Does candle lose mass when melted down?

Introduction: (Initial Observation)

Candles are found in different shapes and are used in different occasions. From birthday parties to religious ceremonies, restaurants to churches, dinner tables to bathroom vanities candles are seen in every corner.

When candle burns, it melts and the melted wax solidifies again on the sides or at the foot of the candle.

I have always been wondering if the melted candle wax is reusable. Maybe that is why some candle manufacturers use glass cups as candle sidings, where melted wax can not leak out.

After a candle is burned to its foot, we can see a pile of wax at the bottom of it. Did you ever think how much wax comes off each candle? Is it the same amount as the initial candle? Is it more? Is it less?

In this project you may find the answer for yourself. You may also compare different candles for any possible change in their masses.

Information Gathering:

Find out how candles are made and how they work. Read books, magazines or ask professionals who might know in order to learn how does a candle burn and what controls the size of the flame. Find out if burning candle is a chemical reaction? Keep track of where you got your information from.

Candle Burning Safety Tips:

1. Candles are a fire hazard if used improperly.
2. Never leave a burning candle unattended.
3. Place on sturdy structure that has a heat-resistant surface away from any flammable sources or any type of draft.
4. Heat of candle’s flame moves up. Make sure there are no flammable objects above the candle.
5. Keep burning candles out of the reach of children, pets or unsafe situations.
6. To prevent any damage to persons, pets or surface discontinue use when 1/2″ of wax remains
7. To protect table surfaces from absorbing candle color, always use a holder.
8. To prevent candles from boring a hole down the middle, burn candles for at least one hour for each inch in diameter. For example burn a 3-inch candle at least 3 hours
9. Candlewicks should be trimmed to 1/4 inch to prevent smoking.
10. Even “non drip candles” may drip under certain circumstances, ie., being placed in a drafty area. If candle appears ready to drip, extinguish candle and allow to cool for approximately one half hour before re-lighting.
11. If candle drips try moving to another location or check air movement that may be causing a draft.

*Place the candle in an area free from drafts. The first time you light the candle, allow it to burn until the liquid wax covers the entire top of the candle. This breaking in process insures that it will perform better and more evenly throughout the life of the candle. For pillars, plan on burning 5-6 hours on the initial lighting. With subsequent use, the candle should remain lit for a minimum of 3 to 4 hours each time. This will insure a clean and efficient burning cycle for the life of the candle.

*To extinguish a candle, dip the wick into the liquid wax, using a non-flammable instrument. This little known technique eliminates smoking

*The wick is designed to produce a small black carbon cap at the top of the wick as it burns. This is normal as it helps radiate heat to the edge of the candle. You should not trim the wick nor touch it while it is cold! After extinguishing the flame, it is best to remove carbon deposits or other foreign materials from the liquid wax when possible.

*Should your candle burn unevenly due to a draft consider this. Carefully push the wick towards the higher side. If this causes dripping, extinguish the flame, let it cool for an hour, then relight the candle. Repeat this practice a few times and the candle will repair itself.

*To regain the color and luster of the non textured candle, buff with a soft cotton cloth or an old nylon to remove dust and small scratches. This process revitalizes the candle’s sheen. The heat from the candle burning tends to dull the finish but it can easily be regained with this simple maintenance tip.

Question/ Purpose:

What do you want to find out? Write a statement that describes what you want to do. Use your observations and questions to write the statement.

The purpose of this project is to identify any change in the mass of candle caused by burning.

Question:

Does candle loses weight when melted down?

Identify Variables:

When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.
Independent variable (also known as manipulated variable) is the burning time.

Dependent variable (also known as responding variable) is the change in the weight of candle.

Controlled variable is the temperature.

Constant is the experiment method, procedures and instruments.

Hypothesis:

Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis.

This is a sample hypothesis:

Candles losses weight when it melts down. My hypothesis is based on my observation of smoke and vapors from a burning candle. This indicates that part of candle is being lost in the form of smoke and vapors.

This is another hypothesis:

The mass of candle does not change during the melt down. The flame of the burning wick melts down the wax; however, melting is not supposed to change the weight.

Experiment Design:

Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”

Experiment: How does the mass of candle material change by burning?

Introduction: We can lit a candle and let it burn in an open container where melted wax remains with the rest of candle. By measuring the initial mass of the new candle and final mass of melted candle we may determine if any change has happened in its mass.

Procedure:

1. Find a small and light base or tray to hold your candle. The lid of a tin can or a piece of cardboard covered by Aluminum foil may be used as the base.
2. Place the base over a larger piece of aluminum foil and fold the surrounding foil upward to form a tray.
3. Measure the weight of the tray and write it in your notes.
4. Place a plain candle in the center of the tray and secure it with some chewed gum or modeling clay.
5. Place the candle with tray over a digital scale. Observe and record the total weight. Deduct the weight of the tray in order to calculate the weight of the candle.
6. Light up the candle.
7. Every 5 minutes measure and record the weight again. Continue until about 3/4th of the candle is melted. After each measurement, deduct the weight of the empty tray and only write the weight of candle in your data table.

Your data table may look like this:

Your data table may have more or less rows depending on the size of your candle.

Make a graph:

You can make a graph to show the changes in the weight or you can make a graph to show the weight loss. Use the horizontal axis for time and the vertical axis for weight. You can either make a bar graph or a line graph.

Experiment pictures:

The candle tray is made of piece of cardboard covered by aluminum foil. Cardboard and aluminum foil are selected because they are both light material and allow us to measure the changes in the weight of candle more accurately.

For this experiment you can use any sensitive gram scale that can measure 1/10th of grams. Most lab scales and Jewelry scales are good for this experiment.

Scales are a good addition to any personal lab. High precision mechanical scales and digital scales are both in the price range of $30 to $60.

If you are not planning to have a personal lab, you may be able to borrow a scale from your school lab for your experiment.

Image in the right shows a triple beam balance scale.

The candle is secured on the tray by masking tape.

You may be also able to find a ready made aluminum plate as the base for the candle. The purpose of such tray or plate is to contain the molten wax. A ready made tray or plate is easier to use as well.

The aluminum plate shown in the right is known as a weighing dish and I got that from a local lab. They usually cost a few cents. Any similar plate or ash tray will do the same.

Ready made plates are especially good if you are using a digital scale.

Picture in the right shows a digital scale that can weigh up to 270 grams. It is generally used by jewelers, small labs and collectors of coins and minerals.

If you are using a digital scale with power save option, you may need to remove the candle from the scale and put it back every time that you turn on the scale again.

Materials and Equipment:

This is a sample list of materials:

• Small digital scale with 0.1 gram accuracy.
• Plain white 6″ candle
• Aluminum foil or small aluminum plate
• Watch or clock

Results of Experiment (Observation):

Experiments are often done in series. A series of experiments can be done by changing one variable a different amount each time. A series of experiments is made up of separate experimental “runs.” During each run you make a measurement of how much the variable affected the system under study. For each run, a different amount of change in the variable is used. This produces a different amount of response in the system. You measure this response, or record data, in a table for this purpose. This is considered “raw data” since it has not been processed or interpreted yet. When raw data gets processed mathematically, for example, it becomes results.

Calculations:

If you do any calculations for this project, write your calculations in this part of your records.

Summary of Results:

Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.

It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.

Conclusion:

Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.

Related Questions & Answers:

What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.

Possible Errors:

If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.

If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.

References:

Visit your local library and find books about candles, candle making, fire and burning, general chemistry and chemical reactions.

List such books and your online references in your bibliography.

Q: All the candles we can find to use are “no drip”. Will the project still work with these?

A: Yes it does. You can also enhance your project by two additional observations.

1. You can hold a porcelain plate or a cup of ice about one foot above the candle and observe the condensation of water. This will show you that part of the candle mass is being converted to water.
2. If you are using a cup of ice-water to observe the condensations, you can also place a thermometer in the cup and observe the temperature increase. In this way you can also show that burning candle creates heat energy. To measure the amount of energy you must know the amount of water in the cup in milliliters. You must also measure the temperature increase in Celsius (or centigrade). By multiplying these values you will get the amount of energy in calories.