Hero photograph
 
Photo by Jess Lang

Ice Ice Baby

Jess Lang —

For our Chemistry unit we have been looking at changing states. Today we made ice cream to look at the chemical reaction and changes of state between liquid and solid

By mixing ice and salt, we made ice cream! 

Water has three states: solid, liquid and gas. Water changes into its solid state when it reaches 0 degrees Celsius, but if there is Sodium Chloride (NaCl) present, otherwise known as salt, then that temperature drops. That’s because salt lowers water’s freezing point. Have you ever noticed how when the sidewalk is icy they put salt on it to melt the ice and make it safer for walking? That’s the same principle. The salt they put on the sidewalk mixes with the ice and because it's freezing point is lower than the temperature of the unsalted ice, the sidewalk melts.