Faraday's Candle Observations

Russ Riley
South Junior High School
St. Cloud MN
In 1860, Michael Faraday delivered the last of his very popular 'Christmas lectures' called 'The Natural History of a Candle'. His account has served as the basis for lessons in taking observations in science ever since. Here is a variation of this lesson, with some instructive details about Faraday himself.

Lessons

Extension Activities

The curriculum material here was developed as part of a project sponsored by SciMath-MN and The Bakken Library and Museum. Click to see directory of other curriculum modules using history and philosophy of science in this series.

INTRODUCTION:

The idea for the science activities that follow came from a book entitled, THE CHEMICAL HISTORY OF A CANDLE, by Michael Faraday. The book, first published around 1860, was actually taken from notes written by William Crookes while he attended Faraday's lectures. A reprint or reproduction of the book was issued in 1960 by Viking Press as part of an Explorer Books series. It is that version that would likely be available for teachers to use as a reference.

Michael Faraday, born in 1791, by all accounts displayed an early curiosity about the natural world and also had a great love of tools and fine workmanship. He is, of course, well known in the scientific world for his extensive work in the area of electricity and magnetism with a special interest in the area of electrochemistry. Much of his work was done during the nearly forty years he served as the Superintendent of the House and Laboratory at the Royal Institution in London. He also had a special interest in the process of thinking and learning. This interest, combined with a concern and love for children, led to the development of a series of lectures given to young people that became known as the "Christmas Lectures". Beginning just after Christmas in 1826 Faraday delivered the lectures himself a total of nineteen times covering the fields of chemistry, electricity and magnetism, gravitation, as well as other topics in physics. One of the last lectures to be given, delivered in December of 1860, approximately seven years before Faraday's death, was entitled, "The Chemical History of the Candle". As previously stated, this lecture was the basis for the book and the inspiration for the science activities that follow.

It should be noted that the activities to follow are designed to be primarily an introduction to the scientific process. They are meant to stimulate curiosity, raise questions, and to begin the practice of making open minded observations. That young people learn to do this was obviously very important to Michael Faraday and thus is very useful as background for the observation activities. The use of a burning candle to practice the process of science is not new. However, these activities have been written specifically as a supplement to the Introductory Physical Science (IPS) curriculum. It is the intention and hope that other teachers will be inspired to modify and adapt as needed to fit individual situations.

LESSON 1

OBJECTIVE: The student will practice making observations by:

PROCEDURE:

  1. Set up candle as instructed.
  2. Describe the candle while it is not burning.
  3. Light the candle carefully.
  4. Let the candle to burn for about 10 - 15 minutes making all of the observations you possibly can. Write your observations down.
  5. Blow the candle out. Continue to observe the candle. Write your observations down.

FOR FURTHER INVESTIGATION:

  1. Remove a wick from a candle. Place the end of the wick in a dish of water. Light the wick. What do you observe? Place the wick in a dish of lamp oil or kerosene. What do you observe? What conclusions can you make? Is it necessary to have a material that burns in order to make a lamp or candle? Is it necessary to have solid wax to make a candle?
  2. Cut away some wax from the base of candle to expose the wick. Place the exposed wick in a dish of water. Light the candle. Light the candle. Predict if it will continue to burn or not. Record your observations and conclusions.

OF POSSIBLE INTEREST:

Experiments with a candle were demonstrated to young science students over 130 years ago by Michael Faraday, an English chemist. Try to find out something about Michael Faraday and his discoveries about science. There is even a book entitled, The Chemical History of a Candle.

LESSON 2

OBJECTIVE: The student will develop questions from the observations.

Before asking the students to raise questions about their candles give some brief background about Michael Faraday (See "Chemical History of a Candle" by Michael Faraday; Explorer Books by Viking Press; New York, 1963.) Read an excerpt from the Christmas Lecture Number 1, Page 9 to the students. "Now the greatest mistakes and faults with regard to candles, as in many other things, often bring with them instruction which we should not receive if they had not occurred. We come here to be philosophers (scientists) ; and I hope you will always remember that whenever a results happens, especially if it be new, you should say, 'What is the cause? Why does it occur?' and you in the course of time will find out the answer." This is done to emphasize the importance of asking questions and to develop an introductory interest in Michael Faraday.

  1. After sharing observations students should develop a list of questions about the unburned candle. Examples:
    • Why is the wax white (or whatever the color is)?
    • What is wax?
    • What is the wick?
    • Why is the wax soft?.............
  2. After sharing observations students should develop a list of questions about the burning candle. Examples:
    • Why does the wick turn black?
    • Why does the wax melt?
    • Why does the smoke burn?
    • Do all candles burn the same?...

(NOTE: The questions can serve as a discussion point in that they could lead to further investigation at some point in the future. Such is the nature of science.)

LESSON 3

OBJECTIVE: The student will compare the flame produced by a Bunsen Burner to that of a candle and reach conclusions based on observation data relative to the following questions:
  1. Where does the hottest part of the flame seem to be?
  2. What does the flame color have to do with the temperature of the flame?
  3. Compare the flame produced by the candle with the flame produced by the Bunsen Burner.

Materials: 6 inch candle, semi micro burner, heavy cardboard cards approximately 5 cm square)
Note: For best results do this in a semi darkened room.

PROCEDURE:

  1. Light the Burner as directed. Practice changing the size of the flame using the gas control.
  2. Practice opening and closing the air control.
  3. Adjust the flame to a height of about 2.5-3 cm. Keep the air control closed. Sketch the flame including not only the shape, but the color and where the color occurs.
  4. Now open the air control. Again sketch the flame. Be sure to notice any differences compared to when the air control was closed.
  5. Now light the candle. Sketch the flame as you did with the burner.
  6. Place the burner and candle next to one another. Light the candle. Light the burner with the air control closed. Compare the two flames.....How are they the same? How are they different?
  7. Now open the air control on the burner. Compare the two flames...How are they the same? How are they different?
  8. Put the burner aside. Have a container of water at your desk to use as a fire extinguisher before you proceed. Light the candle. Carefully place a card in the flame as directed. Hold in place for several seconds. REMOVE QUICKLY IF CARD STARTS TO BURN. Remove the card. Examine the scorch pattern on the card. Make a sketch of it.

OF POSSIBLE INTEREST:

Find out about Robert Bunsen. Did he live before, after, or during the time of Michael Faraday? What do you believe led to the development of the Bunsen Burner? Be prepared to report to the class on your findings.

Extension Activities

  1. Read Faraday's Christmas Lecture 1.

    • Observe flames from several different types of candles, ie birthday candles, decorative candles, beeswax candles, etc., . . . compare and contrast to the original set of observations.
    • Observe flames from several difference sources, ie candles, Bunsen, burner, alcohol lamp, etc....compare and contrast.
    • Investigate capillary action using paper towels, toilet paper, other porous materials. Try to repeat Faraday's salt block demonstration. Use what is learned to explain how the wick of a candle works.

  2. Read Faraday's Christmas Lecture 2

    • Choose one of Faraday's demonstrations or experiments and try to repeat it. Compare your results with Faraday's. Try to explain any differences.
    • Choose one of Faraday's demonstrations.....find out about some of his contemporaries (Sir Humphrey Davy, William Crookes...others. Write a short play with characters to carry out one of the lectures.

  3. Interdisciplinary Links

    • Investigate the use of candles and other types of lights in several different cultures. What differences and similarities did you discover? What could be reasons for the differences and similarities?
    • Investigate what schools were like in England during time that Michael Faraday lived. What was taught? What was taught about science? Why were the Christmas lectures important to science education? Who were the young people or students who attended the Christmas Lectures? Was science education given to other young people at the time. What were schools like in America during that time? Was science taught in the American schools?
    • Go through all of Faraday's lectures and make a list of words that are no longer used or have difference meaning in our modern language. How do you think the changes came about. What examples can you come up with that may indicate that our current language is changing?