A Transparent Dust Explosion Apparatus
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Submitted by: G. P. Haight, ,Ir., Robert Duvall, and Stanley Phillips, Department of Chemistry and Chemical Engineering, University of Illinois, Urbana, Ill. 61801 Cheeked by: Willard D. Houston, Ravenna High School, Ravenna, Ohio PREPARATION
Conventional dust explosion apparatus used in lecture demonstrations usually involves opaque metal containers (milk cans) from which lids are blown to great heights.' Faced with the disappearance of milk cans from the dairy scene, the authors conceived the apparatus shown in Figures 1 and 2. A Lucite container equipped with a sparking device and atomizer permits the viewers to see the dust fill the chamber and explode. A paper diaphragm makes the explosion noisy and provides support for another object, such as a styrofoam plastic ball, which is blown high above the lecture table. Figure 1 shows the apparatus ready to fire, and Figure 2 is a detailed drawing of the parts.2
(Dissolve chips of Lucite plastic in ethylene dichloride until a solution having the consistency of syrup is obtained. This cement dries in a few minutes but should set for about 24 hr to gain full strength.) I t is necessary to clean the chamber frequently as the unburned dust has a tendency to stick to the walls and obscure vision.
REMARKS
The bottom of the chamber and one Lucite flange (ring) are attached to the Lucite cylinder wit,h cement.3
' H. N. ALYEAAND F. B. DUTTON,"Tested Demor~strationsin Chemisbry," P~tblishingCo., Easton, Pa., 1965, p. 8. 'Photograph courtesy of t,he Instn~ctionalMaterials Division, Universidy of Illinois, Tirbana. Plastic Sllpplier: Cadillne Plastic Co., 727 W. Lake, Chicago, 111. 60606.
Figure 1
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Journal of Chemical Edlrcolian
. October 1968
COMPLEXES IN RUST SPOT REMOVAL Submitted by: Professor J. PI.Saurer, 41 Rue P.-Jolissaint, St. Immier, Switzerland Checked by: Charlene J. Mchfee, Hiram College, Hiram, Ohio David B. Moss, Wayne State University, Detroit, Mich. PREPARATION
Provide a cloth with rust spots, a very concentrated solution of IIHFI,' FeCI3solution, ICSCN, test tubes. DEMONSTRATION
(1) Using protective gloves, rub the rust spots with a cloth soaked with the KHF? solution. (CAUTION. Handle KHFz with care. Avoid breathing vapors and avoid contact with skin, eyes, or clothing.) Fresh rust spots are removed immediately, older spots require more rubbing.
' Available from Matheson, Coleman, and Bell.
(2) Prepare in each of two test tubes 2 ml of a solution FeCL. (a) Add IlSCN to one test tube aud note the formation of a dark red color. (b) To the other test tube add RHF%in excess, then add IlSCN. No red color appears. REMARKS
In (1) above the Fe(II1) (from rust) is complexed with the fluoride ion to form the stable complex [FeFG]+. In (2b) the fluoride again removes t,he Fe(II1) in forming the complex. Journal of Chemical Eduealion
. Oclobei 1968
Volume 45, Number 70, October 7968
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A833
