With the help of an activity, show the thermal expansion of liquids.
Answers
Explanation:
Most liquids follow a fairly predictable pattern of gradual volume increase, as a response to an increase in temperature, and volume decrease, in response to a decrease in temperature. Indeed, the coefficient of volume expansion for a liquid generally tends to be higher than for a solid, and—with one notable exception discussed below—a liquid will contract when frozen.
The behavior of gasoline pumped on a hot day provides an example of liquid thermal expansion in response to an increase in temperature. When it comes from its underground tank at the gas station, the gasoline is relatively cool, but it will warm when sitting in the tank of an already warm car. If the car's tank is filled and the vehicle left to sit in the sun—in other words, if the car is not driven after the tank is filled—the gasoline might very well expand in volume faster than the fuel tank, overflowing onto the pavement
Take a round bottomed flask and fill it with coloured water up to the brim.
Close the flask with a single-holed rubber stopper.
Insert a capillary tube into the flask such that some water from the flask gets into the capillary tube and reaches a certain level.
Heat the flask over a burner.
Observe the level of water in the capillary tube.
As the flask is heated, the water expands, and the level of water in the capillary tube rises.
This is due to the thermal expansion of water.
Now stop heating the flask and observe the level of water in the capillary tube. The level of water goes down as the temperature of the water in the flask decreases. Liquids expand on heating, and contract on cooling. Thus, liquids expand on heating and contract on cooling.