Water changing state 1 Mar 2013

In Tamar today we learned about water changing state. We learned that pure water freezes at 0 degrees C and boils at 100 degrees C. Mr Wild demonstrated the temperature line graph that is made when iced water is boiled, using the data logger. We watched the graph being created in real time while watching the water boil and evaporate using the visualiser.

This is what the graph shows us:
At A the data logger shows room temperature until the sensor is plunged into iced water. At B the temperature reaches its lowest point, about 1 degrees C until it is heated. The temperature rises steadily until C, when it reaches 100 degrees C. The water remains at 100 degrees C until salt is added at D. Salt is added in stages until the salt solution becomes saturated and reaches a maximum boiling temperature of 110 degrees C. At E, the sensor is removed from the pan and the temperature shown on the data logger drops rapidly, in a steep cooling curve until it once again reaches room temperature at around 19 degrees C.

What a lot of excellent science and ICT! The pictures below have been annotated using Skitch on the iPad.