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jaejoon89
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My baseline for the DSC goes past zero (below 0 W/g) why would the instrument be doing this?
A DSC (differential scanning calorimeter) measures the heat flow of a sample as it undergoes temperature changes. When the sample absorbs heat, the DSC reading goes up, and when it releases heat, the reading goes down. Therefore, if the sample is losing heat faster than it is absorbing it, the DSC reading can go below zero.
Yes, it is normal for a DSC to go below zero. In fact, it is a common occurrence and is often seen in experiments involving phase transitions, where the sample is undergoing a change in state from solid to liquid or vice versa.
No, a DSC cannot go below zero if there is no sample present. The DSC measures the difference in heat flow between a sample and a reference material, so without a sample, there is no heat flow to measure.
Aside from phase transitions, other factors that can cause a DSC to go below zero include measurement errors, incorrect calibration, or a malfunctioning instrument. It is important to carefully follow the manufacturer's instructions and properly calibrate the DSC before conducting experiments.
Interpreting a DSC reading that goes below zero depends on the specific experiment and sample being analyzed. If the sample is undergoing a phase transition, the DSC can provide valuable information about the enthalpy of the transition. However, if the DSC reading goes below zero unexpectedly, it may indicate a measurement error or an issue with the instrument that should be investigated.