Do not let your kids eat the hail or drink the rainwater. It is likely to contain some benzene and cyclohexane. Can it rain oily compounds? The short answer is it certainly can. It is also not complex to work out which chemical compounds will be coming down in our rainwater. It is those with a similar boiling point and freezing point to water. It is those that are not too heavy, that are similar to that of air at 1.2 kg per cubic meter. They should be able to rise easily to upper atmospheric levels.

Let us start with water. On earth at everyday working temperatures matter has 3 phases. They are solid, liquid and gas. We know these phases by other names called ice, water and steam.