So, I've got five great projects for you to do in your own kitchen: Slime, Bouncy Balls, Crystal Ornaments, Dried Flowers and Flame Tests. (You can even use the Borax to clean up any messes you in pursuit of science!)
A quick note on safety: Though it is a natural substance it is important to wash your hands or wear gloves when using Borax. Clean up all residue well, with plenty of water. You may want to consider goggles as well.
1. Making Slime:
One of my kids favorite uses for Borax is to make slime. This gooey, messy concoction is always a hit. Luckily, it's very easy to do. And it teaches a lot about polymerization -- the Borax acts to link together chains in the glue, creating the rubbery, plastic-like slime.
Simply add 1/2 cup of water to 1/2 cup of white glue and mix well. The better you mix, the better your slime will be. Add a bit of food coloring or paint to color the mixture, if desired. Then make a solution of 1 teaspoon of Borax to 1 cup of water; mix until all of the borax is well dissolved. To create the slime, add the Borax solution to the glue mixture and stir.
The amount and vigor of stirring will affect the final slime -- ranging from oozy goo to a nearly Silly Putty consistency. You can also adjust how much of the Borax solution you add; more Borax means more polymerization and more of a rubbery concoction. If you want something really oozy, add less Borax.
This slime can be stored in a sealed bag or container for quite (two weeks) a while if it is kept cool or refrigerated. Be careful though; it can be tough to get out of rugs. To make the slime even more fun, try adding glow in the dark paint, using clear glue, or using glitter glue in the mix.
2. Making Bouncy Balls:
This relies on the same polymerization process as the slime, but uses corn starch as a binder. My kids always keep a real kick out of the changes the occur so quickly with this reaction.
The basis process is this: Make a Borax solution of 2 tablespoons warm water and 1/2 teaspoon Borax. Mix well and add coloring if you want. In a separate bowl, add 1 tablespoon of white glue to 1 tablespoon of cornstarch. Don't mix them just yet.
Now add 1/2 teaspoon of the Borax solution to the cornstarch bowl. Let this sit for 10-15 seconds to begin the reaction. Then start stirring. Once the mixture comes together as a sticky clump, you can take it into your hands, rolling it until you get a ball.
To be honest, this basic recipe doesn't really give you a great bouncy ball right off the bat, but the more you play with it, the more it sets up and the better it gets. The Borax bouncy ball provides a great opportunity for experimentation: adjust the concentration of Borax to water to adjust the polymerization. Or adjust the glue to cornstarch ratio to affect the density of the ball. There is certainly a science fair project in there, no doubt.
3. Making Crystal Shapes:
This one we love to do at Christmas time, because it makes pretty snowflakes, but it's fun to do any time of year, really.
You start by making a super-saturated solution of Borax. To do this, heat your water to boiling and it add to a glass jar (I like to use salsa jars or Mason jars). Add Borax by the tablespoon, stirring well after each addition. When you cannot dissolve any more Borax into the water, you've hit super-saturation. The water is actually holding more Borax than it can when cool! At this point you can add a bit of food coloring or liquid watercolor paint to tint the water (and therefore the crystals). If you plan to do many shapes, you can simple make a large batch of Borax solution and pour it into the jars.
Now take pipe cleaners and bend them into fun shapes. You can make swirls, hearts, stars, or, obviously, snowflakes. Use thread to create a hanger by tying it to the top of the shape. Place a pencil (or chopstick or bamboo skewer) across the top of the jar and hang the shapes into the Borax solution. Use a bit of tape to keep them attached (this is easier than tying them to the pencil). Make sure the shapes aren't touching the sides of the jar or each other.
Put the jars somewhere safe, where they won't be disturbed. You'll start to see crystals form as the solution cools, but it's best to give it 24 hours to let the crystals really grow. When they have, just pull the shapes out, dry them on a paper towel and enjoy!
4. Making Dried Flowers:
In the spring and summer, my kids love to save all the pretty blooms from our garden. This is actually a great field study, as we identify and preserve "weeds," leaves, and other wild plants as well. Once dried the flowers can be used to create any number of projects, including scrapbooks. However, the traditional method of drying flowers between the pages of a book has always yielded flat, discolored blooms. Using a powdered desiccant always gives better results, and that's where Borax comes in.
You can dry many flowers directly in Borax, but many experts recommend improvements. The most common mixture is equal parts Borax and cornmeal with 1-3 tablespoons of salt per quart of mixture. This provides the best combination of drying and color saving properties.
To dry your flowers, cut them fresh and trim the stems closely to the flower. Dry your flowers with a paper towel and remove any parts that are damaged or discolored. Add an inch of your mixture to a plastic dish. Place the flowers or foliage into the Borax mix, making sure they don't touch. Then gently cover with more the mixture until no parts of the plant can be seen. Cover the container and set aside for at least a week. Some layered blooms, like roses, may take up to two weeks to dry.
When the flowers are papery to the touch, simply shake off the Borax, or use an artist's paint brush to remove residue. Depending on how you plan to use the flowers, you may want to apply a sealant, such as a light coat of spray-on clear acrylic.
You can speed up the process by using a microwave, though results will vary. Simply prepare your flowers in the Borax mixture above, but don't cover. Place the container in the microwave with a small bowl of water. Cook on the medium to low power in 30 second intervals for up to 3 minutes, depending on the thickness of the plant. Don't rush it and don't "cook" your flowers on high! Set the container aside to cool for up to 24 hours before removing the flowers.
5. Make Colored Flames:
This is always fun. Burning various compounds that contain metals in a flame is a great way to demonstrate that various elements have their own unique properties. In this case, they create different colored flames. For this activity we're interested in the boron found in Borax.
You know that super-saturated Borax solution we made above? Time to use it again. Simply pour it into a small spray bottle, put on your goggles, fire up a propane torch or Bunsen burner (in a safe, clear space on a fire-proof surface), and spray the solution into the flame. You'll get a flame with a hint of green and yellow.
If that seems a bit messy and dangerous for you, you can create a wire loop with a "tail" that you push into a wooden dowel to deliver power or liquid into the flame on a gas stove burner or Bunsen burner. However, the resulting flame will be less dramatic and shorter lived.
You can also make solutions from other grocery and hardware store finds such as potassium chloride (sold as Nu Salt), boric acid (sold as a pest remedy), strontium chloride (sold as a fish tank additive), sodium chloride (table salt), copper sulfate (often found in root killer for plumbing) and magnesium (sold as pills or powder in the vitamin aisle).
For portable fun, soak items like dried pinecones in super saturated solutions, completely submerged, for several days then let them air dry. Use these in campfires to add colors to the flames. Again, not as dramatic as the spray method, but much easier to take on the go! Dipping the pinecones in wax and sprinkling the dried chemical over them before the wax dries also works, but must be handled carefully, for obvious reasons.
So have fun with some crafty science using Borax. I'd love to hear about your exploits!