Combustion in a Test Tube

Zoris A. Soderberg             Daniel Webster 
                               4055 W. Arthington Street
                               Chicago IL 60624
                               (312)534-6925

Objectives:

To review and enhance vocabulary understanding of words related to the science 
   unit 
To develop and enhance students' understanding of combustion 
To demonstrate that certain things are needed for combustion - especially oxygen
To demonstrate combustion

Materials Needed:

   Dry yeast (2 envelopes), 30 small test tubes, 30 splints (very small wooden
sticks), matches, hydrogen peroxide, test tube holders (30), or clothes pins

Strategy:

   1.  Review the definition of: ignition, combustion, kindling temperature, 
       oxygen, fire and heat
   2.  Pre-measure a small amount of dry yeast (about one eighth of a teaspoon)
       for each of the test tubes.
   3.  Pour the pre-measured amounts of dry yeast into dry small test tubes and
       put them to one side.
   4.  Hold a short discussion with the students about combustion and what is 
       needed to cause combustion.
   5.  At the end of the discussion give each of the students a test tube with 
       the yeast in it.
   6.  Have the students place the test tube inside the test tube holder.
   7.  Quickly check each test tube to see if this has been done correctly
   8.  Have each student pour a small (about 4ml) of hydrogen peroxide (H2O2)
       into their test tube on top of the dry yeast (which reacts very quickly)
   9.  Have the students quickly light the splints and quickly blow out the 
       fire on the splint to a slight glow.  Immediately place the glowing 
       splint into the test tube with the reacting mixture (Do not drop the 
       glowing splint into the test tube).
  10.  Have the students observe what happens (glowing splint should burst back 
       into a flame - not dangerous, but use caution).
  11.  After the demonstration, have the students place used materials on tray.
  12.  Hold class discussion on what they did and saw.

Performance Assessment:

   1.  Upon reviewing the vocabulary words the students will demonstrate their 
       level of comprehension of the words by using them in related science 
       sentences. 
   2.  After doing the demonstration the students will be able to explain 
       what combustion is and what is needed to cause combustion.


Conclusion:

Mixing the peroxide on top of the dry yeast causes the yeast to react thus 
trapping oxygen inside the yeast bubbles.  When the glowing splint is placed 
inside the test tube with the mixture, the splint will burst into a flame 
because of the presence of oxygen because oxygen is the main element in 
combustion. 

References:

Former college instructors.