Demonstration Lesson Plans Click Below ! ! :

1. Charcoal Sausage

2.   Burning Water 

3.  Absorption of Heat & Non-Burning Paper Cup

4. The Non-Burning Dollar Bill

5.  Reaction Rates & the "Grain Elevator Explosion"

6. Reaction Rates & the "Light Stick"

Section 1- Chemical
& Physical Changes

Section 2- Chemical
& Physical Properties

Section 3 - Water &
Its Properties

Section 4 - Corrosion

Section 5 - Acids/Bases/In dicators

Section 6 - Gases & Pressure

Bibliography

Appendix 1 -Charts & tables, Disposal of Chemicals, Sources of Chemicals,  Preparations of Acid and Solutions

Appendix 2              Properties of Common Elements, Descriptions of the Elements, Ban Dihydrogen Monoxide

Appendix 3                Principles of Education, Prof. Hanko

The Reformed Witness, Rev. Cammenga

COVENANT HOME

CHEMISTRY HOME

SECTION 1 : CHEMICAL AND PHYSICAL CHANGES

Reaction Rates & the "Grain Elevator Explosion"

Chemical Concept and Topic:

• Chemical Reactions
• Exothermic Reactions
• Everyday life applications
• Surface Area and Reaction Rates

Materials: 

• One plastic funnel
• One medium sized candle
• One plastic "film" container
• One 4 foot section of rubber tubing
• One large coffee can with a lid
• A few spoonfuls of powdered sugar

Set-up Procedure:

1. Drill a ½ inch or a 3/8 inch diameter hole into the bottom of the side of the coffee can.

2. Slide the hose through the hole. Connect the hose to the end of the funnel. Pull any slack hose inside the coffee can out of the can through the hole.

3. With some caulking (I actually use "play-dough" and it has worked well) cover around the hole so that there are no air gaps between the hose and the edges of the hole.

Demonstration Procedure:

1. Place one or two spoonful of powdered sugar into the funnel. Make sure that the powdered sugar lies over top of the hole in the funnel.
2. Light a candle and place it directly in front of the funnel. (See Figure 1.)
3. Turn out the classroom lights and close the blinds.
4. Un-tangle the rubber hose and be prepared to blow into the hose.
5. Very quickly, place the lid on the coffee can and make sure it sealed well, step back a stride or two, and blow one long large breath of air into the hose.
6. Observe. The results should occur in dramatic fashion. (See Figure 2.)

Questions:

1. What happens to a sugar cube when you try to burn it? Try it.
2. What accounts for the fact that powdered sugar in the coffee can got a lot different result than a pile of powdered sugar or a sugar cube would have had?
3. What is surface area?
4. What is the relationship between surface area and reaction rates?

Explanations:

1. When one tries to burn a pile of powdered sugar or a sugar cube, the sugar will burn and turn black but it does so in a very slow and difficult manner.
2. The powdered sugar in the coffee can was blown into the air inside the coffee can. As this happened the particles of sugar were spread apart from each other and the "surface area" of the sugar was increased. This permitted each particle of sugar to burn simultaneously, producing a large ball of fire.
3. Surface area refers to the amount of area of a particle that is exposed to the flame or other chemicals in which it needs to react. In a sugar cube, 3 cm by 3 cm by 3 cm, all the sugar particles are packed into a cube so that the amount of sugar actually "exposed" to the air is only the sugar particles that are on the edge of the cube. All the inner particles are not "exposed". The actual surface area of this cube would be: 6 sides times 9 cm² (area per face) = 54 cm²
4. If the cube would be crushed and every single sugar crystal was set on a table next to another sugar crystal, the surface area (the amount of sugar exposed to the air) would dramatically increase.
5. A reaction will occur more quickly if the reactants have a greater surface area. In this case, the powdered sugar was forced to increase its surface area, because the demonstrator blew the particles into the air. This increased surface area increased the rate of reaction and a violent reaction was observed.

This demonstration can be applied to everyday life. Grain elevators receive grain from the farmers. This grain is stored in the grain elevator. As the grain is unloaded from the farmer into the grain elevator the grain is moved around so much that a lot of grain dust forms. The surface area of the grain is increased greatly. Therefore, a cigarette or an electrical spark in a grain elevator acts like the candle in our demonstration and ignites the grain dust. This results in a rapid burning of the grain dust, forming a huge fireball and a costly explosion.

Reference: Zwart, John. Physics Department Dordt College. Sioux Center, IA, 1992.

The Federation Board of the Protestant Reformed Christian Schools commissioned Joel Minderhoud to develop this Repertoire of Chemical Demonstrations

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