 Let's see if temperature affects the rate of reaction. What I have here is a glow stick. You're familiar with glow sticks. You know there's two chemicals, and if we break the little glass ampule in the center, the two chemicals mix and we get a glow. I'm going to place one in hot water and one in cold water. And then we'll observe what happens. The brightness is indicative of the faster rate of reaction. The brighter it glows, the faster the reaction has taken place. Let's look at our glow sticks after half an hour. Remember this is the hot and this is the cold. Let's look at the brightness. After half an hour you can see that the glow stick in the ice water is glowing brighter than the one in the hot water. And the reason for this is that the reaction occurred much more quickly in the hot water and it's already gone to completion.