So, the answer to your question is that for equal mass of Steel and Aluminum, Aluminum will remain cooler for longer as it requires more energy per unit mass to heat up than steel. As you can see, Copper heats up about 2 times faster than Aluminum, but 13 times faster than steel.

The iron holds more thermal energy than the brick. Both blocks lose their thermal energy into the air. When the iron block is placed in the water, its thermal energy is transferred to the colder water. The water is heated up as the iron cools down.

Does aluminum or iron heat up faster? Iron is much denser than aluminum, so any heat it accumulates tends to take longer to dissipate due to radiation or conduction. Aluminum is one of the lightest metals, and looses heat rapidly due to both those factors. Iron has about twice the “atomic weight” of aluminum…

Can You Melt Pennies and Nickels? Because of the rising price of nickel and copper that began in 2005, the United States passed a law that made it illegal to melt pennies and nickels for their metal content. Replacing these coins would be an enormous cost to taxpayers.”

5 United States Coins You Can’t Own

• 1866 No Motto Seated Liberty Quarter. Seated Liberty Quarter enthusiasts spend years, even decades, seeking a few dates that are extremely rare and small in number.
• 1866 No Motto Seated Liberty Half Dollar.
• 1804 Class II Draped Bust Dollar.
• 1849 Liberty Head $20 Double Eagle.

It is not illegal to melt, form, destroy, or otherwise modify US coins, including pennies, unless the objective is fraudulent or with the intent of selling the raw materials of the coins for profit. Projects that use coins as materials are entirely legal in the United States.

4 It contains about 2.95 grams of copper, and there are 453.59 grams in a pound. 5 The price of copper on Dec. 10, 2019, was $2.75 a pound. 6 That meant the copper in each penny was worth about 1.7 cents.