When an object is cooled, the energy of its molecules decreases. Cooling reduces the thermal energy of the molecules, causing them to move more slowly.
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Heat is a type of energy that can be converted into work. Count Rumford (Benjamin Thompson) first gave direct evidence of this through his experiments on the boring of cannons, which demonstrated the mechanical equivalent of heat.
The scientist who first melted two pieces of ice by rubbing them together was Sir Humphry Davy. He demonstrated that friction could generate heat, which melted the ice.
When some water is churned continuously, its temperature increases. In this process, mechanical energy is converted into thermal energy due to the work done on the water, which raises its temperature.
The temperature of boiling water in a steam engine can become high because there is high pressure inside the boiler. This elevated pressure increases the boiling point of water, allowing it to reach higher temperatures before vaporizing into steam.
The water in the hand pump is hot in winter because water comes out from inside and absorbs heat from the surroundings. As the water travels through pipes underground, it absorbs heat from the relatively warmer Earth. Consequently, when pumped ...
The hairs of the shaving brush stick together when taken out of water due to surface tension. Water molecules at the surface of the hairs attract each other, causing them to cling together. This phenomenon is a result of cohesive ...
When kerosene oil is added to stagnant water, mosquitoes reduce because it interferes with the breathing of the larvae. The thin layer of oil formed on the water’s surface blocks the larvae’s access to air, effectively suffocating them. This disrupts ...
The shape of a raindrop becomes spherical primarily due to surface tension. Surface tension causes water molecules at the surface to contract, pulling the raindrop into the shape with the least surface area, which is a sphere. This phenomenon occurs ...
The principle of purification by soap relies on surface tension. Soap molecules disrupt surface tension, allowing them to surround and lift away dirt and oil from surfaces. This process enables effective cleaning by ensuring that contaminants are dispersed and washed ...