Smells Unit

1. Smells Unit Investigation I: Speaking of Molecules Lesson 1: Cat Food and Stinky Cheese Lesson 2: Sniffing Around

2. Smells Unit – Investigation I Lesson 1: Cat Food and Stinky Cheese

3. ChemCatalyst • What does smell mean? Write a definition. • Why do you think we have a sense of smell? Unit 2 • Investigation I

4. The Big Question • How do we talk about smells? • The Goal: • To be able to categorize smells. Unit 2 • Investigation I

5. Activity • Purpose: This lesson introduces the study of smell, which runs throughout the unit as a theme. By the end of the lesson you will be acquainted with five different smell categories that are used for identifying and grouping odors. • Safety Note: Any student having chronic respiratory problems should not be involved in the smelling portions of these activities. Another student in the group can act as that student’s “nose.” Unit 2 • Investigation I

6. Instructions • This is a two-part activity. In this first part you will smell a variety of household substances and describe their smells. • Record the smells in the following data table in one or two words. Avoid using words like bad, stinky, weird, etc.. • Copy the following table into your notebook. Unit 2 • Investigation I

7. Safety Note: In the chemistry laboratory it is NEVER recommended to sniff from a bottle directly, even if a substance is presumed to be safe. It is expected that students will use the wafting technique from now on whenever they are asked to smell anything in a chemistry classroom. (cont.) Unit 2 • Investigation I

8. Notes(cont.) • Wafting is a technique of using your hand to draw air over the opening of a container in the direction of your nose. Air mixed with the substance is drawn into your nose so that the smell from the original substances is diluted. (cont.) Unit 2 • Investigation I

9. Title: Cat Food and Stinky Cheese Purpose: To become familiar with the 5 different smell categories. Part I Unit 2 • Investigation I

10. Part II • Look at the smell descriptions and group similar smells together. List the numbers of the substances that smell similar. • Record your groupings in your notebook in a new table. • Example: Category 1: Minty Vials: 1, 2 Category 2: Vials:

11. Part III • Smell the 5 mystery smells and classify them using your new smell classifications: • Copy this table into your notebook: Unit 2 • Investigation I

12. Analysis: Cat Food and Stinky Cheese • Describe some difficulties that arose in trying to find works to describe the substances. • Was there anything that didn’t smell at all to someone? • Into which categories would you put the following smells? 1) banana 2) peanut butter 3) rotten egg 4) shampoo Unit 2 • Investigation I

13. Notes • Smell classifications are general terms that describe a group of smells. Unit 2 • Investigation I

14. Notes • Putrid is a word that describes things that smell quite repulsive. Dead animal or really old leftovers from the refrigerator smell putrid. • Camphor is a word used to describe things that smell pungent and medicinal. Camphor is a substance and a word used back in your grandparents’ day. The smell of camphor is quite distinctive. Bengay or Vicks Vapor Rub smell like camphor. (cont.) Unit 2 • Investigation I

15. Notes(cont.) • Sweet smells include things that are flowery and fruity smelling. • Minty is a green herbal smell that most people are very familiar with and doesn’t usually require explanation. • Fishy smells are very distinctive and don’t usually require an explanation. Most seafoods smell fishy. (cont.) Unit 2 • Investigation I

16. Notes(cont.) (cont.) Unit 2 • Investigation I

17. Notes(cont.) Unit 2 • Investigation I

18. Wrap-Up • Scientists have come up with words to classify smells, which include minty, fishy, sweet, putrid, and camphor. Unit 2 • Investigation I

19. Homework: Lesson 1 • Name two things you have learned about smell so far. • Lit the names of 8-10 substances at homes that fit into the 5 smell categories (minty, fishy…) • Name 5 substances that do not fit into the 5 categories. What new categories would you put them in? • Make a list of 5 things that have no smell. • What makes something smell the way it does? • Describe a memory that relates to smell. Describe the smell and the memory. • How do you think taste is related to smell? Unit 2 • Investigation I

20. Smells Unit – Investigation I Lesson 2: Sniffing Around

21. ChemCatalyst • What do you think your nose is detecting when it smells something? What evidence do you have to support your answer? Unit 2 • Investigation I

22. The Big Question • What does chemistry have to do with smell? You will be able to: • Predict how a molecule will smell based on its molecular formula. Unit 2 • Investigation I

23. Activity • Purpose: In this lesson you will start to explore the connection between chemistry and smell. You will be given the molecular formula and chemical name of the five mystery substances that you smelled in Lesson 1. (cont.) Unit 2 • Investigation I

24. Examine this information in order to look for a chemical relationship to smell. Write your predictions in your notebook. Unit 2 • Investigation I

25. Making Sense • Is there any evidence that smell, molecular formula, and chemical name are related? Unit 2 • Investigation I

26. Notes: Predict what category(s) of smell will include the following chemicals. Write this in your lab notebook by extending your previous data tables. Explain why you put them in those categories. Unit 2 • Investigation I

27. Here are the actual smells. Complete your data table. Unit 2 • Investigation I

28. Check-In • How would you expect a molecule with the molecular formula C8H16O2 to smell? Explain. Unit 2 • Investigation I

29. Wrap-Up • Smell appears to be related to molecular formula and chemical name. • Molecular formula alone is not always sufficient to predict smell because molecules can have the same molecular formula but different smells. Unit 2 • Investigation I