Complete the crossword puzzle below by identifying the term being described by the clues given. 5 Across: 2. the Si unit of heat 4 gas state to liquid is called 6. from liquids to solids is called solidification or 8. substance that has a boiling point of 100 °C 3 13 10 lull le lo e 7 Down: 1. a device used to measure temperature 3. expands the greatest when heated at same temperature 5 temperature scale that William Thompson introduced 7 produced when molecules continuously vibrate 9. solid to liquid state is called Fusion or 6 8
The Correct Answer and Explanation is:
Crossword Answers:
Across
2. Joule – The SI unit of heat
4. Condensation – Gas turning into liquid
6. Freezing – Liquid turning into solid
8. Water – Boiling point of 100 °C
Down
- Thermometer – Device to measure temperature
- Gas – State of matter that expands most when heated
- Kelvin – Temperature scale introduced by William Thompson (Lord Kelvin)
- Heat – Produced by vibrating molecules
- Melting – Solid turning into liquid (also called Fusion)
Explanation
In thermodynamics and physical science, understanding heat and phase changes is essential. Heat, measured in joules, is the energy transferred due to temperature difference. It’s central to phase transitions, where substances change from one state of matter to another.
One such phase change is condensation, where gas becomes a liquid, typically when cooled. Conversely, freezing is the transformation of a liquid into a solid, often occurring when thermal energy is removed. These processes are crucial in both natural phenomena like rain formation and human applications like refrigeration.
Water is commonly studied due to its clear phase changes. It boils at 100 °C (at standard atmospheric pressure), making it a benchmark in many temperature-related studies.
To measure temperature, scientists use a thermometer, an instrument that may use mercury, alcohol, or digital sensors to indicate heat levels. Among various temperature scales, the Kelvin scale is most used in scientific contexts. Proposed by William Thompson, also known as Lord Kelvin, it starts at absolute zero, where all molecular motion theoretically ceases.
When substances are heated, gases expand the most among the three primary states of matter (solid, liquid, gas), due to their widely spaced molecules. This expansion is linked to the kinetic theory of matter, where increased energy causes more vigorous molecular motion.
Heat is the energy that results from vibrating molecules. All matter is made up of atoms that vibrate; more energy means more vibration, which we experience as higher temperature.
Finally, when a solid changes to a liquid, the process is called melting or fusion. It involves absorbing heat without a temperature increase, as energy is used to overcome molecular bonds rather than raise kinetic energy.
Understanding these basic principles is vital in science and daily life applications.
