CC U1: Pre-lab Tye Dye Lab

CC LL 1.__ Pre-lab Tye Dye Lab

Outline for your notebook

1. Purpose / Objective

2. Background

3. Safety

4. Materials (supplies)

5. Procedures

6. Observations &Data Table / List

7. Post lab Calculations (Set-up)

8. Post Lab questions
   
   

Multiple Choice

Do you have your notebook?

• Yes

• No... writing stuff down is optional

Purpose /Objective (Summarize in your NB)

The purpose of this lab

1. Practice writing a formal pre-lab including

   1. Taking notes on background info

   2. Writing / simplifiying procedures /methods

   3. Creating data tables /lists

2. Practice setting up calculations (see page 12 of your packet)

3. Reflect and improve pre-lab process for the future

Background Information about Tie Dying

​Chemistry behind Tye-Dye Fiber reactive dyes attach permanently to cellulose fibers or protein fibers using a covalent bond. These molecules carry a chromophore, which absorb varying spectrums of the light, allowing only certain spectrums to reflect. Each dye contains a different chromophore producing a different color. Since the dye permanently bonds to cellulose and proteins it will fix to all cotton clothes and skin! Covalent bonding is the one of the most basic and strongest types of chemical reactions. This reaction happens gradually over time depending on temperature and/or the pH level of the surrounding environment. The fixture pre-soak raises the pH level of the garment or fabric to approximately 10.5. Raising the pH level of the solution that the fabric or garment is soaked in raises the level of negative hydrogen ions in the dyeing environment. The chemical bonding process uses these ions in the reaction. Pre-soaking in Soda Ash fixer solution is what allows the fiber reactive dyes to work at room temperature. Otherwise this reaction would be nonspontaneous at room temperature and heat would have to be added to allow the reaction to take place. The dye is allowed to react in a desirable host environment for up to 24 hours. After this time, the bonding sites on the cellulose should be saturated with dye molecules. Excess dye molecules that have not bonded permanently are washed away using warm water and laundry detergent. The detergent is a surfactant so it also can bond chemically to the excess dye along with the water to allow it to wash away the left over dye.

​Background Information: Mixtures

​A heterogeneous mixture is a mixture in which the composition is not uniform throughout the mixture. Vegetable soup is a heterogeneous mixture. Any given spoonful of soup will contain varying amounts of the different vegetables and other components of the soup. A phase is any part of a sample that has a uniform composition and properties. By definition, a pure substance or a homogeneous mixture consists of a single phase. A heterogeneous mixture consists of two or more phases. When oil and water are combined, they do not mix evenly, but instead form two separate layers. Each of the layers is called a phase.​​

A homogeneous mixture is a mixture in which the composition is uniform throughout the mixture. The salt water described above is homogeneous because the dissolved salt is evenly distributed throughout the entire salt water sample. Often it is easy to confuse a homogeneous mixture with a pure substance because they are both uniform. The difference is that the composition of the substance is always the same. The amount of salt in the salt water can vary from one sample to another. All solutions would be considered homogeneous because the dissolved material is present in the same amount throughout the solution.

One characteristic of mixtures is that they can be separated into their components. Since each part of the mixture has not reacted with another part of the mixture, the identities of the different materials is unchanged.!

Subject | Subject

Some text here about the topic of discussion

​Background Information: Acids and Bases

​Water is the main ingredient of many solutions. A solution is a mixture of two or more substances that has the same composition throughout. Some solutions are acids and some are bases. 

The concentration of hydronium ions (H₃O₊)in a solution is known as acidity. In pure water, the concentration of hydronium ions is very low; only about 1 in 10 million water molecules naturally breaks down to form a hydronium ion. As a result, pure water is essentially neutral. Acidity is measured on a scale called pH, as shown in Figure below. Pure water has a pH of 7, so the point of neutrality on the pH scale is 7.

Acids--->

Bases-->

Multiple Choice

Did you take notes on background information.

• Yes

• No

Procedures: Day 1​

Subject | Subject

Some text here about the topic of discussion

​The objective of day 1 is to soak your shirt in a solution of sodium carbonate (Na₂CO₃). 

​Note: some individuals are rather sensitive to the very basic sodium carbonate solution to be used; rubber gloves are recommended. Thoroughly soak your T-shirt in the solution of sodium carbonate for at least 10-15 minutes. This process removes “sizing” or fabric fillers and therefore helps open up the bonding sites on the cotton molecules (cellulose polymer chains) to give the dye molecules a place to bond.

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Before placing your shirt in the sodium carbonate solution, record the mass of your shirt. While your shirt is soaking, collect approximately 50 ml of the sodium carbonate solution. Use your sample to determine the density of the sodium carbonate solution.

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Take the T-shirts out of the sodium carbonate solution and wring them out thoroughly. Record the mass of your shirt. Place them in the colored storage bin until Day 2. Clean up your lab area. Determine the mass of fixer that is currently soaked into your shirt. Using your mass and the density (use density as a conversion factor), determine the volume of fixer currently located in your shirt. 

​You may also look up your own design but advice from the past- keep it simple.

Procedures: Day 2​

Subject | Subject

Some text here about the topic of discussion

​Your shirt will still have remnants of the soda ash solution that can irritate the skin; gloves/aprons are advised.

Soak your shirt in a bucket of water and wring out. After everyone in your group soaked & wrung out their shirt. Fold and wrap your T-shirt in any of a number of ways that you researched. 

Note: If your shirt comes in contact with the lab stations or the tables it will be permanently stained. ​

Use rubber bands for any spiral patterns. Take the tied shirt into the lab, and place on to a metal grate over a plastic tray and begin dyeing.

You will be given a plastic cup and 3 large pipets to move the dye you need from the supply table to your shirt. Do not move the dye cups. You may need to rinse your pipets or cups. The dye can go down the drain with excess water. Use the pipets to squeeze out the desired dyes in the desired patterns on the T-shirt.

​<--

Yours to move

<--​

Procedures: Day 2​ continued

Subject | Subject

Some text here about the topic of discussion

Also, be aware that mixing will occur where the dyes come in contact with each other. These dyes are known as “fiber-active” dyes; that means they actually form a chemical bond with the cotton molecules, and are therefore essentially impossible to wash out. Double or triple bag your dye-soaked T-shirt in plastic bags and leave it to set for 24 hours. This gives the dye time to bond to the fabric, and as the water evaporates, it concentrates the dye to give richer colors. 

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Clean-up:

• Cups and pipets can go in the trash. Extra dye in your cup can go down the drain with excess water.

• All lab stations need to be wiped down and folding stations put at the front of the room.

• Any spills / drips must be cleaned up right away​

Procedures: Day 3

Subject | Subject

Some text here about the topic of discussion

​The next day, place your T-shirt in a grocery bag and take it home. When you’re ready, remove the rubber bands, open the shirt up (say “Ooooo” or “Ahhhhh”) and place it in a large bucket of water or rinse with a garden hose. Rinse it a few times, wring it out, then continue to rinse it with fresh, clean water until the rinse water comes out dilute enough so that you can see your hand through about 5- 6 cm (2 in) of the water. This rinse water is safe to dump on the grass. Wring out the T-shirt one final time, then wash it in the washing machine by itself.  Dry it (by machine on hot setting). Note: Some dryers have trouble drying just one item, so if you have a bunch of rags or clothes that you don’t care about, throw them in there too. 

Multiple Choice

Did you take notes on the procedures.

• Yes

• No

Data and Calculations

Subject | Subject

Either write the questions out or answer in complete sentences.

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1. Create a data table of the data collected in this lab. 

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2. Show your calculation for the density of the dye fixer.

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3. Determine the mass of dye fixer that is in your shirt as you initially hung it to dry.

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4. Using your mass (Problem #3) and the density (Problem #2) (use density as a conversion factor), determine the volume of fixer currently located in your shirt.

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Multiple Choice

What units are used to measure Density?

• cm³/g

• g

• g/cm³

• cm³

Multiple Choice

The equation for calculating density is?

• density = volume/mass

• density = mass/volume

• density = mass x volume

• density = mass + volume

Multiple Choice

What is the minimum time we need to let the dye soak in for?

• 6 hours

• 12 hours

• 24 hours

• 72 hours

Post Lab questions

Subject | Subject

Either write the questions out or answer in complete sentences.

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1. Reflect upon the pre-lab process

   1. What part of your pre-lab was the most organized/effective

   2. How could you have done better on the pre-lab?

   3. What would you change for the next-time you need to do a pre-lab?

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