Now You See It, Now You Don't

Material:

A Candle

An apple

a. soak the apple in lemon juice to keep it from browning

b. carve the apple in the shape of a candle

3. An almond

a. carve the almond in the shape of a wick

Future Quicktime Movie and photos of the demo to go here!

Procedure:

1. Light the candle and give it to the audience so that they can observe it.

2. While they are observing the candle, light the apple with the almond wick.

3. Show the apple, almond (candle) to the audience

4. Quickly eat the apple, almond candle (make sure you blow it out first)

Questions:

1. What do you know about candles?

2. Based on previous knowledge you have on candles, are the edible?

3. Is it possible that what we already know about candles (they are not edible) could be incorrect.

4. How do we know if candles are edible or not.

5. Do you think that the second candle (the edible candle) is really a candle? Why or why not?

6. In science, what is it called when we assume without actually observing it?

7. Why did we infer that the second candle (the edible candle) was really a candle?

8. Name 3 different example of Inference.

Rationale:

This demonstration is a great tool to introduce the idea of inference. It is important for students to understand and distinguish the differences between inference and observation. The first candle was given to the students to observe. In this instance they could easily tell that the candle was made out of wax and it was indeed a candle. However, the second candle the students were not able to observe the candle by using all their senses. Instead they had to rely on seeing which as we know is not always reliable. This demonstration teaches students that it is important in science to be observant and try not to make inferences.

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