States of Matter

Demonstrations for Elementary and Middle School Science Classes

Activities are selected from those below. The chemical test for CO₂ is given higher priority for middle school, but often omitted for elementary school presentations. All of the concepts presented are done in an entertaining way.

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• How many states of matter are there? What are the names and characteristics of each? answer
• Name the property that describes a substance which takes of the volume of its container. answer
• Name the processes of converting between any two phases. answer
• Consider the role that liquids play both in 'seeing' invisible gases and in measuring the volume of both solids and gases.

Plasmas:

• Look at an electrical spark in air.
• Look at CO₂ and neon discharge tubes.
• Look at a fluorescent light bulb.

Liquid Nitrogen (supplies):

• Pour liquid N₂

  

• What is the boiling point of liquid N₂? Guess (Requires JavaScript)
• Break a racket ball
• Shatter a copper clad, zinc penny
• Drive a rubber nail into wood
• Collapse a balloon by condensing air in liquid N₂; liquids occupy a tiny volume compared to the same amount of substance in the gaseous state.

  

• Fractional distillation of air into N₂, O₂ and CO₂ .
  • Videos: Air Condensation | Overview | Nitrogen and Oxygen | Carbon Dioxide
• Explode a rubber glove from evaporating liquid N₂; gasses occupy a huge volume compared to the same amount of substance in the liquid state.

  

• Demonstrate a model of an internal combustion engine. How does an engine take advantage of the difference in properties of a liquid and a gas? answer
• Is there another way to condense a gas besides cooling it off? answer

Dry ice (supplies):

• What is dry ice? answer
• What is the name of the solid to gas transition? answer
• What is the subliming point (like a boiling point or a melting point) of dry ice? Guess (Requires JavaScript)
• Bubble subliming dry ice in water to show escaping gas
• Use dry ice for a bottle rocket
• Properties of CO₂:

  It is a dense gas; therefore it sinks
  It extinguishes flames

• Light short and tall candles in aquarium and let dry ice sublime to put out short then tall candle
• Divert to examine the properties of sinking and floating:
  • Place granite, cork, limestone, wood and pumice in a liquid. Throw a piece of ice into the liquid and observe that it sinks. Why does the ice sink in the liquid? answer
  • Place a can of Coke and can Diet Coke in a deep container of water. Why does the Diet Coke float and the Coke sink? answer
  • Examine a Cartesian Diver, which is an eye dropper filled partly with water, but with enough of an air bubble to make it float in a 2-L plastic bottle. Why does the dropper sink when the capped bottle is squeezed? Does the dropper rise when the pressure released? answers
• Bubble CO₂ from dry ice into a solution of pH indicator which you can get from an aquarium store. Why does the indicator change color? answer
• Bubble exhaled breath in bromocresol blue to see the same color change
• Bubble CO₂ from dry ice in lime water to test for CO₂; watch a white precipitate form and redissolve, an important process in stalagmite and stalagmite formation in caves
• Bubble exhaled breath in lime water to test for CO₂
• Remove candles from aquarium and float air filled bubbles on CO₂: movie
• Light a candle and pour CO₂ from aquarium to extinguish the flame
• Fluid: any state that pours; any state that takes on the shape of its container pours; both gases and liquids are fluids

Other miscellaneous demonstrations with gasses:

• Generate H₂ from Mg and vinegar
• Compare densities of H₂-, CO₂- and butane-filled soap bubbles
• Demonstrate the potato gun
• Liquefy CO₂ from dry ice under pressure (only with very small groups)

Polymers:

• Make a polymer from Elmer's glue, water and Borax
• Describe polymer: monomer, dimer, trimer, tetramer ... polymer
• Viscous liquid, but some properties of a solid
• Demonstrate the water absorbing properties of sodium polyacrylate, the polymer used in diapers
• Demonstrate differences in elasticity of different types of rubber

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