Machined aluminum cylinder floats in cold water, but sinks in warm water. Includes activity guide. Measures 0.65" diameter x 3.5" long. Weight is 0.5 oz. Additional Info: Machined aluminum cylinder floats in cold water, but sinks in warm water. Includes activity guide. Measures 0.65" diameter x 3.5" long. Weight is 0.5 oz. Package Size(L x W x H): 3.5 X 0.75 X 0.75 (IN) Categories: Matter, Density HTS Code: 7326.90.8588 UNSPSC: 6.01e+007 Country Of Origin: INDIA