This slime recipe is based on the classic polyvinyl alcohol (PVA) formula with sodium tetraborate as the cross-linking agent. Doesn't that sound impressive? What makes our slime formulation unlike anything else on the market is the addition of our stabilizing agents that help to reduce the growth of bacteria while preserving the stretchy, stringy, gooey properties of slime that everyone loves. Turn this ever popular science activity into a real learning experience that is filled with real fun.
What does it teach?Slime is a great way to introduce your class to the chemistry behind cross-linking solutions. The long-linking chains of molecules in the PVA are called polymers; the Borax solution acts as a cross-linking agent for these polymers and helps the chains connect. Slime solution is also a great illustration of what scientists call a “Non-Newtonian Fluid”… when you apply pressure it forms a sort of solid and breaks. When you let it flow like a liquid it easily stretches. All of these science secrets are made even better with the addition of our special coloring agent that fluoresces under black light. When the energy from the black light “excites” the fluorescent dye, you end up with a brightly glowing, very exciting, ooey, gooey experiment! (For the full glowing effect, you will need to purchase a large black light.)
Bubbles are beautiful, fun, and fascinating, but do you know what they are and how they work? Here's a look at the science behind bubbles. What Is a Bubble? A bubble is a thin film of soapy water. Most of the bubbles that you see are filled with air, but you can make a bubble using other gases, such as carbon dioxide. The film that makes the bubble has three layers. A thin layer of water is sandwiched between two layers of soap molecules. Each soap molecule is oriented so that its polar (hydrophilic) head faces the water, while its hydrophobic hydrocarbon tail extends away from the water layer. No matter what shape a bubble has initially, it will try to become a sphere. The sphere is the shape that minimizes the surface area of the structure, which makes it the shape that requires the least energy to achieve. What Happens When Bubbles Meet? When bubbles stack, do they remain spheres? No, when two bubbles meet, they will merge walls to minimize their surface area. If bubbles that are the same size meet, then the wall that separates them will be flat. If bubbles that are different sizes meet, then the smaller bubble will bulge into the large bubble. Bubbles meet to form walls at an angle of 120°. If enough bubbles meet, the cells will form hexagons. You can see observe this structure by making prints of bubbles or by blowing bubbles between two clear plates. Bubble Solutions Though soap bubbles are traditionally made from (you guessed it) soap, most bubble solutions consist of detergent in water. Glycerin often is added as an ingredient. Detergents form bubbles in much the same way as soap, but detergents will form bubbles even in tap water, which contains ions that could prevent soap bubble formation. Soap contains a carboxylate group that reacts with calcium and magnesium ions, while detergents lack that functional group. Glycerin, C3H5(OH)3, extends the life of a bubble by forming weaking hydrogen bonds with water, slowing down its evaporation.
Learning about the science of things that glows requires an understanding of two important terms - fluorescence and phosphorescence. It's also important to note that not all zinc sulfide glows, but luminous zinc sulfide does glow!
Fluorescence - This type of luminescence occurs when some form of radiation, such as light, causes an object to glow. For example, fluorescent papers and poster boards glow in the daylight. They may seem to glow even brighter under black light (ultraviolet), but in either case, as soon as the light is removed, the glow stops. Fluorescent things do not glow in the dark all by themselves – they require some other form of energy such as ultraviolet light to “excite” them.
Phosphorescence - Phosphorescence is just like fluorescence, except that the glow continues even after the light used to excite it is removed. “Glow in the dark” toys phosphoresce brightly in total darkness after being “charged” or excited by ordinary white or ultraviolet light. Glow Powder works by absorbing surrounding light energy and then releases that energy when the lights go out. It's called a phosphorescent It's the perfect way to get your students excited about energy... and a great way to celebrate Halloween! Just add glow powder to almost any of our favorite products and you'll have an eerie new take on your favorite experiments!
So, how does zinc sulfide work? Imagine that an atom looks something like our solar system. The sun would be the nucleus consisting of positive charges called protons and neutral charges called neutrons. The planets spinning around the sun would be similar to the electrons of an atom in orbits around the nucleus.
When the electrons in the atoms of special molecules like zinc sulfide become excited, they move farther away from the nucleus -- into higher or more distant orbits. In order to become excited, the electrons must take on energy. In this case, light provided the required energy to cause the electrons to move to a higher energy level. It’s as if Earth were to move farther away from the sun into the orbit of Mars or Jupiter.
The electrons will remain in the excited state as long as they receive light to energize them. But, when the light used as an exciter is removed, the electrons will slowly return to their original lower orbits. As they do so, they give up the energy that excited them in the form of light.