Dissolved Substances in Tap Water and Seawater
Contributors
Summary
The experiment "Dissolved Substances in Tap Water and Seawater" involves students evaporating tap water, distilled water, and seawater to observe solid residues. They also witness an instructor-led demonstration where gases are released from boiling these waters, collected, and tested. This practical activity helps illustrate the different dissolved substances in various water types, showcasing solubility, evaporation, and gas collection concepts.
Safety Precautions, Hazards, and Risk Assessment
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Teacher Recommendations or Piloting Data (if available)
Distilled water should contain no dissolved solids, tap water some dissolved solids (those causing ‘hardness’, for example), and seawater should have more dissolved solids (sodium chloride and other salts). A related experiment describes how to analyse the salts obtained from seawater.
The gas that comes out of both seawater and tap water is air (with a higher percentage of oxygen than normal air, as oxygen is more soluble than nitrogen). The best test available would be to show that a glowing splint continues to glow and does not immediately go out when placed in the gas.
The presence of dissolved oxygen in water is, of course, vital for fish to survive.
The gas that comes out of both seawater and tap water is air (with a higher percentage of oxygen than normal air, as oxygen is more soluble than nitrogen). The best test available would be to show that a glowing splint continues to glow and does not immediately go out when placed in the gas.
The presence of dissolved oxygen in water is, of course, vital for fish to survive.
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