Sand, gravel, and pebbles come in many different sizes and is an important property of rocks. 1. Tap the button. 2. Using the tools, draw each type of rock. 3. Using the or tool, draw or write what you could make from each type of rock. 4. Tap the when you are done to add to your journal. CHALLENGE: Make a creation using all three types of rock. Take a picture of your creation and upload it to this page.