Solids, Liquids And Gases. Flashcards
What is a particle?
Particle theory can explain the properties of solids, liquids and gases. This theory says that all things are made up of tiny pieces called particles. Solids, liquids and gases have different arrangements of particles. This gives them their special properties.
What are the particles like in a solid?
Solids have particles that are close together. The particles are fixed in a place and cannot swap places with each other. This is why solids have a fixed shape.
What are the particles like in a liquid?
The particles in a liquid are still attached to one another, but so weakly that they can move past each other. Liquids can change shape.
What are the particles like in gases?
In gases, the particles are not attached to each other and can move anywhere by themselves. Gases can also change shape.
Explain the properties of a solid.
Things can only change their volume if the particles in them spread out or get closer together. In a solid, the particles are already very close together. This makes it very difficult for the volume of a solid to be smaller.
Solids have a fixed shape because the particles are held tightly together by special forces called bonds. These bonds are very strong, and they stop the particles from moving around. The particles are fixed in place and can only vibrate. This stops the whole solid from flowing.
Explain the properties of a liquid.
The volume of a liquid cannot be changed. Liquids cannot be squashed because the particles in a liquid are already close together.
The particles in a liquid are close together but they can move past each other quiet easily. The bonds in a liquid are weak enough to let the particles move about but strong enough to hold them close together.
Explain the properties of a gas.
Particles in a gas are very far apart and move very quickly in all directions. The particles are able to move all over the place because there are no bonds between them. Therefore, a gas does not have a fixed volume or shape.
When we squash a gas, the particles are moved close together. The more the gas is squashed, the closer the particles will get.
Expanding solids/liquids.
When a solid or a liquid is heated, the particles begin to move further apart, making the material bigger. This is called expansion. Although the material gets bigger, there are still the same amount of particles in it, but they are more spread out.
What is contraction?
When a material is cooled, the particles move more slowly and get closer together. This is known as contraction.
Why is the expansion of solids a problem?
The expansion of solids can cause a problem for designers. When a new road bridge is built, special expansion strips are added so that the bridge can expand in the summer heat without buckling and contract in the winter without leaving a gap.
Do liquids expand?
Liquids also expand when they are heated. We can use this property of liquids to measure temperature changes. A thermometer is filled with a liquid which expands when it gets warmer and contracts when it gets cooler.
Why is water different (expanding and contracting)
Most liquids contract when they get colder. Water is different and expands when it cools below 4 degrees. This is why glass bottles which are full of water should never be put in a freezer.
More about solids……
Solids tend to stay in one place unless they are pushed or pulled. Once a solid object has been loaded onto a lorry, it stays there because a solid doesn’t flow.
We say that any object that is heavy for its volume is dense. Solids are often dense.
More about liquids……
It would be very difficult to transport water into the aquarium. The aquarium would be very heavy and the water would slosh about as it was moved. This shows us one of the important properties of liquids - they flow.
Some liquids flow more easily than others eg. water flows more easily than treacle.
Liquids cannot be squashed. Liquids are quite dense, but they are usually less dense than solids.
All liquids can be pumped into and out of tankers because liquids can change shape. This means that a tanker can be filled and sent to the place where the liquid is needed, without spilling a drop.
More about gases……
In one day, a normal person breathes the volume of air contained in a small room. We can only get all this air into a small room if we squash it.
Air is a mixture of gases and all gases can be squashed.
When we squash a gas, we make its volume smaller. Gases do not have a fixed volume - they fill the whole of the space they are in. When we put the gas into the room, we change its shape and volume.
