Magnetic Slime

This little project feels like something out of a sci-fi, which perhaps is why I love it so much. Add some magnetite powder to your next batch of slime, get a strong rare earth magnet, and your kids (or you) will have a blast making zombie worms and magnet eating monsters- straight out of the movies!

Safety: Do not ingest any part of this project. Do not use any of the materials around small children or children who put things in their mouth. Too much iron is poisonous and it should not be ingested in this form. Rare earth magnets are very strong and can pinch fingers, be careful when using them. Magnets should never be left around small children who could ingest them. Do not use magnets near electronics or credit cards. The magnet in the video has a pulling force of 48 lbs. This was more than sufficient. If you are doing this with kids, do not use a more powerful magnet and only use one magnet at a time to avoid pinched fingers.

Materials

Procedure

  1. In a bowl or cup, dissolve the 1/8 tsp borax in 1/4 cup hot water. Set aside.
  2. To a different bowl, add 1/4 cup glue, 1/4 cup water, and 3 tbs iron oxide powder. Mix well. (Note: The powder will stain skin, so try not touch the iron oxide with your hands at this point, wait until the borax solution is mixed it. If you do get it on your hands, dish soap washes most of it off.)
  3. Slowly add the borax solution to the glue mixture and mix well.
  4. Take the slime out and knead with your hands till it is smooth. If it feels sticky, dip it in the extra liquid in the bowl and knead again.
  5. Start playing with the slime and magnet!

The Science Behind Slime

The glue contains a long molecule called polyvinyl alcohol (PVA). It is a polymer, which is a molecule that contains repeats of a subunit molecule (for example, “A” is a subunit and “AAAAAAAAAAAAAAA” is a polymer of A). Borax (sodium tetraborate) is a small molecule that can stick to parts of the PVA through hydrogen bonds. This means one side of the borate molecule can stick to one strand of PVA, while the other side of the borate can also stick to a different strand of PVA, creating a bridge between the two PVA strands. This is called crosslinking.

Having many crosslinking sites usually makes a polymer more rigid, but the interesting thing about borate/PVA crosslinking is that the bond is transient, meaning it can easily break and reform somewhere else. This causes the slime to act kind of like a liquid and kind of like a solid. If given time, the PVA can ‘flow’ as gravity pulls and breaks the borate/PVA crosslinks. It acts like a slime instead of a true liquid because as the PVA molecules pass by more borate, they can momentarily bond to borate and another strand of PVA, slowing down the flow. If you pull the slime fast, you break all those bonds quickly, allowing the slime to act like a solid momentarily.

The Science Behind Magnetic Slime

The iron oxide powder in the link above is magnetite, which is a natural mineral made of iron and oxygen. Like many iron-containing compounds, it is attracted to a magnet.

The iron oxide particles in the powder will become suspended in your slime matrix. As the particles are attracted to the magnet, they will pull the slime matrix with them, causing a whole section of the slime to move with it. This makes for some really cool effects!


If you’re looking for a project to use some of the leftover ion oxide powder, try our DIY Magnetic Shapes!

Birthday Cloud Dough

Get ready for some soft, colorful, messy, moldable fun! Sprinkles plus cloud dough make for a festive activity, full of problem solving, sensory stimulation, basic engineering, and more!

Materials

  • Flour
  • Oil (any taste-safe liquid oil will do, like canola or rice bran oil)
  • Sprinkles
  • Plastic bin or cookie sheet
  • Various toys
    • Molding cups
    • Candles
    • Spoons
    • Ice cream scoop

Method

  1. Mix 4 cups flour with 1/2 cup oil. Rake with a fork or fingers till well blended.
  2. Mix in 1/2 cup of sprinkles.
  3. Dump in a bin or cookie sheet and let them go at it!

This is quite messy and will probably get all over your kids clothes and the floor. Luckily, it sweeps up easily and comes right off in the washing machine.

Birthday cloud dough

Star Fruit, Caramboxin, and Neurotoxins

Sliced star fruit and the chemical structure of caramboxin.

I’ll preface this with “I still ate it,” but star fruit contains a deadly neurotoxin called caramboxin. 😱*clutches pearls*

Luckily, if you have normally functioning kidneys, caramboxin gets flushed out of your system and does absolutely no harm. In fact, my friend from Taiwan says they eat star fruit daily, and they’re all doing fine so, again, totally fine for most people to eat. However, if you have kidney disease, the toxin does not get removed and it can go on to interfere with your neurons.

Neurons pass messages around your body. Molecules called neurotransmitters are released from one neuron and passed to another in order to relay that message. The neurotransmitters fit snuggly into proteins called receptors on the next nerve. This is kind of like a lock and key. Once the receptor is “unlocked” by the neurotransmitter “key,” the nerve passes the message to another nerve, and so on. Caramboxin can “unlock” and stimulate some of these nerves by snuggling up to the receptor. Normally, turning on neurons is a very controlled process, so when caramboxin gets in there, it messes things up. Symptoms include mental confusion, vomiting, and seizures, and in some cases, coma and death.

Interestingly, an early symptom of caramboxin poisoning is intractable hiccups, so if that happens to you after eating star fruit, call the doctor and ask about some kidney labs!

This was my first star fruit ever! I don’t think I let it ripen enough, but it tasted like a wet tart apple. Should I wait longer next time based on that green color? No hiccups yet!😉

Source: Garcia-Cairasco et al 2013 https://doi.org/10.1002/anie.201305382

DIY Magnetic Shapes

I’m always trying to find ways to repurpose supplies I purchase for activities. We have a big bag of magnetite powder we use to make magnetic slime, but I haven’t thought of another use for it…until now! By mixing it with glue and baking soda, you can pipe (like frosting) any design you can think of, and it will stick to a magnet. This is perfect for magnet-on-a-pole fishing games. Read on to learn more!

Materials

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Method

Note: Magnetite powder (an iron oxide) is very messy and should not be touched with bare hands as it stains. Wash hands thoroughly after doing this. Older children may help with steps 3-6, but should always be supervised as any large amount of iron is dangerous to ingest. The dried shapes are safe to handle with bare hands, but the shapes and magnets should not be handled by children who put things in their mouth.

  1. In the ziplock bag, measure in a 1:1:1 ratio the magnetite powder, school glue, and baking soda. Since the first two ingredients are so messy, it is totally fine to just eye-ball the amounts. This is a very forgiving goop.
  2. Squeeze out the air and seal the ziplock bag.
  3. Mix the contents thoroughly by squeezing and mushing.
  4. Snip off a small lower corner of the bag and pipe designs onto wax paper like you would if you were decorating a cake. (Though these will not be incredibly fragile, you don’t want any shapes to have lines with less than ~1/4 inch thickness or they will break with typical child’s play.)
  5. Let dry for 24 hours.
  6. Paint the shapes with paint or nail polish.

Discussion

Magnetite is a natural mineral made of iron and oxygen. It is attracted to a magnet and in some cases can be magnetized to become a permanent magnet. Magnetism was discovered millennia ago by observing metal sticking to naturally magnetized magnetite, called lodestone. Though I haven’t been successful in magnetizing the shapes made by this project, it is possible to magnetize magnetite by placing it in a strong magnetic field (eg. very strong magnet or electromagnet).

The shapes you will make are called magnetically soft, in that they become temporary magnets when exposed to a magnetic field (i.e. other iron-containing things will become attracted to it when it, itself, is in a magnetic field), but if the magnet is removed, the shape becomes unmagnetized.

How to Play

  • Alphabet Fishing (learning letters): We tied a magnet to a wooden pole and went “fishing” for magnetic fish shapes and letters covered by dried rice in a plastic bin. You can use this activity to learn upper or lower case letters, or spelling a name.
  • Fishing for Compliments (learning to read): We made magnetic hearts and I wrote adjectives that complimented my daughter on the back of them (eg strong, smart, kind, etc). She fished for them in a tub of dried rice and black beans and sounded the words out as she found them.

As always, let us know if you’ve tried this on Instagram and Twitter @cara_florance. Tag us and include the hashtag #IBravedTheElements for a chance to be featured!

xoxo

Cara

Magic Color Changing Raised Salt Painting: A STEM Activity

This activity takes raised salt painting to a whole new level! In this twist, we use some secret ingredients that will make the special paint change color once it hits the salt!

The above picture was made entirely by my almost four year old. And even though this was the fourth picture she had made, the process was still as magical to her as the first time.

 

The secret to the color change is in the special paint. Instead of a true watercolor, we are using red cabbage juice! Red cabbage juice contains molecules called anthocyanins that change color when exposed to different pH levels. For more of the science involved, check out this post. The painting surface, which is usually just glue and salt in the classic activity, is actually different mixes of glue, salt, and safe household acids or bases in our version. You can create the picture beforehand for your child (like I did above in the mermaid video), or they can plan and create their own science art all by themselves (like the snowman further up).

Materials

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Method

Making Red Cabbage Juice

There are several ways to get juice from a red cabbage. All of these methods make quite a bit of juice. We freeze leftover juice in an ice cube tray, then save the cubes to melt for future projects.

  • Just juice some in a juicer (if you have one).
  • Add about a quarter of the cabbage to a blender and blend with about a cup of water (adding more or less depending on how much cabbage you have). Then strain the liquid.
  • Bring ~2 cups of water with chopped red cabbage to a boil, turn off heat and let sit till it’s cool. Strain the liquid.

Making the Salt Mixes

You can safely access three colors of the red cabbage juice with household solid chemicals: blue-green, purple, and pink. Prepare the mixes in a bowls or cups. Don’t forget to label them. Make as much as you need, or save some for later. The amount you make will depend on how much glue you need to cover, but the mermaids above took about 2 tbs of each.

  1. Acidic Mix (Pink): 1 part citric acid to 6 parts table salt
  2. Alkaline Mix (Blue green): 1 part baking soda to 3 parts table salt
  3. Neutral Mix (Purple): All table salt

Making Your Art

  1. Draw your design on the paper with a pencil.
  2. Decide which parts will be blue, pink, or purple.
  3. Using the glue, trace the drawing on just the lines that will be pink.
  4. Sprinkle the Acidic Mix onto the glue (with fingers or a spoon), then shake off the excess.
  5. Using the glue, trace the parts of the drawing that will be blue-green.
  6. Sprinkle the Alkaline Mix over the new glue, then shake off the excess.
  7. Using the glue, trace the parts of the drawing that will be purple.
  8. Sprinkle the Neutral Mix over the newest glue then shake off the excess.
  9. Let dry for about 30 min (This is optional. It will still work when the glue is wet, but you just have to be careful to not smoosh it with the paintbrush otherwise acid or base crystals that get stuck to the brush may change the color of your paint stock when you double dip.)
  10. Load a brush with red cabbage juice and touch it to the salt/glue lines. Keep dabbing until your whole painting changes color before your eyes!

If you try this, be sure to share your creations with us! Find us on Instagram and Twitter @cara_florance. Use the hashtag #IBravedTheElements and we might feature you!

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Diaper Snow: Sensory Science

Deep inside diapers lies an amazing molecule that can absorb hundreds of times its weight in water. It is called sodium polyacrylate and is an inert, skin-safe polymer that can provide loads of fun sensory play. Read on to learn what it is, where to get it, and what to do with it!

Materials and Methods

Sodium polyacrylate can be purchased as artificial snow (click here for to buy) or harvested from an unused diaper. To do the latter:

  1. Cut the top cloth-like layer of the diaper (the part that touches the baby) right down the middle width-wise.
  2. Fold it on the cut, cut side down and put it in a plastic tub.
  3. Shake it until tiny white specks gather at the bottom of the container.
  4. Remove the diaper.
  5. Add water (with food coloring if you want) a little at a time and watch as the water is quickly absorbed into the growing mass.
  6. For a lighter texture, add less water, for a slushy texture add more water.

Discussion

Polyacrylate, on the molecular level, is like a long string of negative charges. The sodium, which is positively charged, sits on these negative charges all along the string, which allows the polymer to coil and tangle up. When water is added, it displaces the sodium and nuzzles up with the negative charges. This causes the polymer strand to unravel, not only increasing the size of the gel, but also exposing more negatively charged sites so even more water can bind. This is why you get so much absorbent bang for your buck.

What to do with it?

  • Sensory Bins
    • Add cups and molds and make sand castle-like creations with the slush form (more water)
    • Add small world toys, like evergreen trees and arctic animals, to play with the lighter form (less water)
    • Initially make the snow without coloring, then give the kids squirt bottles with colored water to
  • Magic Tricks
    • Make water “disappear.” Put the dried sodium polyacrylate at the bottom of an opaque cup, show that it is “empty”, pour water in, then flip the glass upside down. The polymer should absorb the water, expand, and stay inside the cup, making it look like the water disappeared.
  • Fake Snow
    • You can inexpensively buy enough sodium polyacrylate that you can fill a kiddie pool (or larger!) sized area with fake snow that kids can play in for a Frozen themed party or what-not.
  • Fluffy Slime
    • Add it to your favorite slime recipe for a whole new feel

Paper Towel Rainbows: Chromatography for Beginners

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Get ready for all the rainbow heart eyes in this easy and gorgeous introduction to chromatography. 🌈😍 Recommended age 3.5+

This activity focuses on the concept of solubility and how an appropriate solvent can carry molecules along a stationary phase. Read on for some basic science and how to make some jaw dropping art!

Materials

Method

  1. Cut squares from a paper towel (four from a large sheet or two from a select-a-size sheet).
  2. Find the center of sheet and using different color Sharpies, heavily color in dots around the center point. Make sure the dots have a lot of ink in them, but don’t puncture the paper towel.
  3. Using the eye dropper, drop isopropanol onto the center of the paper towel and watch as the ink radiates out from the center. Keep slowly adding isopropanol to grow your chromatograph.
  4. Use your science art to make new crafts or hang it up to display!

Extra Experiments and Questions

  • Try doing this with water instead of isopropanol. Does it work? What’s happening?
  • Try doing this with washable markers (like Crayola). Which works better- water or isopropanol?
  • Do you think this would work with crayons?
  • How does this relate to stain removal? Why can’t you wash Sharpie out of your clothes with water?
  • Try putting less ink on the dots and see if you can separate some of the colors within the ink. The success of this will vary on the markers/colors you use, but its worth a shot!

Discussion

Chromatography is used frequently in labs to separate compounds in a mixture. There are many types of chromatography but they are all based on a similar concept: a mobile phase carries your molecules of interest through a stationary phase, and based on the different interactions with the mobile and stationary phase, the different compounds can be separated. This experiment illustrates how a solvent (the isopropanol) can carry soluble molecules (the ink) through a stationary phase (the paper towel). After kids grasp this concept, you can move on to more delicate examples of chromatography like separating the components of fall leaves or a bouquet of flowers. See below for some key definitions to go over.

Definitions

Chromatography: A way to separate parts of a mixture by moving the mixture and a solvent (mobile phase) along a surface (stationary phase). Because the different parts of the mixture will “prefer” to be on the stationary phase or mobile phase differently, they travel at differing rates, causing the parts to separate.

Solubility: A demonstration really helps to explain this to kids. They first must know that everything is made up of smaller parts, like molecules, ions, or atoms. Mix sugar or salt into warm water and show them that it seemingly disappears into the water. Explain that the smaller parts are being broken off from the larger crystal and surrounded by water molecules, which keeps them suspended in the liquid. They are still there, we just can’t see them. Then try doing this with chalk or something else that is not soluble in water. They will be able to see the bulk either floating or sinking to the bottom. Explain that these things are insoluble. The sugar or salt have properties that make them want to associate with water, kind of like magnets sticking to each other, while the chalk molecules do not.

In this experiment, the ink from Sharpies is soluble in isopropanol but not in water. The isopropanol is called a solvent, and the ink molecules are called the solute.

Mobile Phase: In this experiment, the mobile phase is the isopropanol. It carries the ink molecules along the paper towel through capillary action.

Stationary Phase: In this experiment, the stationary phase is the paper towel. If solute molecules interact strongly with the stationary phase, they will stick to it earlier than molecules with less attraction to it.


Share the art you create with this project on Instagram and join our community! Tag us and use the hashtag #IBravedTheElements for a chance to be featured!

xoxo

 

Cara