When geologists study a rock, they examine its shape, size, texture, and color. They consider where the rock was found, too. But they also study things they can’t see, like a rock’s hardness. Geologists use special instruments to test rocks in the lab.

Now it’s your turn to examine the rocks you found. After you record your observations, sort them into different categories. You can organize them by physical traits, like shape or color. You can also organize them by where they were found.

Be sure you have your Rock Chart, your rock samples, a pencil, and a big place to work. Spread out your rocks on the table or floor.

Now take the rock out of its bag. Look at it closely. Turn it around in your hand. Feel its texture. As you examine the rock, consider the different traits below. As you do, record your observations in your Rock Chart.

• Size: How big is it? Think of something about the same size, like an apple or a kiwi.
• Color: What color is it? Is it the same color all over, or is there a mix of colors?
• Texture: How does it feel? Is it smooth, rough, or bumpy?
• Shape: What shape is it? Is it flat? Round? Does it have sharp edges? Think of something with a similar shape, like a lemon or a strawberry.

Now try sorting your rocks into a few different categories. You might organize them by physical characteristics, like color or texture. Or you could organize them by where they were found.

Next, choose one way to organize your rocks. Then decide how you would describe each group. For example, if you organized your rocks by size, you might put them into three groups: large (size of an orange or bigger), medium (about the size of a kiwi), and small (the size of a strawberry or smaller). Or if you organized them by where they were found, the groups might be: at the park, near the lake, and in the backyard.