act4.tex

\documentclass[12pt]{article}
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\title{Physics \\
Activity \#2: What's the matter?}
\author{Al-buharie Amjari, STEM-A 12}

\makeatletter % from: https://tex.stackexchange.com/a/101263/134144
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\title{Physics \\
Activity \#4: BE A SCIENCE DETECTIVE}
\author{Al-buharie Amjari, STEM-A 12}

\begin{document}
\maketitle
%\textbf{Based on the kinetic molecular model, solids usually have higher densities
%compared to liquids. However, ice, a solid form of H2O floats on liquid
%water which means ice is less dense than water. What do you think is
%the reason for this phenomenon? What is the biological significance of
%this concept?}


\textrm{H$_2$O} have certain properties when its average kinetic energy is lower.
To put it simply, it forms little empty pockets when no kinetic energy is stopping
this pockets from breaking down. Technically, in a polar molecule \textrm{H$_2$O},
Oxygen have more electronegativity than the Hydrogen. This imbalance in the
electronegativity makes the Hydrogen hungry ($+\delta$) and the Oxygen full ($-\delta$).

\begin{center}
\chemname{\chemfig{\charge{90:1.5pt=$\scriptstyle+\delta$}{H}-[:30]\charge{90:1.5pt=$\scriptstyle-\delta$}{O}-[:-30,,1]\charge{80:1.5pt=$\scriptstyle+\delta$}{H}}}{Water}
\end{center}

With this imbalance, Hydrogen forms a weak bond with the other Oxygen
in the neighbor
molecule, forming a regular hexagonal pattern when it's cooled to $0^\circ$:


%\begin{center}
%\tiny
%\chemname{\chemfig[fixed length=true,atom sep=1.25em]{H-[:30]O-[:-31]H-[:-30,,,,dotted]O(-[:270]H-[:-90,,,,dotted]O-[:210]H)-[:30]H}}{Hexagonal pattern of solid ice}
%\end{center}
\begin{center}
\small
\chemname{\chemfig[fixed length=true,atom sep=1em]{H<[:-90]O(<:[:60]H)-[:-30,,,,dotted]H-[:-30]O-[:-90]H-[:-90,,,,dotted]O(<[:-45]H)(<:[:-60]H)-[:210,,,,dotted]H-[:210]O-[:-210]H-[:-210]O(<[:240]H)(<:[:225]H)-[:90,,,,dotted]H-[:90]O-[:30]H-[:30,,,,dotted]}}{Hexagonal pattern of solid ice (I$_\textrm{h}$)}
\end{center}

This pattern also forms in its liquid state but it immediately and easily breaks down as its weak
(or might not form at all).

%There exist a form of ice which is dense than water (so ice sinks), and it can be obtained by introducing
%high pressure and cold to \textit{High Density Amorphous Ice} resulting into \textit{Very High Density Amorphous Ice}\footnote{\url{https://en.m.wikipedia.org/wiki/Amorphous_ice\#Very-high-density_amorphous_ice}}, with density
%of about 1.26g/cm$^3$, so it sinks in a water of density, 1g/cm$^3$ (assuming that that ice can exist for a
%moment at pressure 1atm at room temperature.)
%
%\begin{center}
%\href{https://www.thoughtco.com/does-heavy-water-ice-float-607732}{\includegraphics[width=1.5in]{sink.jpg}}
%\end{center}
%

\end{document}