To measure what occurs to metal in a microwave without relying on the visual effect, you can use non-destructive testing methods to observe changes in the metal's physical properties caused by the microwave radiation. Here are a few potential methods:
Temperature measurement: Use temperature sensors like thermocouples or infrared thermometers to monitor the metal's temperature during microwave exposure. Metal objects can heat rapidly in a microwave due to the induction of electric currents, and this temperature increase can be measured and recorded.
Eddy current testing: Eddy current testing is a non-destructive testing technique used to detect surface or subsurface defects in conductive materials. You can pass a low-frequency alternating current through the metal and measure the response to assess changes in its electrical conductivity.
Magnetic measurements: Microwaves can induce magnetic fields in certain metals, particularly those that are ferromagnetic or paramagnetic. You can use a magnetometer or Hall effect sensor to measure any magnetic field changes induced by the microwave radiation.
Dielectric properties measurement: Metals have a significant impact on the dielectric properties of the surrounding materials when exposed to microwaves. You can use a vector network analyzer or other suitable equipment to measure how the presence of the metal affects the electromagnetic fields in the microwave oven.
Spectroscopy: Analyze the metal using various spectroscopic techniques like X-ray spectroscopy or energy-dispersive X-ray spectroscopy (EDS) to detect any elemental changes or redistribution due to microwave exposure.
Resonance testing: Certain metals can exhibit resonance effects when exposed to microwave radiation. You can use specialized equipment to identify and analyze these resonance frequencies.
Keep in mind that experimenting with metal in a microwave can be potentially hazardous and should only be conducted with proper safety precautions and the right equipment. Also, it's crucial to consult with experts in non-destructive testing to ensure the proper use of these techniques for your specific application.