chemistry, Crafty, Experiments, Physics, Together with sis

Physics Experiments: Capillary Bowl

Simon really wanted to try building a capillary bowl – a version of a perpetual motion machine in which water circulates. Although aware of the fact that perpetual motion was not possible, he is keen on seeing it for himself. Off we were to the hardware store where we got some funnels and hoses. What we observed was Pascal’s law in action: the level of water evened out and there was no way to get the water rise higher at one end of the hose than at the other and thus no way to get the water flow into the funnel.

Eventually, we did manage to get the capillary bowl to work for a split second when we filled it with coke and beer. The pressure of water is higher than that of foam, because liquid has a higher density than foam. We used alcohol free beer, so there wasn’t that much foam.

chemistry, Experiments, Physics, Together with sis

Chemistry Experiments: Colors (surface active agents and pH indicator)

Our new MEL Chemistry box arrived, containing tons of color fun! We have already tried two experiments. In the Color changing milk experiment, the soap touches the milk creating a very thin film of soap on the milk’s surface and causing the colors to spread along with it, producing a mesmerising effect. Molecules of soap and other similar substances lower the surface tension of different liquids and thus are called surface-active agents (SAA). Simon took it a notch further and created antibubbles that glide on the film of soap:

 

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We thought this one looked like a nuclear explosion:

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The second experiment we did was called Magic Liquid and felt like performing a magic trick: a yellowish liquid poured in five different cups turned five different colors, almost all the colors of the rainbow! The secret was putting a tiny bit of a different chemical substance on the bottom of every cup beforehand. The yellowish stuff was actually Thymol blue, also known as thymolsulfonephthalein (chemical formula C27H30O5S ), a pH indicator, and changed color according the acidity of the substances that were already in the cups. The larger the quantity of protons H+, the higher the acidity of the medium, while the OH ions are responsible for the basic medium:

 

Thymol blue molecule visible on the iPad screen:

We also checked the pH of the substances using indicator standard teststrips:

The pH rainbow:

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Simon had already been busy with colors for a few days, revisiting his Magformers collection to build this gorgeous color wheel:

We later repeated the MEL Science demos for Simon and Neva precocious friend:

 

chemistry, Milestones, Notes on everyday life, Physics, Together with sis

The way to own your knowledge

Simon went further on his research about what exactly valence is, and what determines how many other atoms an atom can bond with. “What about Helium? My question is, how many bonds does Helium have?” I hear him ask and watch as he searches the internet for a chemical bonds table. “From this table, I can see that the amount of bonds is not equal to the amount of electrons in the last orbital, the amount of valence electrons!” But what is the algorithm to calculate the valence of every element? He then discovered that the information about it hides inside the periodic table where elements are divided into groups. But those groups are more about the number of the valence electrons.” Mom, it says 7 for chlorine, but in my Chemistry modeling set chlorine has just one hole!” Something didn’t add up. I suggested we look into Theodore Gray’s Molecules book, which we only have in Dutch. There we studied the drawings of the outer layers of the “schil” of different atoms (in Dutch, the orbital cloud is called “schil”, which is the same as the peel of an apple). And all of a sudden, Simon knew it. He started shaking, his body stiffened with excitement. He realized that the element’s valence is the number of electrons the outer orbital can take minus the number it already has! That is, the number of “holes”, of vacancies! What a feast it was to see how he made this huge discovery all on his own, how he physically felt the discovery strike his mind and pierce his body like an envigorating wave, and how now he owned that knowledge, something he was genuinely interested in and something he experienced so deeply.

What Simon did then was grab ping-pong balls and little atoms from his modeling set and invite me and Neva to play with him, as if we were the unhappy elements that missed electrons in our outer shells and we started exchanging our ping-pong balls (our electrons) to form happy and complete molecules. And then he took two balls and gave two balls to me and said: “I don’t need you. I’m Helium and happy alone”, a big smile on his face at he made the joke.

Here we pretend we are two oxygen atoms trying to form a molecule. The white balls are how many valence electrons each of us has.

Making atom models from clay together with sis. The blue clay balls are electrons and the red ones are protons.

chemistry, Physics, Simon's sketch book

Valence and bonds

Simon has been down with a serious flu for the past three days and yet, the moment he started feeling just a little more alive he resumed his learning: following Physics Girl and Veritasium tutorials, reading up on valence quarks and the bonds between elements. And as soon as the fever was gone, he started sharing what he learned with me again (on fluid dynamics and turbulent and laminar boundaries, on quantum spin and entanglement) the old enthusiastic Simon was back!

chemistry, Experiments, Physics, Together with sis

MEL Chemistry Box number 3: Artificial Snow and growing crystals on a Xmas tree

Our third MEL Science box arrived back in August, when we were on vacation. We have already tried two experiments from the box, both perhaps more suitable for winter. Instant Snow, using sodium polyacrylate (the stuff you can find in diapers):

And growing salt crystals on a paper Christmas tree:

chemistry, Experiments

The second set of MEL Chemistry experiments

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Today we opened our second MEL Chemistry box with two experiments using tin (Sn). We made a tin dendrite and grew a tin hedgehog. Both experiments involved preparing a tin chloride SnCl2 solution (by mixing tin chloride with a sodium bisulfate). In the first experiment, we had electric current flow through the solution (by connecting it to batteries via crocodile clips), so it acted like an electrolyte. A tin reduction reaction took place: Sn2+(solution) + 2e→ Sn(solid)

The tin dendrite grows in the direction that the electric current flows through the solution; from one clip towards the other:

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In the second experiment, we simply dropped a piece of zinc into the tin chloride solution. What happened as a result was a substitution reaction: some zinc dissolved into the solution, while tin precipitated on the surface of the zinc pellet in the form of lovely needles:

SnCl2 + Zn → Sn + ZnCl2

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chemistry, Experiments, Physics

Our first MEL Chemistry set has arrived!

We have received our first MEL Chemistry box, something the kids were really impatient to start. And guess what, finally something to be proud of being a Russian from St.Petersburg – that’s where MEL Science kits are actually being made! It’s been a while since I have seen a “Made in Russia” on anything awesome.

The first two experiments we tried today were part of the Artificial Sea Set: Chemical Seaweed and Chemical Jellyfish. They both involved working with metal salts (sulphates) and watching them react with different solutions. The time lapse video above shows the seaweeds “growing”: “Metal salts gradually dissolve and react with the potassium hexacyanoferrate(II). Insoluble copper, iron and zinc compounds form. These don’t just precipitate out but form “bubbles” because of the osmotic pressure. The fancy chemical seaweed grows from these bubbles”.

It was fun to watch the metal salts change colours: iron turned bright blue and blue copper sulphate turned brownish red!

The funny little things in the petri dish are the “jellyfish” we made as a finishing touch to our artificial sea. We created theses by firing metal salt solutions into sodium silicate (liquid glass). “An ion exchange reaction occurs between the sodium silicate and the metal salts. As a result, insoluble metal silicates form. These resemble jellyfish!”

Metal salts starting to grow in potassium hexacyanoferrate:

Unboxing the first kit:

Busy with the experiment(s):

We also dived into the MEL Chemistry app that allows you to see all the molecules of the reagents involved in 3D.

chemistry, Coding

Salts and Metals

Another fun chemistry workshop today with John Maas: solubility of salts, metal dissolving in acid and burning like a star, and other interesting lab tests and the theory behind them.

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The reaction above is this:

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In the video below Simon and John are enhancing the collision between oxygen and hydrogen molecules by adding fire. Simon loved the funny sound you hear when that collision happens:

Simon’s notes:

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