Spinning Jet Stream

Written by: Casey Rogers (ChemDemo) on July 27, 2012.

In this demo a ping pong ball with a hole along the seam is submerged in liquid nitrogen (-196⁰C) to fill it. When removed, the nitrogen in the ball boils and is forced out of the hole in a stream. The stream, which comes out at an angle, causes the ball to spin away from the stream. The “stream” that we see is condensed water vapor, not nitrogen gas.

Liquid Nitrogen Ice Cream

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Written by: Casey Rogers (ChemDemo) on July 21, 2011.

Liquid nitrogen is -196˚C and quickly freezes the ingredients into ice cream. The nitrogen boils out leaving deliciously creamy ice cream. The “fog” that we see is condensed water vapor though, not nitrogen gas.

Shrink A Balloon

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Written by: Casey Rogers (ChemDemo) on June 14, 2011.

When a balloon is placed in liquid nitrogen the air inside it is condensed from the cold (-196°C), causing the balloon to shrink. Once the balloon is removed it will regain its size as the air heats up. Liquid nitrogen boils at room temperature. The “fog” that we see is condensed water vapor though, not nitrogen gas.

Shatter a Flower

Written by: Casey Rogers (ChemDemo) on June 14, 2011.

When a flower is dipped in liquid nitrogen (-196°C) it is instantly frozen. Liquid nitrogen boils at room temperature. The “fog” that we see is condensed water vapor though, not nitrogen gas.

Mushroom Cloud

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Written by: Casey Rogers (ChemDemo) on June 14, 2011.

When dry ice is placed in warm water it sublimes very quickly forming a large amount of carbon dioxide gas. When a bubble is placed over this the bubble grows from the pressure.

Dry Ice in Universal Indicator

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Written by: Casey Rogers (ChemDemo) on June 13, 2011.

Universal indicator goes from red (pH 4) to violet (pH10) as the pH of a substance changes. Adding NaOH to water starts the solution off at pH 8-9 (blue). When dry ice is added to water it forms carbonic acid, and lowers the pH, which is the reason for the color changes. The “fog” that we see is condensed water vapor though, not carbon dioxide gas.

CO2 Bubbles

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Written by: Casey Rogers (ChemDemo) on June 8, 2011.

CO2 gas from subliming dry ice gets caught in a soapy solution creating a column of bubbles. When the bubbles are popped, the “fog” that we see is condensed water vapor, not carbon dioxide gas.