Gel Synthesis

Materials:

•1/4 oz packet of Knox Gelatin (1)

•Microwavable glass container (1)

•Water

•50 mL graduated cylinder (1)

•10 mL graduated cylinder (1)

•A container for the gel to develop in (1)

Recipe for Making Gel (student’s version):

Caution! Overheating and/or using the wrong container (particularly metal) in a microwave could start a fire.

•Obtain a 1/4 oz packet of Knox brand gelatin, and place it in a large container.

•Mix the Knox gelatin with water, taking care to record the amount of water used. 

•Stir the solution for one minute.

•Microwave the solution until it boils.  Be careful not to use a shallow container because the solution will foam as it boils.  Heating the Knox powder-water mixture breaks down any large molecules created by the Knox powder with the water.

•Pour the hot solution into a container.  Label the container with the amount of water used to make the solution so you can keep track of the solution's concentration.

•Place the container in a refrigerator and leave untouched for an hour (or 1.5-2 hours if the water concentration is large).  Careful!  Make sure that the surface on which the samples sit is level.  Otherwise your samples will be slightly tilted and your data based on Brewster's angle will be incorrect.

•In order to remove the gel from its container, place container in warm water. (Careful: Do not allow the water to touch your gel sample unless you want to change the water content of the gel sample.).  The gel will literally slide out once the container is warm enough.  Too much heat will cause the gel to become mush.

 

Perform the following two experiments for several gelatin concentrations.  Namely, add a packet of Knox to different amounts of water (such as 1 cup, ½ cup, ¼ cup, etc).

 

For a more detailed gel-making recipe, click here (instructor's version).

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