How Entropy Powers The Earth (Big Picture Ep. 4/5)

The video explains Earth's energy balance, highlighting that while the Earth receives and radiates energy, the key is the form of energy. Useful energy is low entropy and can perform work, while useless energy is high entropy and cannot. Examples like water behind a dam and gasoline illustrate energy conversion. The Sun provides low entropy energy, which Earth eventually radiates as high entropy infrared photons. The concept of entropy and energy equilibrium is crucial, as it determines the usability of energy.

What is the significance of low entropy energy in the context of Earth's energy balance?

• It is the form of energy that is always conserved.

• It is the form of energy that can be used to perform work.

• It is the form of energy that is always lost as heat.

• It is the only form of energy that can be stored.

Which of the following is an example of energy in a low entropy form?

• Noise from a running engine.

• Gasoline and air mixture before combustion.

• Potential energy of a stationary ball.

• Heat from a cooling cup of tea.

How does the transformation of energy affect its usefulness?

• Energy usefulness is not affected by its entropy state.

• Energy becomes less useful as it transforms to a higher entropy state.

• Energy remains equally useful regardless of transformation.

• Energy becomes more useful as it transforms.

Why is the Sun considered a source of useful energy?

• Because it is a hot spot in a cold sky, providing low entropy energy.

• Because it is the only source of energy for Earth.

• Because it provides energy in a high entropy form.

• Because it is a constant source of energy.

What would happen if the entire sky were at the Sun's temperature?

• The Earth would receive less energy.

• The Earth would reach a high entropy equilibrium, making energy useless.

• The Earth would become a source of low entropy energy.

• The Earth would stop radiating energy into space.