States of Matter
To observe and understand the changes in states of matter (solid, liquid, gas) by heating and cooling water in a controlled lab environment.
Materials Needed:
- Beakers
- Water
- Bunsen burners
- Tripod stands
- Wire gauze
- Ice cubes
- Thermometers
- Tongs
- Safety goggles
- Lab gloves
Procedure:
- Observing Melting (Solid to Liquid):
- Place a few ice cubes in a beaker.
- Observe and record the characteristics of ice in its solid state.
- Set up the tripod stand and place wire gauze securely on top of the stand.
- Place the beaker with ice cubes on the wire gauze.
- Light the Bunsen burner, adjust it to a low flame, and position it under the gauze to gently heat the beaker.
- Carefully observe the ice as it begins to melt, transitioning into a liquid state.
- Use the thermometer to measure and record the temperature at which the ice melts.
- Observing Evaporation (Liquid to Gas):
- Once all the ice has melted into water, adjust the Bunsen burner to increase the flame.
- Observe the water as it heats up and eventually starts to boil, turning into steam (gas).
- Use the thermometer to record the temperature at which the water boils.
- Observing Condensation (Gas to Liquid):
- Hold a cool, metal object (like the back of a spoon or a metal plate) above the steam coming from the boiling water.
- Observe the formation of water droplets on the metal object, indicating the condensation of steam back into liquid water.
- Observing Freezing (Liquid to Solid):
- Allow the water in the beaker to cool down to room temperature.
- Pour the water into a clean beaker or an ice tray and place it in a freezer (or a cold area if a freezer is not available).
- After a few hours, check to observe the water frozen back into ice, indicating the transition back to a solid state.
Safety Precautions:
- Always wear safety goggles and lab gloves when handling hot equipment and chemicals.
- Handle the Bunsen burner with care, and ensure it is turned off after the experiment.
- Use tongs to handle hot beakers or leave them to cool.
Discussion:
- Discuss the changes in states of matter and the temperatures at which these changes occur.
- Explain the physical processes involved in each state change, including molecular motion and intermolecular forces of attraction.
- Relate the experiment to the principle of conservation of matter, noting that water changes its state but not its mass.
Practical Science 