Final answer:
When welding two dissimilar materials, the preheat temperature can be determined by considering the expansion properties of each material. An example of determining preheat temperature can be seen in a situation where a steel rod and an aluminum rod are welded end to end. Specific heat can also be determined using similar experimental methods.
Step-by-step explanation:
When welding two dissimilar materials, the preheat temperature can be determined by considering the expansion properties of each material. The preheat temperature should be high enough to ensure proper fusion of the materials during welding, but not so high that it causes distortion or other issues.
An example of determining preheat temperature can be seen in a situation where a steel rod and an aluminum rod are welded end to end. One end of the steel rod is placed in boiling water while the far end of the aluminum rod is placed in water at a lower temperature. The temperature at the joint can be calculated using the principles of heat conduction.
It's important to note that specific heat, which is a property related to heat capacity, can also be determined using similar experimental methods. By conducting experiments and measuring temperature changes, the specific heat of the materials can be calculated.