Count on Chemistry Presented by the MathScience Innovation Center Written by Theresa Meade

What is a polymer? It is a long, long molecule! It is a long, long molecule! Polymers can occur in nature or they can be made by humans. Can you guess which of these are polymers? Polymers can occur in nature or they can be made by humans. Can you guess which of these are polymers?

What is a polymer? It is a long, long molecule! It is a long, long molecule! Polymers can occur in nature or they can be made by humans. Polymers can occur in nature or they can be made by humans. This is a small molecule. It is not a polymer.

What kind of math is here? Long chains mean adding the same thing over and over. Long chains mean adding the same thing over and over. How does that relate to math? How does that relate to math? Long chains can be hard to analyze. Sometimes it’s easier to look at the parts. Long chains can be hard to analyze. Sometimes it’s easier to look at the parts. How does that relate to math? How does that relate to math?

Today we will… Look at large pieces Look at large pieces Look at the smaller pieces “inside” Look at the smaller pieces “inside” Think about changes Think about changes And have fun with math and science! And have fun with math and science!

What is a polymer? A polymer has a repeating pattern inside it. That pattern is made of a few atoms joined together to make a monomer. A polymer has a repeating pattern inside it. That pattern is made of a few atoms joined together to make a monomer. Many, many monomers join together to form polymers. The number of parts determines what the whole looks like! Ethane, butane, paraffin, and polyethylene Many, many monomers join together to form polymers. The number of parts determines what the whole looks like! Ethane, butane, paraffin, and polyethylene

Ethane First discovered in 1834 First discovered in 1834 A component of natural gas A component of natural gas

Butane Liquid form Liquid form Found in LPG bottles used in gas grills Found in LPG bottles used in gas grills

Paraffin Waxy solid Waxy solid Used in candles and has a low melting point Used in candles and has a low melting point

Polyethylene Solid Solid This is everyday plastic—milk jugs, detergent bottles, or any plastic This is everyday plastic—milk jugs, detergent bottles, or any plastic

Thinking… How can we create a model for the parts of a whole? How can we create a model for the parts of a whole? We will start with some basic materials. Get ready! We will start with some basic materials. Get ready!

Let’s look at a model Label one end of a strip of paper 0. Label one end of a strip of paper 0. Fold, then open. Fold, then open. What should we label the fold line? What should we label the fold line? What should we label the other end? What should we label the other end? 1

Let’s look at a model 10 Let’s look at another strip of paper. Let’s look at another strip of paper. Label one end with 0 again. Label one end with 0 again. Fold. Fold. Without unfolding, fold the paper one more time. Without unfolding, fold the paper one more time. Unfold your strip. Unfold your strip. How many pieces all together? How many pieces all together?

Let’s look at a model 10 Do you remember the steps? What do we do first? Do you remember the steps? What do we do first? Fold your paper. Without out opening, fold it again. Now fold one more time. Fold your paper. Without out opening, fold it again. Now fold one more time. How many pieces do you predict there will be? How many pieces do you predict there will be? What should we label the end? What should we label the end? How many parts all together? How many parts all together?

Let’s look at a model 1 0 Let’s make one more fraction strip. Let’s make one more fraction strip. Remember the process? Remember the process? Label the end with 0. Fold the strip. This time fold it a total of 4 times without opening. Label the end with 0. Fold the strip. This time fold it a total of 4 times without opening. How many pieces do you predict there will be? How many pieces do you predict there will be? Open and look! Open and look!

Guided Practice Don’t answer any of the questions yet! We’ll do these together in just a moment! Don’t answer any of the questions yet! We’ll do these together in just a moment! So which one is larger, or ? So which one is larger, or ? How do you know? How do you know?

Guided Practice What are equivalent fractions? What are equivalent fractions? Yes! They are two different ways to name the same amount! Yes! They are two different ways to name the same amount! Write some of the equivalent fractions we talked about on the lines in Part 1 of your Data Sheet. Write some of the equivalent fractions we talked about on the lines in Part 1 of your Data Sheet. What are some of the numbers you wrote? What are some of the numbers you wrote?

Guided Practice What happens when you add + ? What happens when you add + ? 10

Guided Practice - = 10

Guided Practice Work with a partner to figure out problems 3 and 4. Work with a partner to figure out problems 3 and 4.

Guided Practice I have 10 I want to add

Guided Practice I have I want to add

Guided Practice + = 1 ? + 1 = 1 - = ? ? ? ? ?

Saving your work Use a glue stick to save all of your fraction strips. Use a glue stick to save all of your fraction strips.

What if… …you didn’t have fraction bars? …you didn’t have fraction bars? Number lines can help you think about fractions! Number lines can help you think about fractions!

Number lines When you add fractions with the same denominator, draw one line. Find your starting point and decide how many “hops” to take to get an answer. 10 +

Number Lines + = Step 1: Draw two number lines since you are adding numbers with two different denominators.

Number Lines + = Step 2: Decide how to mark your number lines.

Number Lines + = Step 3: Find an equivalent fraction to use for a starting point.

Number Lines + = Step 4: Add!

Time to work with your partner You and a neighbor will work together to complete the rest of your data sheet. You and a neighbor will work together to complete the rest of your data sheet. There is a front and a back, but don’t worry if you don’t have time to finish! There is a front and a back, but don’t worry if you don’t have time to finish! Remember to work like a mathematician—be accurate, take your time, and talk to your partner. Remember to work like a mathematician—be accurate, take your time, and talk to your partner.

Answers? How did you do? How did you do?

Why look at parts of the whole? Many scientists do exactly what you did! Many scientists do exactly what you did! Think about genetics! We look at part of the DNA strand. Think about genetics! We look at part of the DNA strand. Think about creating synthetic vitamins. We look at part of the molecule and recreate it! Think about creating synthetic vitamins. We look at part of the molecule and recreate it! Think about making better plants and cross- breeding to get new varieties of roses. Think about making better plants and cross- breeding to get new varieties of roses. It’s all about the parts! It’s all about the parts!

Now let’s look at polymers again What do those long strings of monomers do? What do those long strings of monomers do? They have some very interesting properties! They have some very interesting properties! It’s time for a demonstration! It’s time for a demonstration!

Did you enjoy polymers? Chemical engineering uses math and the art of putting things together to create and discover new compounds. Chemical engineering uses math and the art of putting things together to create and discover new compounds.

Thank you!