Explain thermal expansion process with the help of diagram and two suitable examples
from daily life
Answers
Explanation:
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.
Thermal expansion examples
Here Are Some Examples of thermal expansion in our Daily Life.
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.
Tire bursts in hot days when filled full of air due to thermal expansion.Examples of Thermal Expansion
Okay, so let's go through a few examples of thermal expansion. I said at the start of the lesson that bridges would collapse if we didn't understand thermal expansion, and that's true. Bridges have a feature called an expansion joint, containing little jagged teeth with a cap in-between. If the bridge material expands and the bridge gets longer, the teeth move closer together, and if it contracts, they move further apart. This allows the bridge to change in length without it, you know . . . collapsing in a chaotic mess of broken metal and falling cars.
Another example? Opening a tight jar; when you can't open a jar, what do you do? Well, there are a lot of tricks. Maybe you tap the lid of the jar against the counter to break the seal. Maybe you use one of those grippy rubbery things - that's a technical term. But one way you can open a tight jar is by running the lid under a hot tap. This causes the lid to expand. But wouldn't an expanding lid make it tighter?
To explain this, imagine heating up a doughnut-shaped piece of metal. Mm . . . doughnuts. Does the doughnut hole get larger or smaller? People sometimes think smaller, because they imagine the expanding doughnut filling the hole, but if the complete shape expands, the hole also gets larger. So if you heat up a jar lid, the gaps between the lid and the glass threads get larger, making it easier to open.
A thermometer also works by expansion. The liquid in a thermometer - which used to be mercury, but is now usually an alcohol of some kind - expands as it gets hotter, and the marks on the glass are calibrated to tell you the temperature based on how much the liquid's expanded.
Okay, one more example: the gas gauge on a car. People are much more likely to run out of gas in the summer than the winter. Why is that? Well, the gas in your car expands, like anything else, and changes the reading on your fuel gauge. In the summer, the gas takes up more space in the tank, and so when it reads empty, there's significantly less fuel left in the tank than in winter. Maybe you get an extra 35 miles after it hits empty in the winter, but that won't be the case in the heat of summer. So, be careful out there! Don't be the fool who has to walk three miles to the gas station because they don't know about thermal expansion.