![]() Depending on the type of steel, steel can have a strength of anywhere between 3 megapascals. If we look at the hardness of copper, depending on how it’s treated, it can have a strength of anywhere between 200 and 350 megapascals. ![]() So, as long as the material is strong enough, having a higher strength is not going to make a great deal of difference. ![]() Roofs don’t support very much mass themselves, apart from their own weight. For most roofs, having a high strength isn’t really an issue. Therefore, this is an incorrect answer.įinally, we come to the last option, having a higher strength. So, saying that copper has a higher melting point than steel is not even true. However, steal depending on the type of steel, can have a melting point much higher between 1425 degrees Celsius and 1540 degrees Celsius. Copper has a melting point well above that at 1085 degrees Celsius. The hottest outside temperature ever recorded was 56.7 degrees C, recorded in Death Valley, California in 1913. What would be the benefit of having a roof with a higher melting point? As long as the melting point of the roof is above ambient temperature, it’s probably not important what the melting point is. However, to be safe, I’m going to look at the last two options as well. So, having a higher corrosion resistance would confer a major advantage on copper over the use of steel when used as a roofing material. Most forms of steel are alloys of iron and carbon while stainless steel also contains a high proportion of chromium. Stainless steel would resist corrosion but it’s much more expensive than regular steel. Remember that the question refers to steel and not to stainless steel. It does not react with acid, for instance, in acid rain, and is very slow to oxidise. A roof with higher corrosion resistance will last longer and resist the elements. This is a very good feature for a roof material. Next, we have higher corrosion resistance. So, the difference between their densities would likely be quite small and would confer a small advantage at best. Since they’re both in the transition metal block, their densities would be similar. If you looked at your periodic table, you’d see that copper and iron are in the same period of the periodic table. Therefore, this too is an incorrect answer.įor this question, you wouldn’t necessarily have to look up the densities for copper and steel. ![]() So, it does not have a lower density, and therefore, it cannot be an advantage. This means copper is actually more dense than steel. Copper has a density of 8.96 grams per cubic centimetre while steel, depending on the type, has a density of about eight grams per cubic centimetre. What about a lower density? All else being equal, using a lower density material will make the roof lighter, making it easier to install and putting less stress onto the rest of the building. However, as we’ve mentioned even though the thermal conductivity of copper is higher, this is not an advantage when it comes to building a roof. Copper displays a thermal conductivity about five times higher than that of iron. Steel is mostly iron, so we can compare the thermal conductivities of copper and iron. So, having a material with a higher thermal conductivity will actually make that worse. Heat is lost from the inside of a building to the outside world, some of it through the roof. Option A, having a higher thermal conductivity, does not make a great deal of sense for a roof. ![]() One of the most important features of a roof is that it protects the building from weather, particularly the rain. What the question is looking for is an advantage that’s pertinent to the application of the metal to roofing. Which of the following is a major advantage of copper over steel when used as a roofing material? A) Higher thermal conductivity. ![]()
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