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Reprinted by permission of Dick Berg, University of Maryland, for use on this website.

The demonstrations contained and referenced herein are listed for the purposes of cataloging and describing physics demonstrations which should be conducted only under the direction of a trained instructional support professional or physicist. These demonstrations are not presented for the purpose of being conducted by persons unconnected to this Facility and/or persons not consulting with or being supervised by the recognized instructional support professional or physicist and his/her staff. The University is responsible only for those demonstrations carried out using its own equipment using established safety and scheduling policies, and bears no responsibility for those choosing to use this source material for their own purposes. All demonstrations described and contained herein are public domain, and can also be found in reference materials in libraries, bookstores, and electronic sources.

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Dissolve the shell off of several eggs with the vinegar.  This will take at least 12 hours.  Compare the naked egg to a regular egg with a shell and notice the dramatic increase in size.  This increase is due to absorption of water through the permeable membrane.

Prepare two beakers, one with salt water and one with plain water.  Cut some 1/4" slices from a potato and drop into each beaker.  Wait 20 to 30 minutes.  Pull the slice out of the plain water and observe that it does not bend easily and will in fact break crisply.  Do the same to the slice in the salt water and observe that is bends quite readily and is very hard to break.  This is due to the movement of water from the potato cells to the salt water.

Place the raisins in a beaker of plain water and let stand overnight.  Compare regular raisins to the soap raisins.

Take one of the naked eggs and place into a beaker of corn syrup and let stand overnight.  The egg will lose water to the corn syrup and will come out looking much like a large raisin.

Make a saturated solution of corn starch and place about 4 oz of this into the Hy-Vee sandwich bag.  (These bags work well because they will hold water without leaking but will allow gas or small atoms to pass through). Put about 300 ml of water in a beaker and place about 20 to 30 drops of iodine into this.  The water will remain clear or will have a slight yellow tint.  Place the sandwich bag into the iodine water and after 1/2 hour observe that the starch inside the bag is turning dark blue or black.  As a check you can add several drops of iodine to the starch solution and observe a very dark blue color.