Putting something cold into a preheated oven and then turning it on generally won't cause any significant damage to the oven itself. Ovens are designed to withstand high temperatures, and the sudden introduction of a cold item shouldn't cause immediate harm. However, there are a few factors to consider:
Thermal Shock: If the temperature difference between the cold item and the oven is extreme, it could potentially lead to thermal shock. Rapid and severe temperature changes can cause materials, such as glass or ceramic, to crack or shatter. This is more likely to happen with delicate items or cookware not designed for high temperatures.
Uneven Heating: Placing a cold item in a preheated oven might temporarily affect the temperature distribution inside the oven. The oven may take longer to reach the desired temperature, and the cold item could slightly cool down the surrounding air. However, modern ovens are generally equipped with heating elements that compensate for temperature fluctuations and adjust accordingly.
It's worth noting that if the cold item has a lot of moisture or is covered in a liquid, it may cause some sizzling or steam as it heats up, which is normal. Additionally, the overall cooking time may be slightly extended due to the initial temperature difference.
To minimize any potential risks, it's generally recommended to allow food or cookware to come closer to room temperature before placing them in a preheated oven. This helps to avoid extreme temperature differentials and reduces the chances of thermal shock.