Due to thermal expansion, with rise in temperature
a) Metallic scale reading becomes lesser than true value
b) Pendulum clock goes fast
c) A floating body sinks a little more
d) The weight of a body in a liquid increases

Due to heating:

1. Metallic scales expand. Distance between its marks increases. Hence measured length of a body decreases.

2. Pendulum clocks: $\mathrm{T}=2\mathrm{\pi }\sqrt{\frac{\mathrm{l}}{\mathrm{g}}}$. Length of pendulum increases, increasing the time period. So oscillations happen less frequently. In a given time, it makes less ticks, counts less time. Clock goes slow.

3. Solid body floating in a liquid: Both the solid body and the liquid in which the solid body is floating undergo expansion. Liquid's density decreases due to heating. 

Weight = upthrust = $V_{in}{\rho }_{l}g$. To balance the weight of the body, solid displaces more volume of liquid (it sinks more).

4. If a solid is fully immersed in a liquid, upthrust given by $V_s{\rho }_{l}g$ decreases (as ${\rho }_l$ decreases. So, apparent weight increases.

Apparent weight = true weight minus upthrust.