1. Bouncing Putty

• A ball of silicone rebounds to a great height when bounced off the ground, whereas Plasticine does not.
• A rapid blow with a hammer will barely deform the silicone ball, but will flatten the Plasticine.
• When a length of silicone is quickly pulled apart, it breaks cleanly into two pieces. However, if the silicone is pulled apart so slowly that it does not tear, it will stretch very far.
• When the silicone ball is bounced off the ground, the “flubber” effect is seen again.
• Time-lapse photography shows how the silicone ball flows over a clock like honey. (It is reminiscent of a similar painting by a famous surrealist artist.)
  

Note: For a discussion and explanation of these observations, see the "Viscoelasticity" experiment.

2. Combustion of Silicone Rubber and Natural Rubber

• A metal plate supporting a piece of natural rubber and a piece of silicone rubber side by side is heated with a Bunsen burner.
• The rubber soon starts to decompose (vapors are emitted). The silicone rubber does not decompose.
• On further heating, the natural rubber changes shape and color and eventually catches fire. Silicone rubber does not change initially and only after prolonged heating does it leave marks on the plate. It does not burn.
  

Note: For a discussion and explanation of these observations, see the experiment "Flammability of silicones in comparison with other polymers".

3. Combustion of Silicone Fluid and Paraffin Oil

• A metal plate is heated strongly with two Bunsen burners. A drop each of paraffin oil and silicone fluid are allowed to fall onto the heated areas.
• The paraffin oil ignites immediately and burns quickly with an orange flame. The silicone fluid does not ignite initially.
• Only after a long time, when the plate has become very hot, does the silicone fluid ignite and slowly burn with a dazzling flame.
• Whereas the paraffin oil does not leave any residue behind on the plate after combustion, the silicone fluid leaves a white solid (silicon dioxide) behind.

Note: For a discussion and explanation of these observations, see the experiment "Burning of liquid silicones"

4. Impregnation of Aerated-Concrete Brick

• Drops of water are pipetted onto aerated concrete bricks, one treated with silicone fluid, and the other untreated.
• Whereas the water seeps into the untreated brick, it runs off the brick rendered water-repellent with silicone fluid.

Note: For a discussion and explanation of these observations, see Variant A and Variant B of the "Hydrophobic properties of silicone fluids" experiment.

5. Antifoams 1

• A soap solution in two glass beakers is stirred. When the stirrer has been turned off, a layer of foam is seen in both beakers.
• Some antifoam agent is now pipetted into one of the beakers. The foam collapses.
• The contents of both beakers are stirred again. The soap solution containing the antifoam will not foam even when stirred vigorously.

Note: For a discussion and explanation of these observations, see the "Silicones as antifoams" experiment.

6. Antifoams 2 (Paper Clip)

• Tweezers are used to carefully place a paper clip on the surface of distilled water in a container. The paper clip floats on the water.
• Distilled water is added dropwise from a pipet. The paper clip continues to float.
• Drops of soap solution are now added. After just a few drops, the paper clip sinks.
• The experiment is repeated. Instead of soap solution, drops of a mixture of soap solution and silicone antifoam agent are added. After a few drops, the paper clip sinks to the bottom of the container.

Note: For a discussion and explanation of these observations, see the "Silicones as antifoams" experiment.

7. Hydrolysis of Chloromethylsilanes

Preparation

• 6 test tubes (TT) in a rack are filled as follows:
• TT No. 1: 4 ml distilled water
• TT No. 2: 8 ml distilled water
• TT No. 3: 12 ml distilled water
• TT No. 4: 1 ml chlorotrimethylsilane
• TT No. 5: 1 ml dichlorodimethylsilane
• TT No. 6: 1 ml trichloromethylsilane

Procedure

• The contents of TT 1 are poured into TT 4. A reaction occurs and the solution turns hazy. After the solution has been left for a long while, two clear liquid phases separate out; the volume of the upper layer is smaller than the lower one.
• The contents of TT 2 are poured into TT 5. A violent reaction occurs and the solution turns hazy. Two clear liquid phases separate out fairly rapidly; the volume of the upper layer is smaller than the lower one.
• The contents of TT 3 are poured into TT 6. A violent reaction occurs and the solution turns very hazy. A white solid has formed.
• Some liquid from the lower phases in TT 4 and TT 5 and from the liquid phase of TT 6 is pipetted onto separate strips of indicator paper. Each strip turns red.

Note: For an explanation and discussion of these observations, see the experiments "Hydrolysis of chloromethylsilanes" and "Rate of hydrolysis of chloromethylsilanes".