Place second list at same position as first list in beamer overlay

Question

I like to have the second itemize list to appear at the top of the frame, i.e. at the same place as the previous itemize list. At this frame I have two columns where each item on the left column are associated with several items which I like to be appeared on the right column after each item on the left column. Then, item list associate with first item on right should disappear and again the item list associate to second item on the left should start from the top of the frame.

\documentclass{beamer}

\mode<presentation> {

\usetheme{Hannover}
\usecolortheme{seagull}
}
\usepackage{graphicx}
\usepackage{booktabs} 
\usepackage{siunitx} 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{document}
\begin{frame}
\frametitle{ applications}

\begin{columns}

    \begin{column}{0.4\textwidth}

    \begin{itemize}
   \setbeamercovered{transparent}
\item <1-5> {\small Combustion}
\item<6-> {\small Airborne }
\item<10->{\small Environmental}

\end{itemize}

\end{column}

\begin{column}{7cm}

\begin{itemize}[label={}]

\item[] <2-5>{\tiny PN$\mathrm{_{ d< 1\,\si{um}}}$ $\gg$ PN$\mathrm{_{ d> 1\,\si{um}}}$     }
\item[] <2-5>{ \tiny A correlation }
\item[] <3-5>{\tiny No universal }
\item[] <4-5> {\tiny limited}

\end{itemize}

\begin{itemize}[label={}]

\item[] <7-7>{\tiny PN$\mathrm{_{ d< 1\,\si{um}}}$ $\gg$ PN$\mathrm{_{ d> 1\,\si{um}}}$     }

\end{itemize}

\end{column}

\end{columns}

\end{frame}


\end{document} 

Answer 1

You can use an overprint environment with an \onslide before each itemize. Schematically

\begin{column}{0.55\textwidth}
  \begin{overprint}
    \onslide<2-5>
    \begin{itemize}
    \item<2-5> text 
    \item<3-5> text
    \end{itemize}
    \onslide<7>
    \begin{itemize}
    \item<7> text
    \end{itemize}
  \end{overprint}
\end{column}

On slide 5 you then have

and slide 7 has

\documentclass{beamer}

\mode<presentation>{
\usetheme{Hannover}
\usecolortheme{seagull}
}

\usepackage{siunitx}
\sisetup{detect-all}

\newcommand{\PN}{\textsf{PN}}

\begin{document}

\begin{frame}
  \frametitle{applications}

  \begin{columns}
    \begin{column}{0.4\textwidth}
      \small
      \begin{itemize}
        \setbeamercovered{transparent}
      \item<1-5> Combustion
      \item<6-> Airborne
      \item<10-> Environmental
      \end{itemize}
    \end{column}

    \begin{column}{0.55\textwidth}
      \tiny
      \begin{overprint}
        \onslide<2-5>
        \begin{itemize}
        \item[]<2-5>$\PN_{\mathrm{d}< \SI{1}{um}} \gg
          \PN_{\mathrm{d}>\SI{1}{um}}$
        \item[]<2-5>A correlation
        \item[]<3-5>No universal
        \item[]<4-5>limited
        \end{itemize}
        \onslide<7>
        \begin{itemize}
        \item[]<7>$\PN_{\mathrm{d}< \SI{1}{um}} \gg
          \PN_{\mathrm{d}>\SI{1}{um}}$
        \end{itemize}
      \end{overprint}
    \end{column}
  \end{columns}
\end{frame}

\end{document}

I have tidied up several other aspects of your code

• moved the text sizing commands outside of the lists, as they applied to all elements
• used \SI{1}{um} rather than 1\,\si{um} for print numbers with a unit, and added the detect-all feature so the font matches
• collected math expressions in to single units, with a command to typeset PN in the sans font
• specified the second column width relative to the textwidth
• replaced overlay specification <7-7> by <7>