Isaac's Science Experiment - Melting Ice Race

Last week, Isaac had to conduct a science experiment for school.  He decided to see what makes ice melt the fastest.  We got the basic idea for this experiment from here.

He started out by filling plastic cups with water.  Each cup had the same amount of water.

Then he put them in the freezer overnight.

The next day, we labeled a muffin tin with tape #1-6.  He used a muffin tin so that they ice blocks wouldn't touch or affect each other.

Then he got the cups out of the freezer and cut the plastic cup away from the ice block.  Then he measured each ice block to get a starting point.  Each block was 2 3/4 inches tall.

Then on to the experiment.  He added the following to each ice block:

#1 CONTROL - he didn't do anything 

#2 HOT WATER - poured 1 Tbsp hot water over the ice block
#3 SUGAR - poured 1 Tbsp sugar on top of the ice block
#4 SALT - 1 Tbsp salt on the ice block
#5 VINEGAR - 1 Tbsp room temperature vinegar poured on ice block
#6 BAKING SODA - 1 Tbsp baking soda on the ice block

After 20 minutes, he measured the ice blocks.  #2, the hot water block was noticeable smaller than the others.

Another 20 minutes went by and he measured again.

Every 20 minutes he measured the ice blocks until one of them had disappeared.  It took 160 minutes.

Here is the graph that combined the results:

Then he combined his research, his graph and some pictures onto his poster board.  The Mom in me wanted to step in at this point and make the poster a little more organized, but I actually refrained. He was quite pleased with his project and his board.

If you do this experiment, did you get the same results?