(a)[2]
Explain, in terms of density, why bulb A is at the bottom of the cylinder while the other bulbs are floating.
(b)[4]
(i) Suggest one reason for the delay before the water temperature rises to $23^{\circ}\text{C}$. (ii) Explain why, after this delay, bulb B sinks. Assume the bulbs do not expand.
(c)[1]
State the temperature range that could apply to the water in the cylinder.