Teaching Science Using Discrepant Events to Engage Students

Posted by David Wetzel

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:

• To engage students in inquiry
• As a demonstration followed by discussion to introduce a new topic
• To engage students in science processes skills
• As a small group lab activity
• As a mind-on warm-up to stimulate critical thinking
• As a take home lab activity
• 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

Elementary Student Math Misconceptions

Posted by David Wetzel

Second-grade students are often taught to line up columns of numbers to add them. This works when they are adding whole numbers. But in third grade, when they add decimals, lining up

numbers can produce the wrong sum if the numerals have different significant digits.

The key is to make sure students understand the mathematical concept of addition, not just the procedure for how to do it.

The following math misconception examples are a result of students memorizing procedures and not actually understanding math concepts.

Example 1

While giving a ‘standardized’ test to a group of students I had never worked with before, one student called me over and asked how to ‘round off’ 65.23.  I explained that this was a test and I couldn’t actually teach how to do things.  She looked up plaintively and said, “Please just tell me if it’s closer to the 65 or the 23.”

Example 2

If a company can make 500 cartons in .8 hours, how many cartons can it make in 2 hours?

Conrad insisted it was a unfair question since they did not tell how many cartons were made in 1 hour and it could not be solved without that information.  Carmen had used 8 hours instead of .8 hours and insisted her answer of 125 cans was correct because only the decimal point was in the wrong place.

Example 3

Today student Sara was angry at me after taking a test on fractions.  She said it was unfair for me to ask what 2/3 of 12 was when I had not used 2/3 in an example in class.  She said she had studied only halves, fourths, eighths and sixteenths so she could not do thirds.

She said she had memorized the rules and could do the problems from the book, but she could not do such difficult problems as shading in 2/3of 12 squares.

Shade in 2/3 of 12

Additional Resource

Visit 5 Misconceptions in Elementary Math for more examples and strategies to eliminating math misconceptions.