7th grade science project ideas


Just How "Permanent" are "Permanent" Markers?

If you want your markings to last forever, you had better check into this project to see just what happens to the so-called permanent markers.

Permanent markers are marker pens used to create permanent writing on an object. Generally the liquid is water resistant, contains a solvent such as xylene, toluene, or alcohol and is capable of writing on a variety of surfaces from paper to metal to stone. They come in a variety of tip sizes from ultra fine to wide, shapes such as chisel point, bullet tip, and wide bristle, and colors such as metallic, non metallic, or ultraviolet reactive. These markers give off volatile organic compounds, which in some cases are toxic. Permanent inks contain three main ingredients: colorant, carrier, and resin. A colorant, usually dyes or pigments, is what gives markers their permanence, and, of course, their color. A dye is usually a coloring material dissolved in water or a solvent, making it a water soluble dye.

Solvents are used as the carrier in permanent markers. Before the nineties, most markers were made out of foul smelling hydrocarbon organic chemicals, like xylene or toluene. Although these chemicals provide a desirable permanency, they are highly toxic. There has also been concern among users that they may damage plastic surfaces such as the back of a CD or DVD. Today, xylene may be used in some markers but most markers are now replaced with an alcohol solvent. Alcohol, such as ethanol or isopropanol, is more environmentally friendly and even smells better. It also evaporates quickly, allowing permanent markers to dry faster.

The last component, resin, is a polymer that promotes adhesion. This also adds to the permanence of markers. The resin sticks like glue to most of the surfaces the marker is written on causing the pigment to attach to surfaces.

These markers are generally not truly permanent as, on most surfaces, they do not stain but form a surface layer that can be removed by high pressure cleaning or paint thinning solvents such as acetone, and they will eventually wear away over time. Some markers are designed to be long lasting, for instance by having two inks, one specialized to resist solvents, and one specialized not to fade. These are primarily used in graffiti and can be available in refillable form. A permanent marker can also be removed using a dry erase marker on certain surfaces such as a whiteboard as it contains acetone.

You will require certain materials to do this project including several different brands of permanent markers, carpet, wood, plastic, T-shirt, Mr. Clean Magic Eraser, rubbing alcohol, hair spray, white toothpaste, bleach, water, rubber gloves, scrub brush, notebook and pencil.

This project is to see just how permanent permanent markers really are. To do this project you will need at least three different brands of permanent markers, several different materials to test the markers such as plastic, paper and fabric, and a few different solvents to try and remove the marker such as water, rubbing alcohol, and vinegar. You may wish to divide a page of your notebook into four squares. Each square could be headed clothing, wood, plastic, and carpet. As you test each of the cleaning agents you use to remove the permanent markings from these different surfaces, you will log in your results. Make certain that you indicate which brand of marker you are using. You may need several different sheets of paper with these indications for each different marker and each different cleaning material.

You will of course hypothesize which solutions will remove which markings on which surfaces. You have three variables at work here so get yourself organized.

Using permanent marker Brand A, make a stain on all four surfaces.

Then try to clean the surfaces and remove the marker using different cleansers such as nail polish remover, Mr. Clean Magic Eraser, rubbing alcohol, white toothpaste, and finally a bleach water mixture. You need to wear some rubber gloves to protect your hands from any chemicals.

Log in all of your results on the page with the four squares. If you use more than four different surfaces, then you will need five squares or six squares or whatever you need. Were any of the stains removed? How were they removed? Did some cleaning agents seem to work well on one surface and not another? Why do you think that is? Compare your conclusions with your hypothesis.

There are several different methods that you can use to make your markings. You may wish to draw a thick black line all the way across each testing surface; the plastic, the paper, and the fabric, and then break the line into four sections by drawing three lines the opposite way on the paper of the thick line, and then let it dry for about 20 minutes.

After it is dry, apply a few drops of water to one section on the plastic, a few drops of rubbing alcohol to another, vinegar to another and so on. Repeat this process for the paper and fabric. Did any of the solvents take the permanent marker off?

CLICK HERE for complete details on this project.



seventh grade science fair project ideas


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