Once the candle is burning, the flame of the candle melts more wax which rises up by capillary action through the wick. At the top of the wick, it is further heated to become a gas. The gaseous wax is also ignited by the existing flame. The process becomes self-sustaining. When you hold a fire source to the wisps of smoke, they can reignite and cascade back to relight the candle!
The trail of smoke released by the piece of wood does not contain fuel. The three conditions necessary for combustion form the basis for using fire extinguishers to quench fire. Most fire extinguishers contain carbon dioxide gas or chemicals that smother the fire. That is, they form a layer of foam or powder on the fire that cuts off the fuel from the oxygen supply around it thus putting out the fire.
Remember, oxygen supports burning. Fuel is needed to make a fire. So, with the two effectively separated, burning can no longer take place. Fire extinguishing. One of the conditions necessary for combustion is eliminated for the fire to stop. Please use the hashtag FundiAtHome and tag our social media accounts fundibots so we can see your awesome experiments and have other people join the discussion!
Experiment Re-lighting A Candle. A typical flame, such as that from a candle, produces light, heat, carbon dioxide and water vapor. The heat causes these combustion products to expand, which lowers their density, and they rise due to buoyancy. Fresh, oxygen-containing air can thus get into the flame, further fueling the combustion process.
Because gravity is necessary for density differences to arise, neither buoyancy nor convection occur in a zero-gravity environment such as space. Consequently, the combustion products accumulate around the flame, preventing sufficient oxygen from reaching it and sustaining the combustion reaction.
Ultimately the flame goes out. In the early years of the U. Researchers learned that flames extinguish themselves. They ran these experiments because they hoped to have an oxygen environment for manned missions and there was concern about the possibility of a rampant fire. Unfortunately, in fire broke out in the Apollo I spacecraft while it was still on the ground and three astronauts were killed.
The flames didnt self-extinguish because the launch pad was not a gravity-free environment. Background Whether they are on a birthday cake or dinner table or menorah, most candles we use today are wax-dipped candles. This style of candle dates back to the ancient Romans. Through the center of the wax runs a wick, which is usually made from cotton or other material that can absorb liquids well.
So how do these two materials come together to help a candle burn steadily? A lit candle might seem simple, but it is actually an example of a multi-step process resulting in combustion—and the glowing flame you see. Combustion is the result of a chemical reaction in which oxygen gas reacts with the substance that is being burned.
The combustible material in a candle—or its fuel—is the wax. But before the wax can become fuel it first needs to get hot enough. To start that heating process, you first need to light the wick with another source of fire, such as a match.
As the wick burns down the heat of the flame melts the wax around the wick. Because the wick is absorbent it sucks the liquid wax into the wick and upward into the flame. Once the liquid wax gets hot enough, it then turns from a liquid into a gas. The hot gas then reacts with the oxygen from the air and is burned, creating the candle flame that we see.
This means that the candle flame is actually created by the burning wax gas—or vapor—and not by the wick itself or the solid or even liquid wax. After lighting a candle, it might flicker or sputter at first, but then it usually burns fairly steadily.
As the heat of the wax vapor flame melts more of the solid wax it creates more fuel for the flame to burn. The candle will only go out once it runs out of wax or oxygen—or gets blown out. After a candle goes out you can actually see the wax vapor escaping as a stream of white smoke. If you hold a match into that smoke, the candle will catch fire again—without even touching the wick! Don't believe it?
Then try this activity to see for yourself! Observations and Results Could you make a candle's flame jump from one candle to another? The first time you lit your candle you most likely had to touch the wick with the flame of your match. This makes the wick catch fire, which starts the combustion reaction. The wax around the wick starts melting, and it is from this liquid wax that vapor is created inside the flame.
The wax vapor starts to burn and creates the stable candle flame that you see. When you blew out the candle you should have seen white smoke rising up into the air from the wick. This is the wax vapor, which becomes visible as it condenses into small liquid droplets in the cooler air. If you touched the wax vapor white smoke with another flame, the candle should have immediately lit up again. This time you didn't even have to touch the wick or another part of the candle.
Lighting the vapor is enough to get the candle burning again. When you placed two or more candles next to each other and blew one out the burning candle's flame should have reignited the wax vapor of the extinguished one. You might have realized that it is actually quite hard to keep a candle extinguished when it is so close to a burning one.
It lights up again due to the fact that the wax vapor of the blown-out candle is touching the remaining candle flame. What you end up seeing is the candle flame jumping from one candle to another!
Cleanup Make sure to extinguish all your candles at the end of your experiment.
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