This is a recording of a recent live teleclass I did with thousands of kids from all over the world. I’ve included it here so you can participate and learn, too! (Click here if you’re looking for the more recent version that also includes Chemical Engineering.)
When you think of slime, do you imagine slugs, snails, and puppy kisses? Or does the science fiction film The Blob come to mind? Any way you picture it, slime is definitely slippery, slithery, and just plain icky — and a perfect forum for learning real science. But which ingredients work in making a truly slimy concoction, and why do they work? Let’s take a closer look…
Materials:
- Sodium tetraborate (also called “Borax” – it’s a laundry whitener) – about 2 tablespoons
- Clear glue or white glue (clear works better if you can find it) – about 1/2 cup
- Yellow highlighter
- Pliers or sharp razor (with adult help). (PREPARE: Use this to get the end off your highlighter before class starts so you can extract the ink-soaked felt inside. Leave the felt inside highlighter with the end loosely on (so it doesn’t dry out))
- Resuable Instant Hand Warmer that contains sodium acetate (Brand Name: EZ Hand Warmer) – you’ll need two of these
- Scissors
- Glass half full of COLD water (PREPARE: put this in the fridge overnight)
- Mixing bowl full of ice (PREPARE: leave in freezer)
- Salt
- Disposable aluminum pie place or foil-wrapped paper plate
- Disposable cups for solutions (4-6)
- Popsicle sticks for mixing (4-6)
- Rubber gloves for your hands
- Optional: If you want to see your experiments glow in the dark, you’ll need a fluorescent UV black light (about $10 from the pet store – look in cleaning supplies under “Urine-Off” for a fluorescent UV light). UV flashlights and UV LEDs will not work.
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Key Concepts
If you’ve ever mixed together cornstarch and water, you know that you can get it to be both a liquid and a solid at the same time. (If you haven’t you should definitely try it! Use a 2:1 ratio of cornstarch:water.) The long molecular chains (polymers) are all tangled up when you scrunch them together (and the thing feels solid), but the polymers are so slick that as soon as you release the tension, they slide free (and drips between your fingers like a liquid).
Scientists call this a non-Newtonian fluid. You can also fill an empty water bottle or a plastic test tube half-full with this stuff and cap it. Notice that when you shake it hard, the slime turns into a solid and doesn’t slosh around the tube. When you rotate the tube slowly, it acts like a liquid.
Long, spaghetti-like chains of molecules (called polymers) don’t clump together until you cross-link the molecule strands (polymers) together into something that looks more like a fishnet. This is how we’re going to make slime.
What’s Going On?
Imagine a plate of spaghetti. The noodles slide around and don’t clump together, just like the long chains of molecules (called polymers) that make up slime. They slide around without getting tangled up. The pasta by itself (fresh from the boiling water) doesn’t hold together until you put the sauce on. Slime works the same way. Long, spaghetti-like chains of molecules don’t clump together until you add the sauce – something to cross-link the molecule strands together.
The borax mixture holds the glue mixture together in a gloppy, gelatinous mass. In more scientific terms, the sodium tetraborate cross-links the long polymer chains in the glue to form the slime.
Why does the slime glow? Note that a black light emits high-energy UV light. You can’t see this part of the spectrum (just as you can’t see infrared light, found in the beam emitted from the remote control to the TV), which is why “black lights” were named that. Stuff glows because fluorescent objects absorb the UV light and then spit light back out almost instantaneously. Some of the energy gets lost during that process, which changes the wavelength of the light, which makes this light visible and causes the material to appear to glow.
Questions to Ask
- What happens when you freeze your slime? Is there a color change?
- How long does it take to thaw your slime in the microwave?
- Do you see the little bubbles in your slime?
- How many states of matter do you have in your slime now?
- Does this work with any laundry detergent, or just borax?
- What happens if you omit the water in the 50-50- glue-water mixture, and just use straight glue? (Hint – use the glow juice with the borax to keep the glowing feature.)
- Does your slime pick up newsprint from a newspaper?
- What other kinds of glue work well with this slime?
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Technically, fire does not fall into a fundamental state of matter. It is most like plasma, but portions could be categorized as gas.
Most of the materials in the list on this page can be found at stores such as Target and Wal-Mart.
What state of mater is fire?
In what stores can I find materials?
WOW! I did the Crystallizing a Supercooled Liquid and it worked! My family were watching when I dropped the ice block in the glass and they were amazed at how quickly it froze! This science program has been great and I can’t wait to do more experiments and teleclasses! Thank you so much for letting me join you (:
This particular video doesn’t have a workbook. All work is explained was we go through the class.
Hey Aurora, I was just wondering if there’s a work book to fill out through the video? Cheers!
That pouch should work because it has sodium acetate. The behavior you described is expected. After you crystalize the compound, you need to heat it up to melt it back into a liquid. The process is described in the video on this page, but the procedure is also describe under item #10 on this page: https://www.sciencelearningspace2.com/2019/07/summer-science-activities-for-your-kids/
Hi Aurora, we got a different brand of hand warmers of Amazon because it took less time to ship. They claim to contain 12% distilled water, 88% sodium acetate. As soon as we cut open a corner of the liquid ones they immediately started crystalizing, so we couldn’t pour out the liquid to make the experiment. We tried that with two of them. Why would that happen? Thank you.
When the slime is dropped, the cross linked long chain molecules try to hold their position, which causes the “bounce”.
I found that the slime was more flexible and stretchy when it was warm, then when it got cold. Also do you know why the slime bounces as much as it does because I have made other types of slime and they didn’t really bounce they just fell on the counter top and lied flat.
You really need sodium acetate for this experiment. Best thing is to buy the ones we recommend in the supply list above.
We got grabber handwarmers, they were the only ones they had at the store for this experiment…doesn’t look like they have sodium acetate in them… any other materials we may have at home that we can substitute for this experiment? We are dying to make the slime…. Thanks!!!
Protons and neutrons are made up of sub-atomic particles called quarks. Electrons are just electrons and aren’t made out of anything smaller. Because of this, electrons are considered an elementary particle.
What is inside the protons,neutrons and electrons?
Wrap it in a kitchen towel and place in a pot of water. Bring to a boil for about 5 minutes, and then remove gently with tongs. Let it cool, and then unwrap – you should see the solid now all a liquid.
For the hot icicle experiment – I only have one hand warmer. Do I get the crystal out before letting it melt? Is there a way to safely boil it at that point or do I wait for it to melt at room temperature?
okambon: I found the correct hand warmers on Amazon by typing in sodium acetate hand warmers. Hope that helps!
Is there anything else that can be used besides the EZ hand warmers? I cant find them anywhere where we live. I have been everywhere. Can we use anything else?
(Leave the felt inside highlighter with the end loosely on (so it doesn’t dry out))…. I knew I would need some for this teleclass so I’d cut some out the night before and put it on my desk… It dried out. Thanks though! <3
Oh, no! We actually are changing it so that you have full access to all the units in the level you subscribe to. Originally we incremented the content because folks were upset that there was too much content, so we stepped it down and walked them through it… only now folks are upset because they don’t have access to everything, so we switched it back. It was well-intended, but just didn’t work for everyone!
You should have access now, but if you still don’t, I’ll have Tonya follow up with you.
I have been an e science member for a while now. But I still don’t have access to a lot of the units and parts of the units. For example: I don’t have access to any of these teleclasses. Is it possible to get access to these?
Is it possible to have access to this teleclass?
I’ll have someone contact you right away to get this straightened out!