NANO AT HOME: An Experiment That You Can Try

PLEASE NOTE: The Center for Nano- and Molecular Science and Technology (CNM) at The University of Texas at Austin (UT-Austin) cannot guarantee the accuracy or the safety of these activities.  Some of these activities might pose safety hazards for young children, and all activities should be performed under the supervision of a responsible parent, teacher or adult. The CNM and UT-Austin do not assume any responsibility for these activities or their results.  If you have questions, corrections, or comments please do not hesitate to contact the CNM.

Magnetic borax and glue slime

Described by: Karen Dismang, Dylan Kemmerer, Beth Boudreau, Mark Andrews, Dean Campbell

Making slime is a fun at-home science experiment that can be made easily from white glue and borax – items easily found at stores. You can add a variety of items to the slime to change its properties.  For example food coloring and glitter changes the appearance of the slime. This experiment focuses on the addition of magnetic iron oxide to the slime to make it responsive to magnetic fields, which allows you to move the slime around with a magnet. Adding iron oxide will also cause your slime to turn black.

This activity is similar to the use of magnetorheological fluids and ferrofluids: liquids containing magnetic particles that tend to flow to areas of strongest magnetic fields. (See: http://www.cnm.utexas.edu/magnetorheological-fluid/) for further description of magnetorheological fluids and ferrofluids.)


Supplies Needed

water
white school glue
borax
2 small plastic containers
magnetic iron oxide powder
plastic ziploc bags
stir stick
disposable gloves
Febreeze or  Lysol (optional)

Safety Considerations

Borax is not intended for consumption and make sure to wash your hands thoroughly after handling the slime. The slime may develop mold in a few days so you will need to dispose of the slime. Adding a few drops of Lysol or Febreeze might help with the life of the slime. You can store the slime in a ziploc bag or back into the plastic container that you mixed it in. Make sure that the container or the bag is air tight.  CAUTION: Strong magnets can pinch flesh and should also never be swallowed.

Procedure

In one of the plastic containers, add 50 mL of water (about 2 ounces) with an equal portion of school glue, and then add 4 g of the magnetic iron oxide.  This was 1 teaspoon for the iron oxide when we used “black iron oxide” purchased from a pottery supplier. This powder is used to color ceramic glazes for pottery and is composed of magnetite (Fe3O4). Caution: Fine powders can be a challenge to clean up! Covering your table or other work surface with newspaper before you begin is highly recommended.

Mix the components thoroughly with a stir stick. In another plastic container combine 1 g of borax (1/2 teaspoon) with 50 mL of water (about 2 ounces) and mix well until the borax is completely dissolved.

Pour the borax solution into the glue mixture and mix together.  The white glue is water and polymer chains of polyvinyl acetate.  Addition of borax cross-links the chains together, turning the sticky liquid into a slippery, somewhat solid-like mass. The new mixture will become very thick and hard to stir; let it set for 5 to 10 minutes. If the water is still not absorbed, you can knead it in your hands till all the water is incorporated. Your slime is complete!

Have fun pulling and stretching the slime! If you would like to see your slime move in a magnetic field, wrap a strong magnet with cellophane (plastic wrap) to protect the magnet.  The magnet must have a bit of magnetic field strength, say, enough to lift a full soup can.  Many ceramic ferrite magnets will work; “neodymium” magnets should will likely work even better.  CAUTION: Strong magnets can pinch flesh and should also never be swallowed. Place the magnet on aluminum foil, cellophane, wax paper, cookie sheet, or something else that will not absorb the water out of the slime. Place the slime about 1 cm (0.5 in) away from the magnet and watch; the slime will start moving towards the magnet and crawling over it as the particles are attracted to the magnet. The images below are a sequence of the slime crawling over a 15 to 20 minute period from left to right. The white trapezoid shape is a strong magnet. The slime and magnet were placed on aluminum foil.

Reference

Helmestine, A.M. Step-By Step Slime Instructions. About.com/Chemistry. 6/25/2014. http://chemistry.about.com/od/chemistryactivities/ss/slimerecipe.htm.