An activity that can demonstrate the existence of particles of matter in three states (solid, liquid, and gas) is the melting and freezing of a substance. You can use water as an example, as it readily undergoes these phase transitions at accessible temperatures. Here's a simple demonstration:
Materials needed:
- Ice cubes (solid state)
- A heat source (e.g., stove or hot plate)
- A pot or container
- Thermometer (optional but helpful)
Instructions:
- Start with the ice cubes in a container. This represents the solid state of water.
- Observe and describe the properties of the ice cubes. Note that they have a definite shape and are rigid.
- Apply heat to the container, either by placing it on a heated surface or using a stove or hot plate.
- As the ice cubes absorb heat, they will start melting and turning into liquid water. Observe and describe the changes that occur. Note that the water now takes the shape of the container but still maintains its volume.
- Continue heating the liquid water. You can use a thermometer to monitor the temperature if available. Eventually, the water will reach its boiling point (100 degrees Celsius or 212 degrees Fahrenheit at standard atmospheric pressure).
- As the water boils, it will convert into steam, which represents the gaseous state of water. Observe and describe the changes that occur. Note that the steam fills the container, expands, and can no longer be contained easily.
- If you have a lid or cover for the container, you can place it on top to capture the steam briefly, demonstrating the gaseous state being confined.
By observing the melting of ice into water and the subsequent boiling of water into steam, you can illustrate the transition of particles of matter from solid to liquid to gas. It showcases how the arrangement and motion of the particles change as the substance undergoes different states of matter.