Volume thermal expansion?

A solid aluminum sphere has a radius of 0.50 m and a temperature of 75 C. The sphere is then completely immersed in a pool of water whose temperature is 25 C. The sphere cools, while the water temperature remains nearly at 25 C because the pool is large. The sphere is then weighed in the water immediately after being submerged (before it begins to cool) and then again after cooling to 25 C. Which weight is larger? Why? Use Archimedes' principle to find the magnitude of the difference between the weights.