Solution: (i) Density (ii) thermal
Liquids at lower temperatures have greater density when compared to liquids at higher temperatures.This is because, at higher temperatures, molecules have greater kinetic energy and hence they are spaced farther apart, when compared to molecules at lower temperatures. Thus, the colder layers of liquids are heavier than the warmer layers, which causes then to move down due to gravity. For the same reason, the hotter layers move upwards through the liquid.
When a liquid is heated, the molecules closest to the heat source have greater energy, their density becomes less and they move upwards. The colder layers sink downwards. The layers of the liquid which were cold initially, get heated and they travel upwards. As the process repeats, convection currents are set up in the liquid.
These currents transfer the thermal energy derived from the source throughout the liquid. The process stops when the entire liquid is at the same temperature.
Thus, convection currents occur in liquids due to temperature and <u>density</u> differences. Convection currents transfer <u>thermal</u> energy throughout a fluid.
Answer:
Centre of mass is the point at which the distribution of mass is equal in all directions, and does not depend on gravitational field. Centre of gravity is the point at which the distribution of weight is equal in all directions, and does depend on gravitational field.
Explanation:
google
Answer:
Either energy transformation or energy conversion
Depends on which one you were taught.
Answer:
I'm pretty sure it's mist, drizzle, droplet, and then rain.
An open system can exchange both matter and energy with the surroundings. Δ H is measured when
an open system is used as a calorimeter.
A closed system has a fixed amount of matter, but it can exchange energy with the surroundings. Δ U is
measured when a closed system is used as a calorimeter because there is no change in volume and thus no
expansion work can be done.
An isolated system has no contact with its surroundings. The universe is considered an isolated system but on
a less profound scale, your thermos for keeping liquids hot approximates an isolated system.