A relatively simple inquiry- based activity that I have done with several classes involves predicting and then observing the comparative speed with which ice melts. In younger classes, I tend to keep the predictions fairly simple. The children will predict which will melt the ice more quickly, warm or cold water. With older classes (usually 3rd class and up), I have added some complexity. With this activity, we have four bowls of ice (usually I colour the ice with food dye and use molds to make the ice into interesting shapes). One bowl is left alone completely and the second bowl of ice has salt added to it. The third bowl has the ice in fresh water and the fourth bowl has the ice in salt water. The children are then asked to predict the order in which the ice in the bowls will melt. Usually, there is a mix of predictions, with some children believing the water will make the ice melt more quickly, while others predict it will make the ice melt more slowly. However, nearly always the general consensus is that salt will make the ice melt more quickly. This is true for the first and second bowls, as the salt will melt the ice in the second bowl more quickly than the ice in the first bowl. However, interestingly, the ice will melt more slowly in salt water than in fresh water. This realisation makes the class discussion on our conclusions very interesting, as the children develop an understanding of how different properties and circumstances can affect how materials react to their environment.