Thermal Energy Transfer and Its Effects

Flashcards about thermal energy transfer, expansion, contraction, and their applications.

What happens to solids, liquids, and gases when thermal energy is absorbed?

Generally, they expand.

What happens to solids, liquids, and gases when thermal energy is given out?

Generally, they contract.

What does thermal expansion result in?

An increase in volume of the substance and therefore the density of the substance.

When matter is heated, what generally happens to its volume?

It increases.

What is the increase in volume when matter is heated called?

Expansion.

According to the Kinetic Particle Theory, what happens when matter is heated?

It gains thermal energy, particles gain kinetic energy and move further apart, volume increases, and expansion occurs, generally decreasing in density if mass remains constant.

When matter is cooled, what generally happens to its volume?

It decreases.

What is the decrease in volume when matter is cooled called?

Contraction.

According to the Kinetic Particle Theory, what happens when matter is cooled?

It loses thermal energy, particles lose kinetic energy and move closer together, volume decreases, and contraction occurs, generally increasing in density if mass remains constant.

For the same rise in temperature, which expands the most: solids, liquids, or gases?

Gases expand the most, followed by liquids, then solids.

Why do gases expand more than solids or liquids for the same rise in temperature?

The forces of attraction between particles in gases are the weakest, allowing them to easily overcome these weak forces and move a greater distance apart when heated.

Why do MRT tracks and concrete pavements have gaps in between them?

To allow for expansion in hot weather, preventing bending, buckling, or cracking.

Why are overhead wires not stretched tightly when they are installed?

To prevent them from breaking in cold weather when they contract and tighten.

Why do engineers design expansion loops in metal pipes?

To provide a controlled and flexible area where the pipe can expand or contract, mitigating issues like distortion, buckling, leaks, or structural damage.

What is a rivet used for?

Holding metal plates together firmly, especially in constructions where water leakages must be prevented (e.g., ships).

Describe the process of using a rivet.

A heated rivet is passed through holes in metal plates, hammered to fix it firmly, and upon cooling, it contracts to hold the plates together more firmly.

What is a bimetallic strip made of?

Two metals that expand at different rates upon the same change in temperature.

How does a bimetallic strip work?

When heated, the metal with a higher expansion rate expands more, causing the strip to bend.

Give an example of how bimetallic strips are used.

As a temperature-sensitive switch in electrical circuits, such as in thermostats in electric irons, refrigerators, and ovens, to keep the temperature of an appliance constant.