Using “What if..” questions to teach science

Table 2: Breakdown and frequency of the types of “What if…” questions posed by students.

Unfortunately, the lively discussion during the presentation of the students’ “What if..” questions was not documented on paper on the spot or recorded in any media form. However, some typical examples of peer responses to the posed questions are summarized in Table 3. A few of the peer responses may not be technically sound and some may be incorrect. It is important to have these misconceptions addressed immediately, and on the spot, by the teacher. This was done each time the teacher identified a misconception during the discussion. Table 3 also shows some examples of students’ misconceptions identified from their posed questions and peer responses.

“What if..” questions and typical peer responses

1. “What if there was no boiling stones in the flask?”

Typical peer responses:

a. “There will be no boiling in the water.” (Misconception)

b. “Boiling will spill out of the flask.” (Possible, especially if “bumping” occurs and may cause the boiling liquid to spill out through the thermometer adaptor.)

What could happen and why it happened:

The boiling stones provide jagged surfaces for dissolved air to form small air

Bubbles. This will prevent the formation of a big air bubble at the bottom of the

flask which would attempt to “break free”, hence the “bumping” phenomenon.

2. “What if the positions of the water inlet and outlet of the condenser were switched?

Typical peer responses:

a. “There will not be any liquid collected.” (Misconception)

b. “There will be less liquid collected.” (Actual result)

What could happen and why it happened:

The direction of condensing medium (cold water) in the jacket of the condenser should be opposing the direction of the hot vapour entering the condenser through the tube. This way, there will always be a maximal temperature gradient between the hot vapour and cold condensing medium, resulting in a large amount of vapour condensing into the distillate. By switching their positions, the temperature gradient will be greatly reduced and somewhere midway or so in the condenser, the temperature difference between the vapour and the medium may not be significant enough to continue a good condensation process, hence the amount of distillate obtained will be reduced.

3 “What if there were no thermometer in the set up?”

Typical peer responses:

a. “I cannot do the experiment, because I cannot read the temperature.” (Fair enough, but distillation can still continue without the thermometer in place.)

b. “The distillation will be slower.” (Misconception)

What could happen and why it happened:

The thermometer serves only as a monitoring instrument in this apparatus set up. It does not contribute to the distillation process. The distillation will still continue as usual, at the same rate, with or without the thermometer.

Table 3: Typical peer responses (verbal) to “What if…” questions posed by students

	Conditions	Broad Questions Asked	Frequency
A	Missing materials	1. “What if there was no boiling stones in the flask?”	6
B	Change in set up of apparatus (including missing pieces)	2. “What if the positions of the water inlet and outlet of the condenser were switched?	2
		3 “What if there were no thermometer in the set up?”	1
		4. “What if there were no condenser?”	5
C	Change in choice of apparatus or materials	5. “What if candle(s) was/were used in place of the Bunsen burner?	2
		6. “What if hot water was used in the condenser instead of cold water?”	1
		7. “What if the flask is made up of a different material (other than pyrex glass)?”	1
		8. “What if there are other particles in the seawater?”	1
D	Change in physical or environmental conditions	9. “What if the room conditions were changed (higher or lower than standard)?”	4
D	Change in physical or environmental conditions	10. “What if a smaller (Bunsen) flame was used?”	2
E	Unexpected experimental results	11. “What if the water distillate was tested to be impure?”	1
		Total number of “What if” questions generated =	26