Materials:- 1 tea light candle
- 1 apple
- 1 cutting board and paring knife (a peeler also works well)
- lighter
- 1/4 cup lemon juice
- 1 bowl
- 1 raw almond
Procedure:Before the demonstration:1. Peel the apple and carve into the shape of a tea light candle using the peeler or knife
2. Pour lemon juice into a bowl. Soak the apple in the lemon juice in to keep it from browning
3. Carve the almond in the shape of a wick and place it on the candle
During the demonstration: 1. Light the real tea light candle and hold it out so the audience can observe it. You may want to circulate the class so all students can see the candle
2. Allow students to observe the candle while you light the apple with the almond wick. Hold the apple, almond candle out to the audience so they can observe it.
3. Quickly blow out the apple, almond candle and then bite it.
4. Ask students the following questions to demonstrate the difference between inference and observation:
(a) What can you tell us about candles?
(b) Based on your prior knowledge, are candles edible?
(c) Is it possible that our prior knowledge about candles, that they are not edible, is incorrect?
(d) Are candles edible? How do you know?
(e) Do you think the second candle we presented is a real candle? Why or why not?
(f) What do you call it when you make an assumption based on prior knowledge, without actually observing something? Inference
(g) Did you infer the edible candle was a real candle? If so, why?Explanation:This hook demonstrates the concept of inference. Inference can be defined as
a conclusion or opinion that is formed based on known facts or evidence. When conducting scientific investigations, scientists make observations and construct inferences based on their observations.
In science, students must be able to understand the difference between inference and observation. This hook would be great to use at the beginning of the year when students are first starting to conduct scientific investigations. This hook demonstrates the difference between inference and observation and could teach students how to distinguish between the two. When the first candle is presented to the students to observe, they can easily determine that it is a candle. The candle is made out of wax and the wick is burning. On the other hand, when the second ‘candle’ is presented to the students, they do not have as much of an opportunity to observe the candle and are not able to use all of their senses and resources. Instead, the students have to rely on their sight to determine if it is a candle. Further, the students infer the second ‘candle’ is a candle based on prior knowledge and assumption. One makes the assumption that since the first item displayed is a candle, the second item must be a candle. When you then take a closer look to validate your inference, you realize that the edible ‘candle’ does not look like an actual candle.
It is important in biological science to make evidence based observations rather making inferences. For example, granular dry yeast looks similar to sand. When presented with both, using sight and prior knowledge one might assume they are the same when in fact one is living and the other is non-living. Following observation with sight, one could make further observations using sense such as smell for validation. Further, students could make more observations by forming mini-experiments such as placing each sample in water and determining what happens.
Overall, in scientific investigations it is important to be observant, use your resources and not make inferences. As demonstrated in this hook, making inferences can lead to inaccurate conclusions. When inferences are made, further investigation should follow to form evidence based observations.
Course: SNC2D - Science, Grade 10 Academic
Unit: A.1 Scientific Investigation Skills
Expectations addressed: A1.1 Formulate scientific questions about observed relationships, ideas, problems, and/or issues, make predictions, and/or formulate hypotheses to focus inquiries or research
Note: This hook would be appropriate for grades 7-12.
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