To accompany ‘How curving ice needles sculpt natural rock art’  

SCIENCE

Before Reading:

1. Imagine an icy winter morning. Based on either your own experience or what you may have seen in movies, describe three different ways ice may appear. Compare the ice in terms of shape and texture. For example, how does ice that formed along the edge of a roof appear? How might ice that formed on the ground appear?
   
2. A student puts a water bottle into the freezer. The water becomes ice, and when the student retrieves the bottle later, she observes that the bottle bulges outward. The water bottle did not bulge before freezing, only after. Based on that observation, what must be different between the water as a liquid and as ice? Regarding the amount of space taken up, what changes does water undergo as it freezes? Complete this simple statement to describe this change: “As water freezes…”

During Reading:

1. The rocky patterns described in this story result from water undergoing what kind of change?
   
2. What are “ice needles”? Describe the conditions that must be present for “ice needles” to form.
   
3. Throughout many freeze/thaw cycles, what changes did Bernard Hallet’s team observe in the frequency of ice needle formation? Where did they occur more often? How does Hallet explain that change in frequency?
   
4. In the context of this story, what is a “model”? What are the scientists using this model to do? List three environmental conditions that this model accounts for.
   
5. Explain why Anyuan Li’s team calls this experiment “a time machine in which they can push the fast-forward button.”  
   
6. Explain the how ice needles manage to push stones aside over time.
   
7. Li’s group showed that the action of the ice needles separated “two phases.” What were those “two phases”?
   
8. What kind of scientist is Rachel Glade? What does she study? In what way does Rachel hope that this study could improve understanding in her own field?

After Reading:

1. Imagine you are a scientist that wants to study how stone patterns form in a particular landscape. That landscape is cold and rocky, like those discussed in this story. When you arrive, what kinds of landscape features would you examine? Use what you learned in this story to explain your answer. If you were able to study this landscape for an entire year, what measurements could you take that would most improve your understanding of the stone pattern formations in this region? 
   
2. Over time, new soil layers form atop old soil, creating layers called strata. Geologists study a landscape’s strata to learn what that landscape was like thousands or even millions of years ago. You’ve probably seen strata along mountain roads where soil or stone was sliced away to make space for the road. How might a geologist studying strata use the study described in this story to understand past environments better?  What might that geologist look for in geological strata, and what new insights might it yield? Use examples from this study to support your answer.