O2+vs+CO2+-+How+to+Make+a+Candle+Burn

= O2 vs. CO2: How to Make a Candle Burn = Lesson Plan for Clinic 2 Brittany Buterbaugh - __ __blb302@psu.edu__ __ Kristen Park - __ __klp258@psu.edu__ __ Grade Level: 7 th grade

PA Standards: 3.4.7.A: Describe reactants and products of simple chemical reactants. 3.2.7.C: Communicate appropriate conclusions from the experiment 3.2.7.C: Judge the significance of experimental information in answering the questions

National Standards: Content Standard B: Physical Science: "Substances react chemically in characteristic ways with other substances to form new substances (compounds) with different characteristic properties. In chemical reactions, the total mass is conserved. Substances often are placed in categories or groups if they react in similar ways; metals is an example of such a group."

__Objectives__ : 1. Students will be able to explain how O 2  promotes combustion. 2. Students will be able to explain how adding/forming CO 2  will stop the process of combustion. 3. Students will be able to explain the formation of CO 2  gas from a simple acid/base reaction.

__Content Explanation__  The main idea of this lesson is to help the students understand combustion. When the candle is burning, there must be enough oxygen for the flame to continue to burn. Once there is no longer enough oxygen to sustain the flame, the flame will go out. If the flame is overwhelmed with CO 2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">gas, the flame will go out. Dry ice will form CO <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 6.6pt; text-decoration: none; vertical-align: sub;">2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"> gas at room temperature. By pouring this CO <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 6.6pt; text-decoration: none; vertical-align: sub;">2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"> gas into a trough containing candles, the candles will stop burning due to lack of oxygen. A similar result will happen if the candle is introduced into an environment where CO <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 6.6pt; text-decoration: none; vertical-align: sub;">2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"> is being produced. A reaction with vinegar and baking soda will produce CO <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 6.6pt; text-decoration: none; vertical-align: sub;">2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"> gas and also put out a candle flame.

Administrative Concerns

Safety:
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">Candle-open flame which is a safety concern
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">Acid/base reaction-can be violent and is a safety concern
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">students will need to wear safety googles while observing this demonstration
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">Dry ice- could cause burns due to extreme cold

<span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"> Classroom management:
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">students will need to be kept away from the open flame so that they do not burn themselves
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">however, students will need to be near enough to the demo so that they can observe when the candle goes out

<span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">Materials, Equipment, and Set-up
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">candles (6)
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">matches (a big box)
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">2 liter bottles of soda with the top cut off (2)
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">vinegar
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">baking soda
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">V-shaped trough
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">Wire coat hanger (to lower lit candle into bottle)
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">Dry Ice
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">2-liter beaker
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">cardboard to cover 2 liter beaker

<span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"> Equipment is the wire hanger that will be used to lower the burning candle into the 2 liter bottle as well as a trough that will hold five candles that will be extinguished by pouring the gaseous CO <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 6.6pt; text-decoration: none; vertical-align: sub;">2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"> over them.

Before the lesson is begun a piece of dry ice will need to be placed into a 2 liter beaker and allowed to sublime. Extreme care will need to be taken with the dry ice as it could cause burns.

Body of Lesson:

Predict (7 minutes): Ask the students how a candle burns. Show them the chemical reaction for the combustion of a candle. (1)Ask the student what they think will happen if we place a lit candle in a beaker and cover it with foil or cardboard. (2)Ask what would happen if we replaced the oxygen with another gas. Have them write their predictions on a piece of paper and share what they think will happen. Then talk about the acid/base reaction of vinegar with baking soda and how it produces CO <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 6.6pt; text-decoration: none; vertical-align: sub;">2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"> gas. Ask the students what they think will happen to the candle if lowered into the reaction producing CO <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 6.6pt; text-decoration: none; vertical-align: sub;">2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"> gas. (Try to get students to think about touching the liquid part of the reaction vs. it not touching the liquid part of the reaction.) Have them write down their predictions. (3)Finally, have the students predict what will happen if CO <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 6.6pt; text-decoration: none; vertical-align: sub;">2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"> gas is poured from a flask containing dry ice into a container with 5 smaller candles.

Observe (7 minutes): (1)First, a lit candle will be placed into an empty beaker, and the beaker will then be covered. The students will observe the candle extinguishing. <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">(2)A lit candle will be lowered in an empty beaker. The students will observe the candle still burning. The candle will be removed from the bottle and allowed to sit lit on the table AWAY from the students as this open flame is a SAFETY CONCERN. Vinegar will then be poured into the beaker and a teaspoon of vinegar will be added. During the reaction of acid/base mixture, which is producing CO <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 6.6pt; text-decoration: none; vertical-align: sub;">2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">gas, the candle will be quickly lowered into the beaker (do not allow it to touch the liquid mixture), and students will be able to observe the candle being extinguished. <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">(3)At this point the five candles in the trough will be lite and the students will be asked what they think will happen if gaseous CO <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 6.6pt; text-decoration: none; vertical-align: sub;">2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">is added to one side of the trough. The students will observe the candles slowly going out one by one as the CO <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 6.6pt; text-decoration: none; vertical-align: sub;">2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">diffuses across the trough.

<span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">Explain (6 mintues): The students will discuss what they observed in groups and will then provide an explanation to the instructor. Each group will state in one or two sentences what they thought happened and at the end the instructor will provide the correct reasoning. (1) The candle extinguished because the oxygen was being used up and CO <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 6.6pt; text-decoration: none; vertical-align: sub;">2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;">was being produced. (2) The candle is extinguished due to the production of CO <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 6.6pt; text-decoration: none; vertical-align: sub;">2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"> gas that is forming in the beaker from the baking soda/vinegar reaction. This takes the place of the oxygen which was keeping the flame burning. (3) The candles are extinguished one at a time from the end closest to where the CO2 is poured into the container. This happens due to the diffusion of the CO2 gas throughout the container. As the CO <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 6.6pt; text-decoration: none; vertical-align: sub;">2 <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; text-decoration: none; vertical-align: baseline;"> reaches the candles, they go out.