trouble with temperature changing quickly inside test tubes
Posted: Sun Dec 02, 2012 10:59 pm
Today we tried the solution of 5.8 g NaCl + 100 g H20. The thermometer in the test tube read -9 Degrees Celsius before the solution started to freeze. Then the solution in the tube would freeze up with ice crystals forming quite rapidly. While the ice crystals formed the temperature rose to the more predicted level of around -4 Degrees Celsius. So we are not certain whether to record -9 C or -4 C as the freezing point of the solution. Is there something we are doing incorrectly? We are stirring the solution with the thermometer and we were very careful to measure the water and the salt. Thank you for your help!