Cold can flow. Gases can be compressed to zero volume. Heat and temperature are the same thing. Heat and cold flow like liquids. Pressure is the same as force.
Skin is a good thermometer.
The period of oscillation depends on the amplitude. The restoring force is constant at all points in the oscillation. The heavier a pendulum bob, the shorter its period. All pendulum motion is perfect simple harmonic motion, for any initial angle. Harmonic oscillators go forever.