Combustion

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com. Why don’t rocks burn? – Luke, age 4, New Market, New Hampshire While many rocks don’t burn, some of them do. It depends on what the rocks are made of – and that’s related to how they were formed. There are three main rock types: igneous, sedimentary and metamorphic. These rocks are made of minerals that all have different characteristics. Some will melt into magma or lava – super-hot, liquid rock – when they are exposed to heat. Others will catch fire. Rocks can look alike, but one rock is not like another. Rocks that burn when they get heated up are combusting. This means that elements within the rocks are reacting with oxygen in the air to produce heat a...