February Fashion Teaching Material

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The Chemistry Calendar Theme: Fashion

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FEBRUARYFASHION

Chemical research is important to make new materials that can improve our daily lives in anumber of different contexts, and fashion is not an exception.

The February video Dress up in polymers starts with something that is well-known to most

people GoreTex. How does it work? And what is a polymer? The video shows through

some examples how common polymers are in clothes.

This folder includes background info for the video and some classroom experiments, with

teacher notes.

CONTENTS

Dress up in polymers ............................................................................................................................................... 3

Make your own body lotion .................................................................................................................................... 7

Teacher notes ...................................................................................................................................................... 7

Lab instructions ................................................................................................................................................... 8

Growing crystals ...................................................................................................................................................... 9

Teacher notes ...................................................................................................................................................... 9

Lab instructions ................................................................................................................................................. 12

Functional materials .............................................................................................................................................. 15

Teacher notes .................................................................................................................................................... 15


Making gold ........................................................................................................................................................... 18

Teacher notes .................................................................................................................................................... 18


Creating a scent..................................................................................................................................................... 20

Teacher notes .................................................................................................................................................... 20



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DRESS UP IN POLYMERS

When you hear the words fashion and beauty, chemistry is probably not the first things that

comes to mind. The fact is, however, that chemistry has played a major role in mans hunt

for improved appearance. Take all the skin care products, for example. There is much

chemistry going on behind these, as they are supposed to have softening, moisturizing and

sometimes even anti-aging properties. Smelling good is also something that is closely

connected to chemistry, as perfumes are composed of different molecules with varying

structure in order to generate various scents. Combining chemistry and textiles is something

that has caught a lot of attention lately. Why not let a nice sweater also have cooling

properties on a hot summer day? Why not let your fancy curtains glow as the room becomes

dark in the evening? Indeed, chemistry has found and will continue to find new and exciting

uses in todays modern society!

WHAT IS A POLYMER?

A polymer is a chemical compound that consists of many repeating smaller units, so called

monomers. You can think of a polymer as a necklace, where each pearl is a monomer.

Depending on which type of monomer and in which order and how the monomers are puttogether, the polymer can have different properties. Several Nobel prizes in Chemistry have

been awarded to scientists working in the field of polymers. In 1953, Hermann Staudinger

received the Prize for showing that polymers exist. In 1974, the Prize was awarded to Paul

Flory for, among other things, his studies on how a polymer is formed. In 2000, the Nobel

Prize in Chemistry was awarded to Alan J. Heeger, Alan G. MacDiarmid och Hideki Shirakawa

for their discovery that plastics can conduct electricity. Polymer science is clearly an exciting

research field, and there is still much activity going on.

Polymer of repeating units, monomers.


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SYNTHETIC POLYMERS

Plastics are a form of synthetic polymer. By varying the type of monomer that builds up the

polymer and by attaching various molecule groups on the polymer chain, the material canhave very different properties. Plastics can be soft, hard, water soluble, water proof, elastic

and endure high temperatures. Because of this, plastics have found a variety of uses in a

number of different types of industry, such as packaging, building and automotive industry.

Nylon is another example of a synthetic polymer that is formed in the interface between two

different liquids. The solutions contain hexamethylenediamine and sodium hydroxide in

water, and sebacoyl chloride in hexane. A continuous reaction is the result and the product

is a long polymer chain.

The chemical structure of two different types of plastic. Polyethylene (left) is very elastic while polystyrene

(right) is hard and rigid. Everything that is within the parenthesis is repeated many times (n), thus forming a

polymer.

NATURAL POLYMERS

In every cell in the body, there is a natural polymer in the form of DNA, our genetic code.

DNA is build of millions of nitrogen bases, that together form the characteristic DNA helix.

The DNA codes for all the proteins in our bodies. These proteins are also biopolymers, as

they consist of a combination of 20 different amino acids that together for a single, long

chain.


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The four building blocks of the DNA helix: thymine, adenine, cytosine and guanine.

Silk is another natural polymer, that is formed by the larvae of the silk worm, as they spin

cocoons out of a long single strand of silk thread. Silk is known for its luster, appearing to

have different colors depending on which angle you look at it. This is due to the triangular

shape of the fiber. When light hits the polymers, it spreads at different angles It is also an

elastic material that can be stretched and then will recover to its original size.

GORETEX

GoreTex is a special membrane that consists of a network of the polymer Teflon, also called

polytetrafluroethylene, PTFE. The structure of this network forms tiny pores allowing water

to pass only in the form of vapor. Water droplets, which are considerably larger than single

water molecules, cannot cross the membrane. This makes GoreTex able to transport sweat

away from our bodies while water in the form of e.g. rain or snow is kept out. It was in 1978

that Wilbert L. Gore invented GoreTex technology and since then the interest in this type of

material has increased steadily.

Water vapor (sweat) is transported through the network of polymers in the GoreTex membrane. Water droplets

cannot pass the membrane, making the material water proof.


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OTHER USES

GoreTex is actually used not only as functional material in jackets, shoes, pants etc. It is also

used as cable material in among other things submarines, printers and brain probes.Surgeons use this polymer technology to make artificial tissue due to its strong,

biocompatible properties. A natural artery can be replaced by GoreTex membrane, which

can deal with the high blood pressure without tearing. These are just a few examples of the

different uses of GoreTex material and we can expect more clever applications in the future!

TEXTILES OF THE FUTURE

How about having a microphone in your glove, measuring your pulse and immune system

with the aim of a sweater, having curtains that glow in the dark? These are a few examples

of textiles for the future already available on the market today. Research projects like Smart

Textiles in Bors, Sweden, combine technology and textile material, and collaborations

between many research groups will result in materials that we never would have thought of

as possible...

A sweater that can measure EKG data. Photo: Jan Berg


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MAKE YOUR OWN BODY LOTION

TEACHER NOTES

For whom? All ages

Throughout history, man has looked to improve appearance in various ways. The Egyptians

used castor oil for hair treatment, and the Romans made body lotions from beeswax, olive

oil and rose oil. Beauty products have always had a pleasant scent, most likely in order to

hide the fact that people did not wash frequently and that soap was not used until the

Middle Ages and few had access to this luxury. Today, body lotions are most often used to

moisturize the skin after washing, resulting in a comfortable feel.

This body lotion does not contain any preservatives, which means that it should be used

shortly after making it. The use of bee wax increases its durability somewhat.

Beeswax consists of myricin (about 65 weight per cent), a mixture of esters, long-chain

alcohols and carboxylic acids. The worker bees produce bee wax from glands under their

abdomen. After honey has been collected, beeswax and remains of honey can be separated

by boiling the frames from the hive, making the beeswax float on top.

The beeswax in the body lotion provides skin coating, which gives the skin a certain luster,

prevents water evaporation and protects it from being affected by water from the outside.

The olive oil softens the skin and can enter the outermost layer of the epidermis.

It is possible to further develop this experiment to make lipstick or cerate.


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MAKE YOUR OWN BODY LOTION

LAB INSTRUCTIONS

You need:

Oliv oil Almond oil or high quality sunflower oil Beeswax

(Optional) Aroma oil and food color A saucepan with boiling water or a hot water bath

Procedure:

1. Mix one part beeswax with three to four parts olive oil in a bowl. Divide the beeswaxin smaller pieces to speed up the mixing.

2. Put the bowl in the water bath to make the beeswax melt slowly. If the solutionbecomes opaque you can let it pass through a tea sieve. Adjust the viscosity withmore oil to make it more liquid or more wax to make it thicker.

3. Stir the lotion while it cools to make it smooth.4. (Optional) Add a few drops of aroma oil as the lotion cools, if you want it not to smell

honey. If you also want to change its color, you can add a few drops of food color.

5. Put the lotion in small jars with lids.

Things to discuss:

Where does beeswax come from and what is its function in Nature?

Why does your skin feel softer if you use this lotion?


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GROWING CRYSTALS

TEACHER NOTES

For whom? All ages.

Depending on how old the students are, the difficulty of the theory part can be

adjusted. The experiments can be performed as group projects. The students

can then divide the responsibility of handling the crystal so that everyone

makes a contribution. The experiment can also be performed individually, but

assisting every student in the first part of the experiments (dissolving the salt)

means a lot of work. The experiment covers solubility, evaporation,solid/liquid/gas.

Most kids are fascinated by crystals. They are both beautiful to look at and mysterious. Who

hasnt heard stories of the seer looking into the future in a crystal ball. In this experiment,

the students get to make their own crystals using a simple method. They will observe how a

solid is dissolved and returns to solid state as the liquid evaporates crystals are formed.

A crystal is a solid that consists of atoms, ions or molecules arranged in a unified pattern.

This gives the crystal a specific shape, color or other characteristic properties. Diamond and

graphite are two examples of crystals that are both made up of the element carbon but very

different thanks to the differences in structure.

Recrystallization is a method used to purify solid material dissolving it in a liquid and then

letting the liquid evaporate to make the material crystallize. Depending on the procedure

used, it is possible to achieve many small crystals or a few large ones.

There are different types of crystals, depending on the positions of the chemical bonds and

thus the shape of the crystal. Seven different crystal shapes (lattices) exist, e.g. cubic,

tetragonal and hexagonal. You can also categorize crystals according to their chemicalproperties.

Covalent crystal one large molecule, e.g. diamond, with a very high melting point Metal crystal Ionic crystal, e.g. NaCl the atoms are held together by electrostatic bonds. Hard

crystals with a relatively high melting point

Molecular crystals Molecules that are connected through weaker bonds like vander Waals bonds or hydrogen bonds, e.g. sugar. These crystals are softer and have

lower melting points


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There are crystals that are made artificially as well as crystals that are formed in a natural

way, e.g. the mineralsquartz,diamondandcorundum(corundum exists in the two variants

sapphireandruby). Even a snoflake is a type of crystal an ice crystal.

HABITUS

The crystals can assume different shapes, habitus. What shape

a crystal assumes depends on how fast the different surfaces of

the crystal grow compared to each other. The surfaces of the

crystal can be looked upon as cross-sectional areas that can be

drawn in various ways through the crystal. Alum belongs to the

cubic crystal system and its habitus has the shape of an

octaeder.

Examples of crystals from the cubic crystal system. The crystals can assume different shapes, habitus.

Alum crystals resemble the shape to the right.

Illustration: Svante berg, Ume University

ALUMAlum (hydrated potassium aluminium sulfate, AlK(SO4)212 H2O) is a double salt (contains

both potassium and aluminum). Alum is the most well-known double salt but the potassium

can be exchanged for another large monovalent ion, e.g. Cs+, NH4

+or Rb

+and the aluminum

can be exchanged for a relatively small trivalent ion, e.g. Cr3+

, Fe3+

or Co3+

.

The crystal that is grown in this experiment crystallizes in the cubic system, as an octaeder

just like Alum. Due to their shape, it is rather easy to achieve large crystals when you grow

them yourself.

MANUFACTURING AND USAGE

Alum is manufactured by crystallizing a solution of potassium sulfate and aluminum sulfate.

It can be found in drug stores, and you can use it to make your own Play-Doh. It has been

used in health care, leather craft, wool dying etc. As with other sulfate salts, it can be used to

purify water. A solution of the sulfate salt is acidic. If you almost neutralize the solution with

calcium hydroxide, the hydroxide precipitates and the water is purified from contaminants

that fall to the bottom along with the precipitate.

Different crystal planes.

Svante berg, Ume University
http://webmineral.com/data/Quartz.shtmlhttp://webmineral.com/data/Quartz.shtmlhttp://webmineral.com/data/Quartz.shtmlhttp://webmineral.com/data/Diamond.shtmlhttp://webmineral.com/data/Diamond.shtmlhttp://webmineral.com/data/Diamond.shtmlhttp://webmineral.com/data/Corundum.shtmlhttp://webmineral.com/data/Corundum.shtmlhttp://webmineral.com/data/Corundum.shtmlhttp://www.mineralminers.com/images/sapphire-blue/gems/sblg114.jpghttp://www.mineralminers.com/images/sapphire-blue/gems/sblg114.jpghttp://www.mineralminers.com/images/ruby/gems/rbyg101.jpghttp://www.mineralminers.com/images/ruby/gems/rbyg101.jpghttp://www.mineralminers.com/images/ruby/gems/rbyg101.jpghttp://www.mineralminers.com/images/ruby/gems/rbyg101.jpghttp://www.mineralminers.com/images/sapphire-blue/gems/sblg114.jpghttp://webmineral.com/data/Corundum.shtmlhttp://webmineral.com/data/Diamond.shtmlhttp://webmineral.com/data/Quartz.shtml


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HOW CRYSTALS ARE FORMED AND HOW THEY GROW

In order for crystals to grow, nuclei must first be formed as a starting point for the growth.

The nuclei are formed in a process called nucleation. This process can either start with the

molecules themselves, or with the aim of some solid material that is places in the solution.

These two methods are described below.

SPONTANEOUS NUCLEATION

When the molecules of the solid that you have dissolved are in solution, they rarely

encounter molecules of the same kind. When it does happen, forces between the molecules

bring them together. Most often, they only stay in contact for a brief moment before other

forces pull them apart, Sometimes, though, they stick together long enough for a third

molecule to meet them, and then a fourth, a fifth etc. When a sufficient number of

molecules, a critical number, are gathered in such an aggregate, the forces holding the

molecules together are bigger than the forces that pull them apart. A proto crystal isformed, where the crystallization can proceed. Other molecules in solution begin to be

affected by the forces and are attracted to the crystal, which continues to grow until it can

no longer stay in solution. The concentration of the compound decreases as the molecules

that used to be in solution are added to the growing crystal. This can be avoided if the

evaporation of the liquid compensates for the disappearance of the molecules in solution.

When an equilibrium between these molecules in solution and in the crystal is established,

the crystal stops growing.

INDUCED NUCLEATION

The surface of a solid in a liquid, e.g. a rock, acts as a meeting place for molecules. The

molecules of a dissolved compound stay briefly on the surface of the solid until the forces

push the molecule away again. The molecules will form aggregates on the surface, in the

same way as described above. Proto crystals are formed and the crystallization begins. The

crystals will grow faster in a solution that is close to being saturated, since the probability of

molecules bumping into each other is larger. In a solution that is heated, the forces pushing

molecules apart are stronger, which means that the aggregates will not have time to form

until the molecules move back into the solution. This is why the crystallization does not

begin until the solution has cooled down.

Source (in Swedish): Ume universitet Skolkemi:http://school.chem.umu.se/
http://school.chem.umu.se/http://school.chem.umu.se/http://school.chem.umu.se/http://school.chem.umu.se/


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GROWING CRYSTALS

LAB INSTRUCTIONS

You need:

Alum (KAl(SO4)212 H2O) Water (H2O) 2 beakers

Spoon Thread/nylon string Stick + Play-Doh (or similar)

Procedure:

The amount of alum that is to be dissolved in water depends on the size of the crystal you

intend to grow. The alum should be dissolved until the solution is saturated, i.e. until no

more alum can be dissolved.

Preparation of a saturated solution1. Start by heating the water in a microwave safe beaker2. Dissolve roughly the double amount of alum (e.g. 1 dl water = 2 dl alum)3. Stir until everything has been dissolved4. Heat the liquid some more and check that all of the alum is dissolved. If that is

the case, add another table spoon and repeat the procedure until there isalum at the bottom of the beaker that does not dissolve.

5. Allow the solution to cool down to room temperature. This is a good time totake a break and continue later, when the solution has cooled down.

6. Now it is important to pour the saturated solution into a clean beaker. Makesure that no alum crystals are transferred. (This is important since otherwise

the crystal will form at the bottom instead of on the string. If some small


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crystal follows with the solution anyway you can add a few ml of water and

stir. This will dissolve the crystal.)

Crystal growth1. Tie the string on a small stick, e.g. a pencil. If you use nylon string, you will

have to roughen the end of the string first using a sharp object. This will allow

the crystals so stick to the string.

2. Let the end of the string hang down in the solution, right beneath the surface.3. Attach the stick to the beaker with Play-Doh4. Put a filter paper across the opening of the beaker to slow down the

evaporation.

5. Put the beaker in a dark place (to make the evaporation as slow as possible)6. After a couple of days, crystals have formed on the string. To grow a really

beautiful crystal, you have to remove all crystals but the largest/finest,

allowing it to continue to grow. Make sure that the crystal always hangs right

beneath the surface. In case a precipitate is formed on the sides of the

beaker, transfer the solution and the crystal to a clean beaker.

Now, all you have to do is wait and regularly take care of the crystal by removing unwanted

crystals, making sure that the beaker is clean and that the crystal is beneath the surface. Ifyou are lucky, in a few weeks you will have a large crystal to put in your bookshelf.

Variation 1

Begin by growing a crystal out of a solution of chromium alum, CrK(SO4)212 H2O, which

results in a crystal with a beautiful, dark violet color. Unfortunately, it breaks down at room

temperature. To prevent this from happening, move the violet crystal to a solution of alum

instead. Now, a protective, transparent layer will be formed on the crystal. The final crystal

can be stored in room temperature.

Note that Chromium(III)salts are hazardous and should be handled with care. Avoid skin

contact and spilling material on the lab bench and on your clothes. Rinse with water if you

do spill something. Chromium(III) salts should not be handled by anyone under the age of

13.

Variation 2

Can you grow crystals out of any other compounds than alum? Try table salt (NaCl) or sugar.


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Variation 3

If you are in a hurry, you can speed up the crystallization by adding a few drops of ethanol in

the salt solution. Ethanol decreases the solubility of the salt by lowering the polarity of the

solvent. But dont add to much ethanol! That makes the crystallization proceed to fast, and

the crystals will not be as regular in shape.


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Fig 2. Left: propene. Right: polypropene

The polypropene fibers are not as porous as cellulose fibers, and there are no OH groups

that can attract water. The result is a material that does not bind as much water as cotton.


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FUNCTIONAL MATERIALS

LAB INSTRUCTIONS

When you exercise, your body produces sweat. If your clothes become wet from the sweat,

and retain it on your body, they become heavy and your skin becomes cold. Nowadays,

many new textile materials emerge, especially suitable for sports activities. The goal is to be

able to exercise without sweat remaining on your body, keeping the skin dry. Lets see how a

few materials differ!

You need:

Some t-shirts made from various materials, e.g. cotton, polyester/cotton, wool and afunctional t-shirt. Let the students bring their own sports clothes!

A large container for water En vg.

Procedure:

Draw a table that you can fill out with data from the experiments. Fill a container with water.

Measure the weight of each t-shirt before wetting it. Soak the t-shirt in water and squeeze

the excess water out of it. Measure its weight again. Can you feel the difference? Can you

measure a difference in weight? How many percent does it increase?

Material Weight

(before water bath)

Weight

(after water bath)

Increase in percent

Things to discuss:

Which material is most accepts most water? Which material do you think is best suited for

wearing closest to your body on a day skiing in the mountain?


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MAKING GOLD

TEACHER NOTES

For whom: Ages 10-15

Many people like gold! The problem is that gold is expensive. In the old days, alchemists

tried to make gold out of cheaper metals. This was called transmutation. They all failed!

Problemet r att guld r dyrt. De gamla alkemisterna frskte i flera rhundraden framstlla

guld frn billigare metaller. Detta kallade man fr transmutation. Alla misslyckades!

In this experiment, we will try to make gold from copper. This is how it works:

When you put a piece of copper into a NaOH/Zinc bath, zinc will stick to the copper surface.

This think zinc layer looks like silver. If you scratch the silver surface, you can see that

there is copper beneath it.

When the piece of copper, covered in zinc, is heated, zinc and copper melt together, forming

brass. Such blends of two metals are called alloys. Alloys are used to change the properties

of the pure metals. Brass has a melting point of 900-940 degrees Celsius, depending on the

proportions of the two metals. This is why it is important not to heat the sample too much,making the brass melt.

Rusting of iron is a well-known phenomenon. By mixing chromium into the iron, rusting can

be prevented. When the amount of chromium exceeds 12%, the chromium on the surface

will oxidize and form a very thing protective layer that protects the iron from rusting.

Some other common alloys:

Steel: An alloy of iron and carbon. Used in e.g. car bodies.

Nickel silver: Also called nickel brass. An alloy of copper, zinc and nickel. A common mixture

is 54 - 67% copper, 22 - 29% zinc och 9 - 20% nickel.

Bronze: Various copper alloys. The most common one is a mix of copper and tin. By varying

the ration of copper and tin, as well as manufacturing method. The material can have very

different properties, to be used for example in church bells and canons.


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MAKING GOLD

LAB INSTRUCTIONS

You need:

Beaker that can hold 100 ml water Heating plate Pieces of copper Sodium hydroxide (NaOH) Zinc powder Gas burner Tweezers

Note this!!!

NaOH is very corrosive. Anyone making the experiment should wear protective goggles,

and a lab coat or an apron. If sodium hydroxide makes contact with your skin, rinse with

soap and plenty of water.

For a successful experiment, the copper must be clean. Use steel wool or autosol chrome

cleaner. Wash the copper thoroughly with soap to make sure there is no fat on it.

Procedure:

1. Dissolve 4 g NaOH in 100 ml water while stirring (the solution will become warm)2. Add a teaspoon of zinc powder in the NaOH solution and heat it on the heating plate

until it almost boils.

3. Put a polished piece of copper into the NaOH/Zinc solution. After a while, you cansee a silver surface appear.

4.

Use tweezers to pick up the copper piece and rinse it with water.5. Heat the copper piece with the gas burner. When warm enough, the color will

change from silver to gold. Put the gold in water to cool it down. Overheating will

make the gold color disappear.

Things to discuss:

Is it really silver and gold that is formed? Find out the density of copper, silver and gold. By

weighing the sample you can find out if it is really silver and gold what was the volume of

the copper piece?


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CREATING A SCENT

TEACHER NOTES

For whom: Ages 11-14

The characteristic scent from a perfume comes from the mixture of molecules in the

solution, each associated with a particular odor. Some of these odorants are also found in

fruits and are typically so-called esters. Some of these esters are simple molecules that,

when mixed in the right proportions, contribute to taste and smell. You can still identify

certain esters as characteristic of a particular fruit and use them as artificial flavor in for

example candy or as odorants in perfumes.

In a chemistry lab, it is relatively easy to make various esters. The simplest procedure is

called Fischer esterification. To make a Fischer esterification, you mix alcohol and a

carboxylic acid together with a small (catalytic) amount of strong acid, e.g. hydrochloric acid

or sulfuric acid, and heat the mixture.

During the course of the reaction, the alcohol and the acid will be joined together, while

water leaves (Fig 1).

Fig 1: Reaction between salicylic acid and methanol.

In this experiment we have made an ester on the carboxyl group in salicylic acid. If you

instead make an ester with acetic acid on the OH group, acetylsalicylic acid is formed,

which is the active compound in e.g. Aspirin (Fig 2).


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Fig 2: Reaction between salicylic acid and acetic acid.

Salicylic acid is named from the source of the compound, salix plants. The bark of such plants

has been long been used to make solutions to reduce fever and as painkillers. Already 400

B.C., Hippocrates wrote about a bitter-tasting powder, made from salix bark, with these

properties. Native Americans also knew how to use the salix bark.


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February Fashion Teaching Material