Final answer:
The Law of Conservation of Matter states that matter cannot be created or destroyed. When the Grinch burns down the tree, it does not disappear; it changes form, with part of its mass turning into gases released into the atmosphere and a portion remaining as ash.
Step-by-step explanation:
Even though the Grinch burns down the Christmas tree in Whoville, matter is not destroyed, as dictated by the Law of Conservation of Matter. This principle tells us that the total mass of matter remains the same before and after a chemical reaction, such as burning. When the Christmas tree burns, it reacts with oxygen and is transformed into different substances, like carbon dioxide, water vapor, and ashes.
For instance, if a tree weighs 300 kg before burning, and afterwards the ashes weigh 10 kg, one might wonder where the remaining 290 kg went. According to the Law of Conservation of Mass, this mass has been released into the atmosphere as smoke and gases. So, while the tree is no longer in its original form, the matter that composed it still exists, just in a different state.