To demonstrate that matter is conserved during a physical change, you could conduct a simple experiment using a closed system. One effective procedure involves measuring the mass of a substance before and after a physical change, such as melting, dissolving, or evaporating.
Procedure to Demonstrate Conservation of Matter
Materials Needed:
- A closed container (such as a sealed plastic bag or a jar with a lid)
- A solid substance (e.g., ice cubes or a solid salt)
- A balance (scale) for measuring mass
- Water (if using solids that dissolve)
- Thermometer (if necessary for temperature control)
- A stirring stick (for dissolving)
Steps:
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Measure the Initial Mass:
- Weigh the closed container (ensure it is empty and dry).
- Add the solid substance to the container (e.g., ice cubes) and weigh the container with the substance.
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Conduct the Physical Change:
- For melting: Place the container with ice cubes in a warm environment until they melt. Keep the container closed to prevent any loss of water vapor.
- For dissolving: Add a measured amount of solid salt to water in the closed container and stir until it dissolves. Keep the lid on to prevent evaporation.
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Measure the Final Mass:
- After the physical change is complete, weigh the closed container again with the resulting substance (water, solution, etc.).
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Calculate the Mass:
- Record the initial and final masses.
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Analyze Results:
- Compare the initial mass of the container and solid with the final mass. According to the law of conservation of mass, the total mass before and after the physical change should be equal, demonstrating that matter is conserved during the process.
Conclusion:
By keeping the system closed, you can account for all materials present before and after the physical change, confirming that the mass remains constant, illustrating the principle of conservation of matter.
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