Using UI 1.12.1 Does not work

Using UI 1.12.1 Does not work

I just downloaded UI 1.12.1. both jquery-ui.js and jquery.js are in the same fold my html page is in.
I proceeded to review a jQuery tutorial and copied the sample; ran it in Firefox:nothing worked.
I have tried .hide(), .append(), and alert(); no jQuery script works, nada, zero, and zip works.

Regular JavaScript still works.

This is my code:
Why doesn't this work?
  1. <body>
      <div id="divOne">
        
          <p id="pOne">
      
          </p>
        <p id="pTwo"> This 2</p>
       
      </div>
     
     
      <script>
      document.write("Ready");
     
      $(document).ready(function(){
        alert("Helllooo!"); 
       $("#pOne").append("Changed");
       $('#pTwo').text('did I change?');
       
      });
     
         
      </script>
     <script src="jquery-ui.js"></script>
      <script src="jquery.js"></script>
  2.  <script src="jquery-ui.css"></script>
    </body>