Lipids to fat: Chemical, since ingestion is in process to make this change possible.
Hat: Gravitational, since gravity causes objects to pull toward each other, here it is the Earth and the hat.
Wave of water: Mechanical, since the movement of energy is visible and clearly touchable.
Burner to kettle: Thermal, since heat is involved.
Power plant: Nuclear, since splitting atoms is part of the process called nuclear fission.
Nerve: Electrical, since nerves function by sending electrical pulses.
Sun to plant: Radiant, since the sun's electromagnetic waves/radiation are being transferred.
