This week in science we learned that crystals form when lava cools. If the lava cools quickly there will be smaller crystal. If the lava cools slowly the crystals will be larger. We also learned that air bubbles are formed from trapped air in the rock as it cools. On Wednesday we melted moth balls and put them in cold, hot, and room temperature surfaces. On Friday we observed the results of the test. After the test we saw that there was bigger crystals in the hotter surface than in the colder surface. In the hotter surface there were less air bubbles. In the room temperature surface we found that it was a combination of both the cold and hot surfaces and there were a small amount of air bubbles. In the cold surface there were almost no crystals and a lot of air bubbles. Also this week we learned that the colder surface has more air bubbles than the hotter surface. One question I have is how can we determine the age of rock layers?