A phase change is a change in the states of matter. For example, a solid may become a liquid. This phase change is called melting. When a solid changes into a gas, it is called sublimation. When a gas changes into a liquid, it is called condensation.

The most obvious physical properties of a liquid are its retention of volume and its conformation to the shape of its container. When a liquid substance is poured into a vessel, it takes the shape of the vessel, and, as long as the substance stays in the liquid state, it will remain inside the vessel.

Solids are not fluid, but liquids share a different important property with them. Liquids and solids are both held together by strong intermolecular forces and are much more dense than gases, leading to their description as “condensed matter” phases because they are both relatively incompressible.

Explanation:

• A solid has a definite shape and volume.
• Solids in general have higher density.
• In solids, intermolecular forces are strong.
• Diffusion of a solid into another solid is extremely slow.
• Solids have high melting points.

The particles make up matter are atoms or molecules.

• The particles of matter are very, very small.
• The particles of matter have spaces between them.
• The particles of matter are constantly moving.
• The particles of matter attract each other.

Properties of liquid

• Liquid has definite volume.
• Liquid has no definite shape.
• Liquid gets the shape of container in which it is kept.
• Liquid cannot be compressed much.
• Liquid has less density compare to solid.
• Liquid is lighter than solid.
• Liquid flows and hence is called fluid.

Dry ice is solidified carbon dioxide. It is named so because it looks like ice and is way colder than ordinary ice. It stays dry because it directly converts to gaseous carbon dioxide without an intermediate liquid stage. Hence it is useful in storing edible things like ice cream which may get spoilt by water.

Dry Ice is manufactured by compressing and cooling gaseous CO2 under high pressure to initially produce liquid CO2. Due to its extremely low temperature of -78°c, dry ice is often used as an alternative to refrigeration for foodstuffs and medical supplies.

carbon dioxide

Dry ice has just one ingredient: carbon dioxide. Technicians create dry ice by pumping liquid carbon dioxide into holding tanks, which reduces the temperature to -109° F and pressurizes the substance into solid blocks or pellets.