Final answer:
Touching a beaker during an endothermic reaction would make it feel colder since heat is absorbed from the surroundings by the system.
Step-by-step explanation:
During an endothermic reaction, heat is absorbed from the surroundings into the system. As a result, the surroundings, including a beaker in which the reaction is taking place, get cooler.
Therefore, if we touched the beaker during an endothermic reaction, it would feel colder to us because heat is being absorbed from the surroundings into the system making it cooler.