L13. Smells

Lesson OutcomesAPP AF4

HSW 1c,2c,3a,3c

How I did Targets

Task 1: Recognise that some cosmetics are made from natural sources.

Grade C

Task 2:Understand that some cosmetics are synthetic and describe how an alcohol and acid can be reacted to make an ester for use in perfumes.

Grade B

Task 3: Recall that perfumes have a pleasant smell and describe or explain the other properties they need.Explain their volatility in terms of kinetic theory.

Grade A/A*

Connector:

Explain how emulsifiers work

Using additives

BIG picture

• What skills will you be developing this lesson?

• ICT• Numeracy• Literacy• Team work• Self management• Creative thinking• Independent enquiry • Participation• Reflection

• How is this lesson relevant to every day life? (WRL/CIT)

SmellsSmells

•Air freshener.•Soap.•Shampoo.•Washing up liquid.•Moisturiser.

• Name 5 things that have perfume added to them.

New Information for Task 1

• Cosmetics substances used to change a persons appearance or smell for the better

• Cosmetics may be artificial or synthetic

• For example: skin creams may contain polyethylene glycol rather than plant oils or glycerine

What do you think the first cosmetics and perfumes were made of?

•Plants•Flowers•Ground up rocks

Do we still use these today?

Now lots of our cosmetics andperfumes are ‘synthetic’ – meaning human made. i.e. Not natural anymore.

Task 1 (Grade C)

• Task 1:• Name two natural sources of

perfume

Task 1: Review

Lesson Outcomes How I did Targets

Task 1:

Grade C

Met?

Partly met?

Not met?

How can I improve on task 1?

Go back to your lesson outcome grid and fill out the ‘How I did’ and the ‘Targets’ column.

New Information for Task 2

• Perfumes are substances with pleasant smells.

• Perfumes need certain properties to allow them to work properly.

• Q: what are these properties and why is each property important for a perfume?

• Explain why a perfume should not react with water or dissolve in it.

Perfume properties

• For a perfume to be good it needs to have a few important properties:

oEvaporate easilyoNon toxicoDoes not react with water (sweat)oDoes not irritate skinoInsoluble water.

Task 2: Review

Lesson Outcomes How I did Targets

Task 2:

Grade B

Met?

Partly met?

Not met?

How can I improve on task 2?

Go back to your lesson outcome grid and fill out the ‘How I did’ and the ‘Targets’ column.

They evaporate and go into our nose – there they stimulate sense cells that send messages to the brain.

How do we smell perfumes?

How do they evaporate?

Perfumes are made of alcohols. Many alcohols evaporate much quicker than water. The heat from our skin or from thesurrounding environment can make the alcohol evaporate, taking the perfumes smell with it.

New Information for Task 3Volatility: is a measure of how easily a liquid evaporates

• Molecules in liquid are attracted to each other• They must overcome these forces to evaporate • Molecules with lots of energy can do this• Perfumes evaporate easily and attractions between molecules are weak and easily overcome

Esters

Alcohol + acid ester + water

alcohol organic acid ester made smell of ester

pentanol ethanoic acid pentyl ethanoate pears

octanol ethanoic acid octyl ethanoate bananas

pentanol butanoic acid pentyl butanoate strawberries

methanol butanoic acid methyl butanoate pineapples

Task 3: (Grade A/A*)

• Task 3:

1. Explain how we can smell perfumes

2. What are esters?

3. What is needed to make an ester?

4. How is ethyl methanoate made?

5. Explain in terms of particles, why a perfume may smell stronger once applied to the skin.

Keywords for Task 3:

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Task 3: Review

Lesson Outcomes How I did Targets

Task 3:

Grade A/A*

Met?

Partly met?

Not met?

How can I improve on task 3?

Go back to your lesson outcome grid and fill out the ‘How I did’ and the ‘Targets’ column.

Review of lesson

• True or false activity

Homework

• Homework task:

• Due date:

• Criteria for Grade C:

• Criteria for Grade B:

• Criteria for Grade A/A*:

Technicians’ List

Bunsen burner, mat, tripod and gauze • test tube rack • test tube containing 1 drop of concentrated sulfuric acid • test tube holder • 250 cm3 beaker •

timer • access to pure ethanoic acid (corrosive), butanol (harmful) • 100 cm3 beaker containing 20 cm3 0.5M sodium carbonate solution (low hazard)