Physical Science- Chapter 8 Review “Solids, Liquids, and Gases” Mrs. Nell

States of Matter There are four states of matter: 1)Solid 2)Liquid 3)Gas 4)Plasma The state of matter depends on its temperature.

Characteristics of Solids Every solid has a definite shape and a definite volume. In other words- solids keep there shape and since a solid can’t be squeezed into a smaller space- we say it has a definite volume.

The Kinetic Theory of Matter Tiny particles in constant motion make up all matter. The particles in solids are held close together. This is why a solid can’t be squeezed into a smaller space and why it holds its shape.

Crystalline Solids In most solids, the particles are arranged in repeating geometric patterns called crystals.

Other Crystalline Solids A snowflake is a crystal of water that has the shape of a hexagon.

Noncrystalline Solids Some materials- like glass, plastics, and some kinds of wax- appear to be solids but are not made of crystals. These materials are called noncrystalline solids or amorphous solids.

Characteristics of Liquids Liquids do not have a definite shape. Liquids flow and take the shape of the container it is in. Liquids do have a definite volume. They can’t normally be squeezed to a smaller volume.

Motion of Particles in Liquids Liquids can’t be squeezed because their particles are close together like solids, but the particles are able to move over and around each other. This allows the liquid to flow and take the shape of its container. Liquid particles can’t be forced to fit in a smaller container or expand to fill a larger container.

Characteristics of Gases Gases can expand and take the shape of their container. They do not have a definite volume and they do not have a definite shape.

Movement of Gas Particles Gas particles have enough energy to separate completely from one another. They can expand or be squeezed into a smaller space.

Characteristics of Plasma Plasma is a gaslike mixture of positively and negatively charged particles. The particles become charged as they are heated to high temperatures and slam into other particles. As these particles collide they break apart and become electrically charged. The most common state of matter in the universe is plasma- it makes up the stars.

Thermal Expansion Almost all matter expands as it gets hotter and contracts when it cools. This is called thermal expansion. Expansion joints allow buildings and bridges to expand in hot weather and shrink in cold weather without cracking the concrete.

Water Pollution Polluted water refers to water that contains high levels of unwanted materials and is unacceptable for drinking. Water is polluted by animal and plant wastes, fertilizers, pesticides, and herbicides. Thermal pollution can also occur. Thermal pollution occurs when industries release heated water into rivers. When the temperature of the water rises it kills some of the organisms that live in the rivers.

Changes in State Melting is when matter changes from a solid into a liquid state. Freezing is when matter changes from a liquid into a solid state.

Vaporization & Evaporation Vaporization is when a liquid changes to a gas when boiled. Evaporation is when a liquid changes to a gas gradually at temperatures below the boiling point.

Sublimation & Condensation In Sublimation a solid changes directly to a gas without going through the liquid state. Sublimation causes ice cubes to shrink and foods to become freezer-burned after sitting in the freezer for a long time. The most common example of sublimation is dry ice (frozen CO 2 ). When dry ice is exposed to the air it begins to sublimate, or change to vapor. This happens because dry ice would rather be a gas than frozen solid at room temperature.

Heat of Fusion The amount of energy needed to change a material from the solid state to the liquid state is the heat of fusion. For water, the heat of fusion is 334 kJ/kg.

Heat of Vaporization The amount of energy needed to change a material from a liquid to a gas is the heat of vaporization. For water the heat of vaporization is 2260 kJ/kg.

Pressure The total amount of force exerted by a gas depends on the size of its container. Pressure is the amount of force exerted per unit of area. Pressure is measured in pascals or kilopascals. In our atmosphere the higher you go the less pressure there will be. P = F A

Boyle’s Law Boyle’s Law states that if you decrease the volume of a gas, the pressure of the gas will increase and if you increase the volume of a gas, the pressure will decrease. (provided the temperature does not change). V P

Boyle- Under Pressure Robert Boyle ( )

Charles’s Law Charles’s Law states that the volume of a gas increases with increasing temperature and the volume of a gas decreases with decreasing temperature (provided the pressure does not change). V T

Charles- The Hydrogen Balloon Jacques Charles ( )

Absolute Zero Charles believed that all particle motion of matter would stop and that a gas would have a volume of zero at -273 degrees Celsius (absolute zero). In reality, the particles will not come to a complete stop. Gases cannot be cooled to zero volume- they condense to liquids when cooled below their boiling points.

Archimedes’ Principle Archimedes’ principle states that the buoyant force on an object in a fluid is equal to the weight of the fluid displaced by the object. A steel boat will float if the boat displaces enough water to equal its weight.

Archimedes- Why Boats Float Archimedes of Syracuse ( BC)

Pascal’s Principle Pascal’s Principle states that pressure applied to a fluid is transmitted unchanged throughout the fluid. If you squeeze one end of a balloon, the balloon will pop out on the other end. If you squeeze one end of a toothpaste tube, the toothpaste will come out the other end. A common application of this is a hydraulic lift used to raise a car off the ground so it can be repaired at a garage. Applied pressure on a small piston is transferred to a large piston. If a car sits on top of the large piston, it can be lifted by applying a relatively small force to the smaller piston.

Pascal- Hydraulics Blaise Pascal ( )

Bernoulli’s Principle Bernoulli’s Principle states that as the velocity of a fluid increases, the pressure exerted by the fluid decreases. Air is a fluid. An airplane’s wing is shaped so that air flows at a greater velocity over its upper surface. The difference in pressure above and below the wing creates a net upward force that helps lift the plane.

Bernoulli- Why Planes Fly Daniel Bernoulli

The Venturi Effect Fluids flow faster when forced to flow through narrow spaces. When the speed increases, the pressure of the fluid drops. This reduction in pressure in these spaces is a special case of Bernoulli’s Principle called the Venturi effect.

The Venturi Effect in Baseball When a baseball spins air moves faster along the side of the ball that is spinning away from the direction of the throw. In the 60 foot 6 inch distance between major league pitcher and batter, this curving force can move a ball down a foot or more. *Backspin of a baseball in a water tunnel