On the Rocks

Doing science always begins with making observations. Rocks are a collection or mix of minerals, which are pure elements or compounds in crystal form, that are bound together by a natural cement, usually the compound silicon dioxide. Look at the collection of rocks in your group’s box and answer the questions below.

1. Give a description of each rock (color, texture, weight, size, big or small crystals).

2. What are some similarities among the rocks?

3. What are some differences between the rocks?

4. Sort the rocks into 3 piles based on some criterion of similarity. What were the criteria you chose to group the rocks?

5. Where do rocks come from? Did all these rocks come from the same place? Where do you think each of these different these rocks came from?

6. How are rocks made? Were these rocks all made the same way? How do you think these rocks were made? Do you think some of the rocks were made in different ways from the others? How old are your rocks?

7. Any rock can be placed into one of three general categories of rocks: igneous (cooled from liquid rock), sedimentary (rocks that form from pieces of other rocks usually at the bottom of rivers or the ocean or rocks that form from dissolved minerals also in water), and metamorphic: rocks that are changed into new rocks under great pressure and heat while buried underground for millions of years. Can you determine which aof your rocks are igneous, sedimentary, or metamorphic?

Making observations leads naturally to questions. When a scientist asks a question about something, like where do rocks come from or how old is a particular rock, he or she will usually think of a possible answer to his or her question. Scientists then use the scientific method to test their possible answer to their question. Do you know the scientific term for a possible answer to a scientific question that can be tested with the scientific method? Write it below.