: the cork moves to the highest point because it is less dense than water and the cork is held in place due to surface tension)
The use of discrepant events is the best way to motivate the unmotivated student and engage all students in critical thinking.
The use of the materials above are typically within the realm of most students’ personal experiences and knowledge, which makes the mental conflict and resulting better understanding of related science concepts more meaningful for them.
Related Resources:
Discrepant Events and Critical Thinking
More Discrepant Events in Science
Posted by David R. Wetzel, Ph.D.
When I was teaching one of my students’ favorite events in science was when they are challenged with discrepant events. So what is a discrepant event?
It is something that surprises, startles, puzzles, or astonishes students as they observe the event.
Often, a discrepant event is one that does not appear to follow basic “rules of nature” and the outcome is unexpected or contrary to what they predicted.
The event throws the students “off balance” intellectually, which typically motivates them to further investigate the science concept – minds-on.
Discrepant events promote problem-solving and critical thinking skills on part of the students. They are typically guided into finding a solution by the teacher, as they discover the reason for the discrepant event.
How I Used Discrepant Events
I would guide students to answers using open-ended questions, which caused my students to draw upon their prior knowledge and experiences (PKE).
I would begin a new unit or chapter with a discrepant event to stimulate their thinking processes, along with finding out what they already know. Then I would use a culmination event to reinforce science concept(s) studied and as post informal assessment. .
I would present some discrepant events as whole class demonstrations. However, my ultimate goals was to make them group investigations as much as possible.
How are Discrepant Events Used
Discrepant events can be used:
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To engage students in inquiry
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As a demonstration followed by discussion to introduce a new topic
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To engage students in science processes skills
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As a small group lab activity
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As a mind-on warm-up to stimulate critical thinking
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As a take home lab activity
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As a challenge for students to create investigative lab activities to find out more about the event
Additional Resources
Additional examples of discrepant event activities and procedures can be found by visiting:
Science Discrepant Events and Critical Thinking
Three More Discrepant Events in Science
