Let's find the melting point of a sample of Benzoic Acid. Step 1: Fill a thin capillary tube with a small amount of powdered benzoic acid (about 2-3 mm high). Step 2: Attach the tube to a thermometer using a small rubber band, ensuring the acid is right next to the thermometer bulb. Step 3: Lower the thermometer into an oil bath. Step 4: Heat the oil slowly. Step 5: Keep your eyes on the acid. When you see the first drop of liquid appear, check the thermometer. Let’s say it reads 121°C. This is the start of the melting range. Step 6: Continue heating until the entire powder has become clear liquid. Let’s say the thermometer reads 123°C. This is the end. Conclusion: The melting point range is 121°C to 123°C. Because this range is very small (only 2 degrees), we know our benzoic acid is very pure.