Accessing Prior Knowledge About Snow and Salt

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Accessing Prior Knowledge teacher's guide

TEACHER'S GUIDE

Introduce the unit by accessing student prior knowledge about snow and salt.

Discussion

Key Idea: Snow interferes with daily life, so humans use salt to limit its interference.

Question:  What are your experiences with snow in NYC?
Answer:  The snow piles up, over time becomes dark and dirty, and stays like that until it melts away down storm drains.  

Question:  What does the City look like during a snowstorm? After a snowstorm?
Answer:  The City is covered with snow. It is very hard to get around.  Slowly life gets back to normal.

Question:  How do people deal with snowy and icy roads or how do people help life get back to “normal”?
Answer:  The streets are plowed, sidewalks shoveled, and sand and salt is put on roads and sidewalk.

Question:  Why is salt used on roads?
Answer: Salt helps to melt the snow because it lowers the freezing point of water (see the Teacher Tip on colligative properties for more information).