Name:
Lab Partner(s):
Per:
Date:
Chemistry in Context - The Burning Candle Lab
Introduction
Why does a flame burn? This lab will test your skill at observation as you investigate the seemingly
simple process of a candle burning.
Observation is an important part of science but is often misunderstood by beginners. Many students
believe that “observing” is the same as “seeing”. However, observing is much more than seeing.
For example, at the scene of an accident different witnesses will often give different testimony as
to what they saw. The witnesses all saw the same thing, but some are more observant than others.
This lab consists of a simple system--a burning candle. You have undoubtedly seen a burning candle
many times before. In this lab, you will observe the candle.
Pre-laboratory Assignment
Read the ENTIRE lab procedure and then answer the pre-lab questions.
1. How are you supposed to secure the burning candle so that it does not fall over onto the
bench top?
2. How many observations are you to make of the burning candle?
3. What are you to do with the 250 mL beaker in Part 3?
4. What are you to do with the 400 mL beaker in Part 4?
5. In Part 5, how far away from the wick are you to hold the burning splint after the candle is
blown out.
Materials
1 candle
3”x5” index card
matches
250-ml beaker
Safety:
400-ml beaker
wood splint
copper wire
Tie back hair and loose clothing. Do not drop matches into the sink.
Procedure and Observations
Part 1. Teacher demonstrations
a. Your teacher will show you an oil lamp.
i.
What is the fuel?
Unit 1A. Burning Candle Lab
1
ii. Is liquid lamp oil flammable? Explain.
b. Your teacher will burn a 1” piece of string. Record how long it burns:
Part 2. The unlit/burning candle
a. Light a candle. Drip some wax onto a 3” x 5” card and stand the candle in the melted wax.
Hold the candle upright until it can stand alone.
b. Observe the UNLIT candle and record as many observations a you can (at least 5).
1.
5.
2.
6.
3.
7.
4.
8.
c. Light the candle and observe the burning candle. Record as many observations as you can
during the next 5 minutes. Observe and record what happens when you put out the candle (to
avoid blowing wax all over, cup you hand behind the candle when you blow it out, or snuff out
with wet fingertips). Use all your senses! Be sure to notice how many states of matter are
present while the candle is burning. You should have at least 10 observations.
1.
7.
2.
8.
3.
9.
4.
10.
5.
11.
6.
12.
Unit 1A. Burning Candle Lab
2
Part 3. The 250-mL beaker
a. Lower a clean, dry 250-ml beaker, right side up, into the candle flame, and
hold it there for a moment. The candle flame should just touch the bottom
of the beaker.
b. Record your observations:
Part 4. The upside-down 400-mL beaker
a. Hold a clean, dry 400-ml beaker upside down over the burning candle.
b. Locate the flame just inside the mouth of the beaker so that it will continue to
burn. Hold the beaker at this height for a few seconds, and note the appearance
of the material, which collects on the sides of the beaker.
c. Record your observations:
Part 5. The smoldering splint
a. Light the candle, and allow it to burn for 1 minute.
b. Hold a wood splint in the candle until it catches on fire, then hold the burning
splint away from the candle.
c. Blow out the candle with a short puff of breath and immediately hold the burning
splint about 2” from the wick in the smoke rising from the candle.
d. Record your observations:
Part 6. The Wire Mesh
a. Burn your candle for 1 minute.
b. Take the square of wire mesh out of your lab desk drawer.
c. Slowly lower a portion of the mesh with holes, not the solid center of the mesh, down over the
wick and flame of your candle.
d. Slowly raise the mesh up and down in the flame.
e. Record your observations:
Unit 1A. Burning Candle Lab
3
Cleaning Up
a. Place the dirty 200 mL and 400 mL beakers on the dirty glassware cart and obtain clean ones
from the storage cabinet.
b. Return all materials as instructed.
c. Wipe down your lab bench.
Analysis and Conclusions
a. Name four things a burning candle produces.
b. When the candle is lit, what is the main fuel, the wax or the wick? Support your answer with
observations.
c. When the candle is lit, what state of matter (solid, liquid, or gas) do you think is actually
burning? Explain. Hint: answer these questions. What happens when you try to light the
bottom of a candle? What happens when you heat a liquid? Think about the lamp oil candle
your teacher demonstrated, and whether the liquid lamp oil burned.
d. Develop a hypothesis that explains what happened when you placed the burning splint in the
smoke. Hint: What are the three ingredients you need for a fire? What is the fuel in a
burning candle? What state of matter is the fuel?
e. Develop a hypothesis that explains what happened when you placed the copper coil over the
flame. Hint: what happened to the temperature of the copper wire? What happened to the
fuel for the burning candle?
f. Develop a hypothesis that explains the role of the wick. Hint: what does the verb “wick”
mean?
Unit 1A. Burning Candle Lab
4