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### Course: Biology archive>Unit 5

Lesson 2: Laws of thermodynamics

# Introduction to energy

Energy is defined as the ability to do work. Energy can be found in many things and can take different forms. For example, kinetic energy is the energy of motion, and potential energy is energy due to an object's position or structure. Energy is never lost, but it can be converted from one form to another.

## Want to join the conversation?

• Why the positive charge is accumulated at the top of cloud why not at bottom?
• The positive charge is less dense than the electrically charged particle. Hence the proton goes to the top, where as the electron sinks to the bottom. You can think of it as convection except with particles rather than gas or liquids.
• What is 'energy' fundamentally though? From watching the video, is it loose electrons? Or the movement of electrons across atoms?
• I'm not a physicist, but I think "potential to do work" is the accepted definition.

I'm pretty sure it isn't specific to electrons — for example gravitational potential energy doesn't seem to require electrons.
• Is radiant energy the same as light energy?
• Light energy is a form of radiant energy. Radiant energy refers to the entire spectrum of electromagnetic waves while light energy refers to the Visible Light of the spectrum.
• Where does Joules play a role in energy? Like where did that come from?
• The Joule is the SI-Unit for Energy its defined as 1 kg m^2 / s^2 or 1 Nm. Its called Joule after the scientist James Prescott Joule. For example 1 Joule is the energy to lift an object weighing 0,102 Kg 1m. Or to warm 1 g of water 1K.
• So thermal energy is from fire,
need more explanation.
• because it creates heat and thermal is like saying heat.
• AT , Why do electrons come to ground,and not to higher levels of clouds?
• Because they are attracted to the positive nucleus, and we define the closest they can get to the nucleus as the ground state.
• "Fires are, definitely hot". - Lifechanging.
• When he explained the last example about the man flipping off a cliff, shouldn't it both be potential energy before and after he lands? And kinetic in-between?
• If he just lands in the water (without the pulley), his kinetic energy would get converted to heat and sound.
With the pulley in place, his kinetic energy would be used to increase the gravitational potential energy of the weight.