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COOLINVENTOR

PHYSICS PROJECT

SUBMITTED BY: NUSRAT JARIN SILVIA

PROJECT TITLE: CURIOUS NANCY AND THE DANCY OF FIVE ICE CUBES

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THE CORE OF THE PROJECT

The science teacher began the experiment, taking 5 cubes of ice at -4 degrees centigrade onto a beaker, crushing it and then placed a thermometer in it. He heated the beaker for a good 5 minutes until the temperature reached 120 degrees centigrade. Nancy noticed that there were two instances where the temperature remained constant for some time.

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BY NOW, THE CURIOUS MIND OF NANCY HAD TWO QUESTIONS IN MIND.

Why were the ice cubes crushed?

�2. What was happening during the two instances where the temperature was not increasing for some time?

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Ans: The science teacher crushed the ice before heating instead of using the ice cubes directly to enhance the thermal contact between the ice and the beaker. Crushed ice has more surface area than ice cubes. The area of contact became more when the ice is crushed. With decreasing size of ice the surface area got increased. It saved the energy and time both melting the ice and boiling the water. Look at the picture beside. You will get a better understanding of it.

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2. Ans: There were two instances where the temperature was not increasing for some time. The two instances were:

Melting point of the ice
Boiling point of the water

If the temperature reaches a definite value, the solid starts to melt. This process is called Fusion and the temperature at which the fusion starts is called the melting point.

Ice is a solid matter. When heat was applied to those ice its temperature went up. When measuring the temperature they noticed that when fusion has started, the temperature of the thermometer did not increase any more but the heat was still being applied.

Why? The answer is during this time the heat was used to loosen the intermolecular bonds of the molecules in the ice. So, the temperature could not rise because applied heat could not make the molecules move further.

During fusion at a definite melting point the amount of heat which is used to convert the whole solid into liquid, is called the Latent Heat of Fusion.

Instance 1:

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Instance 2:

The temperature increased gradually and at one stage the water started to convert into vapor. This process is called vaporization and the temperature at which vaporization occurs is called the boiling point.

When the process of vaporization started by absorbing the heat energy, the molecules of water started to become free from the molecular bonds among themselves. Here also the temperature did not increased like fusion even heat was applied.

During vaporization of liquid the amount of heat by which the whole liquid is converted into a gas, that heat is called Latent Heat of Vaporization.