diff --git a/main.tex b/main.tex
index c41fb1e..f2ebbef 100644
--- a/main.tex
+++ b/main.tex
@@ -144,7 +144,23 @@
 \rule{\linewidth}{0.25pt}
 \end{center}
 
-\section{First}
+\section{Equations}
+\subsection{Navier-Stokes}
+\begin{equation}
+    \frac{D}{Dt}
+\end{equation}
+
+\subsection{Circulation}
+\begin{equation}
+    C = \oint_c u \, dc = \oint (u \, dx + v \, dy + w \, dz)
+\end{equation}
+
+\section{Concepts}
+\subsection{Thermal wind}
+\textit{Thermal wind} describes the vertical change of geostrophic (i.e. horizontal) wind
+\begin{equation}
+    \frac{\partial}{\partial z} v_G = \bigg(\frac{1}{f}\frac{g}{\theta_0}\bigg)(k \times \nabla_h \theta^*)
+\end{equation}
 
 \scriptsize