Final answer:
The leakage of water from a starch gel is likely due to the gel being too hot, causing syneresis as it cools and contracts. This phenomenon is analogous to the thermal stress seen when cold water comes into contact with hot glass, which Pyrex® with its small coefficient of linear expansion resists better.
Step-by-step explanation:
The cause of water leaking from a starch gel, often referred to as syneresis, is likely due to the gel being too hot. When a gel is heated, the molecular chains within it can become more fluid, which can lead to water being expelled from the network. This is similar to how pouring cold water into hot glass can break it due to thermal stress. The temporarily increased fluidity of the gel network can cause water to be squeezed out as the gel contracts during cooling. In the case of Pyrex®, the material is less susceptible to breaking from thermal stress because it has a small coefficient of linear expansion, meaning it expands and contracts less with temperature changes compared to regular glass.