We have a lot of intriguing things to see in Arizona, especially for families interested in rocks, geology and earth science.
The Petrified Forest National Park is an excellent example. It is found in the northeastern area of the state.
The visitor is greeted by great logs that look like they have been carved from stone.
The different pieces come in a rainbow of colors.
You soon learn that petrified wood forms under special circumstances that allows minerals to seep into the cells of the wood and harden. Iron oxide makes the petrified wood look red or orange (rusty), whereas manganese oxide produces blues, purples or black. Other compounds may cause the petrified wood to be greenish or yellow.
If you have a piece of petrified wood (often available at rock shops), look at it with a hand lens. See if you can identify the tree rings, or other structures that were parts of the original tree. A few of the logs we saw had remnants of bark.
Sometimes you can identify the type of tree the wood came from. For example, the Texas State Stone is petrified palmwood, coming from a petrified palm tree. (Technically a fossil, petrified wood is also Arizona’s state fossil.)
For more information and activities, try:
Rockin’ Through the Ages: From Fossils to Petroglyphs Curriculum at the Petrified National Park website (free .pdf files) Examples include making a personal timeline. Fun!
Make a permineralization fossil using wax and a sponge (from Bryce Canyon National Park)
Petrification cycle activity (activity is towards the bottom)
Loose in the Lab post about petrified wood
Your Gemologist has a child-friendly discussion of how petrified wood forms
Have you ever been to the Painted Desert?