Many food, hygiene and pharmacy products contain cellulose products

Examine 5 food packets and 5 other products to see if any of the following additives are in them

Food Additives ANZ Standards Numbers
Name of additive	Number - ANZ Standard	Type or use	Product which contains the food additive
Microcrystalline Cellulose	460
Methyl cellulose	461	thickener, stabilizer, emulsifier
Hydroxypropyl methylcellulose	464
Sodium carboxymethylcellulose	466

 

• Explain the advantages of using these additives.
• Conduct a 1-hour supermarket survey
  • List 20 foods with these additives. Include the percentage by weight in each food.
  • Make a bar graph from your data.
  • Which food was most surprising in containing additives?
• Survey five different kinds of eyedrops. Report on your results.

Wallpaper adhesives - information site, from Wall Paper Installer

Choosing the wallpaper adhesive -information site, from DIYnot.com

Material Safety Data Sheet: for POLYPAPER PASTE -(pdf113.1kB)

Wall paper paste - recipe for old starch based wallpaper paste, from Care2MakeaDiffernce

Activity

Design and carry out some tests to compare the strength of the adhesive bond of cellulose paste and starch paste (either commercial or home made, using wallpaper (many shops have sample books) or heavy brown paper as a substitute. Remember that wallpaper is hung on a vertical surface.

Get real: Develop toothpaste formulas - see page 3 of You and Your BIG Mouth, from BioSTARS, Biology for Students, Teachers, and Researchers(pdf 359.9kB)

Teaching Notes: You and Your Big Mouth - from BioSTARS, Biology for Students, Teachers, and Researchers

Activity

Compare the ingredients with those listed in the Australian Prescriber: Contents of toothpaste - safety implications

What is missing on the worksheet?

Activity: Lost in the wilderness

How would you clean your teeth if you hand neither brush nor toothpaste?

Toothpaste History

Toothpaste History - From ToothpasteWorld/Wisdom

Toothpaste - A Brief History - from SaveYourSmile

Contents of toothpaste - safety implications - from From the Australian Prescriber

Ingredients - toothpaste - from Science Toys

Activity

Make your own haig gel using ethanol or isopropanol as a solvent for methylcellulose. Compare 2% and 4% weight to volume.

Which would make a better hair gel?

Examine the labels of several brands of hair gel and find the most common ingredients.

Activity

Wear disposable plastic glove and goggles for this activity.

Mix fertilizer powder and Plaster of Paris in varying amounts to determine how much plaster is needed to hold everything together. Be sparing with the water.

Make up the mixture in a plastic cup then roll it out into thin cylinders on plastic sheeting. Use a disposable plastic knife to cut into pieces that will roll into 2 mm diameter pellets and leave to dry.

Make a list of ingredients

Calculate the amounts you will need

Make the pellets

When the pellets are dry, divide into four equal quantities. Set one quarter aside as a control.

Make three solutions of methyl cellulose dissolved in denatured alcohol of varying strengths e.g. 1%, 2%, 3%.

Paint the other three quarters with the methyl cellulose/alcohol solutions. Leave to dry.

Prepare a tray of damp sand (takeaway containers) and divide the surface into four.

Sprinkle your pellets into the quarters, and see how long they take to break down.

Report on your investigations.

When finished, place the remaining pellets in the school garden or on the grass just before rain.

Discussion

Would it be better to use larger or smaller pellets?

Examine some commercial slow release fertilizer pellets

Take a sample of 20 pellets. Find the average diameter.

Some manufacturers use dilute PVA (White glue), about 1-2% and a similar mix is used by makers of seed bells for pet birds.

How to make your own slow release fertilizer cakes - from Dale Cochoy

Read the passage and discuss whether Dale could have used some methylcellulose.

Feritilisers - from Fertool(pdf 76.6kB)

How do controlled release fertilizers and slow release fertilisers differ?

Slow-Release Fertilizers - from Virginia Tech

Food dye electrophoresis - from Queensland Museum, uses agar as gel(pdf 186.6kB)

DESKTOP ELECTROPHORESIS LAB - MOVING MOLECULES - from Access Excellence

Rainbow Eletrophoresis - from Access Excellence

Electrophoresis Base Unit - developed for schools, from National Centre for Biotechnology Education, UK

Microscopy

Collect labelled samples of paper e.g. copy paper, brown paper, toilet paper, tissues, drawing paper

examine torn edges with a microscope

Repeat after mounting the samples in water. Does water affect the samples?

Compare paper samples mounted in very dilute iodine solution, which gives a violet colour if starch is present.

Examine paper samples mounted in dilute acetic or citric acid. If there is carbonate present, there will be bubbles of carbon dioxide gas forming. Some papers are treated with carbonate to make them less acid.

Record your observations in a table for your results.

Sized paper

Manufacturers add size (e.g. starch) to make the paper more absorbent and easier to write on. Many modern papers have methyl cellulose sizes which do not show a violet colour with iodine solution.

Investigating the effect of sizing paper

Dip some sheets of newsprint (butcher’s) paper in 1% solutions of water, cooked starch and methylcellulose and let them dry.

Cut up into similar size strips.

Use a water based fibre tip pen or a fountain pen to write some UUUU’s or OOOOO’s on strips of each kind of paper.

Use a hand lens to examine the writing when it has dried.

Why use the water?

Which size gives the clearest writing?

Strengthened paper

Dip sheets of newsprint, paper towels or serviettes and tissues into 2% methyl cellulose solution and allow to dry.

Cut into equal sized pieces. Mark the pieces with a pencil eg A, B,C.

Design a test to compare the dry strength of strips of coated and uncoated papers i.e. the resistance to tearing when dry

Design a test to compare the wet strength of strips of coated and uncoated papers i.e. the resistance to tearing when wet

Does methyl cellulose strengthen paper?

© 1997 - 2010 UniServe Science

Page Maintained By: uniserve@usyd.edu.au
Last Update: Monday, 09-Nov-2009 15:17:14 EST
URL: http://science.uniserve.edu.au /school/curric/stage4_5/fibres/prac_ideas5.html