This specific process (the freeze-thaw cycle) is called frost weathering or cryofracturing. Temperature changes can also contribute to mechanical weathering in a process called thermal stress. Changes in temperature cause rock to expand (with heat) and contract (with cold).

The process is sometimes assisted by water. There are two main types of physical weathering: Freeze-thaw occurs when water continually seeps into cracks, freezes and expands, eventually breaking the rock apart.

Thermal expansion and contraction affect the volume and pressure of tires, volleyballs, and basketballs. When cars are moving quickly, the rubbing between the tires and the road increases the temperature of the air in the tires. This causes the tires to expand.

Thermal expansion examples

• Cracks in the road when the road expands on heating.
• Sags in electrical power lines.
• Windows of metal-framed need rubber spacers to avoid thermal expansion.
• Expansion joints (like joint of two railway tracks).
• The length of the metal bar getting longer on heating.

The expansion of alcohol in a thermometer is one of many commonly encountered examples of thermal expansion, the change in size or volume of a given mass with temperature. Railroad tracks and bridges, for example, have expansion joints to allow them to freely expand and contract with temperature changes.

There are three types of thermal expansion depending on the dimension that undergo change and that are linear expansion, areal expansion and volumetric volume.

Thermal expansion is the tendency of matter to change in shape, area, and volume in response to a change in temperature. All three states of matter (solid, liquid and gas) expand when heated. When a solid is heated, its atoms vibrate faster about their fixed points.

Thermal Expansion – Real-life applications

• ENGINE COOLANT. Another example of thermal expansion on the part of a liquid can be found inside the car’s radiator.
• WATER.
• THE GAS LAWS.
• VOLUME GAS THERMOMETERS.
• JAR LIDS AND POWER LINES.
• EXPANSION JOINTS.
• MERCURY IN THERMOMETERS.
• THE BIMETALLIC STRIP IN THERMOSTATS.

Thermal expansion is caused when seawater expands because of the higher temperature of the water. Since the oceans absorb heat from the atmosphere, when the atmosphere becomes warmer so will the oceans. Warm seawater has a greater volume than cold seawater.

The solids with the highest coefficients of thermal expansion are the ones that have weak inter-molecular bonds, typically polymers, which also tend to have low melting points.

Substances expand (increase in size) when they get warmer, and they contract (decrease in size) when they get cooler. This property can be useful. For example: Thermometers work because the liquid inside them expands and rises up the tube when it gets hotter.

The thermal expansion of solids is a basic physical property representing the dimensional changes in a solid induced by a change in temperature. It is of technical importance as it determines the thermal stability of a crystal. The thermal shock resistance of crystals depends on the thermal expansion (Campbell, 1962).

Advantages of a Thermal Expansion Valve

• Adaptable Refrigerant Flow.
• Keeps the Evaporator Active and in Optimal Performance.
• Higher Power Efficiency.
• Eliminates Risk of Compressor Breakdown.
• Handles Variation in Refrigerant Charge.
• Better Temperature Control.

Effect on density Thermal expansion changes the space between particles of a substance, which changes the volume of the substance while negligibly changing its mass (the negligible amount comes from energy-mass equivalence), thus changing its density, which has an effect on any buoyant forces acting on it.

Perhaps the most important exception to this rule is water. Water contracts as it cools from its boiling point to about 39.2°F (4°C). At that point, it begins to expand as it cools further to its freezing point. This unusual effect explains the fact that ice is less dense than water.

In almost all substances the atoms and molecules move closer together as they get colder. They then solidify. Water, however, attains its greatest density at four degrees Celsius because the water molecules are packed closest together at this temperature.

Water does indeed expand when warms, and it contracts when it cools, but not at all temperatures. An oddity occurs between 4 and 0 degrees Celsius (about 40 and 32 degrees Fahrenheit). As water cools from 4 to 0 degrees Celsius, it expands because it’s crystallizing into ice.

Solid water, or ice, is less dense than liquid water. Ice is less dense than water because the orientation of hydrogen bonds causes molecules to push farther apart, which lowers the density.

In general, when considering the states of matter, solids are more dense than liquids and liquids are more dense than gases. Water is a bit of a contrarian in this regard. When water is in its solid state (ice), the water molecules are packed close together preventing it from changing shape.

Density is the mass of a material per unit volume. Adding salt to the water increases the density of the solution because the salt increases the mass without changing the volume very much. When enough salt is added to the water, the saltwater solution’s density becomes higher than the egg’s, so the egg will then float!

Adding salt to water makes the water denser. As the salt dissolves in the water, it adds mass (more weight to the water). This makes the water denser and allows more objects to float on the surface that would sink in fresh water. About 3.5 percent of the weight of seawater comes from the dissolved salts.

Here’s why: Salt is about 25% more dense than sugar. Therefore a teaspoon of salt weighs more than a teaspoon of sugar by almost 25%. Your dissolving test would not be accurate because you would be starting out with a larger mass of salt than sugar.

The density of water can also be affected by temperature. When the same amount of water is heated or cooled, its density changes. When the water is heated, it expands, increasing in volume. The warmer the water, the more space it takes up, and the lower its density.