Powershell: using get-member to return object properties

I'm trying to browse all of the items in a sql server object.
I'm working with a SQL server cluster and am using this code (lifted from another page) to get the values from 2 specific items.

[System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.Smo') | out-null;
$srv = New-Object 'Microsoft.SqlServer.Management.Smo.Server' $cluster_name;
$properties = $srv.Properties
$owner_node = $properties.Item('ComputerNamePhysicalNetBIOS').Value;
$is_clustered = $properties.Item('IsClustered').Value

This led me to wonder: How would I browse the other items in this object?
When I try "$properties | get-member" , it just returns:

 TypeName: Microsoft.SqlServer.Management.Smo.Property

Name        MemberType Definition                      
----        ---------- ----------                      
CompareTo   Method     int CompareTo(System.Object obj)
Equals      Method     bool Equals(System.Object o)    
GetHashCode Method     int GetHashCode()               
GetType     Method     type GetType()                  
ToString    Method     string ToString()               
Dirty       Property   System.Boolean Dirty {get;}     
Expensive   Property   System.Boolean Expensive {get;} 
IsNull      Property   System.Boolean IsNull {get;}    
Name        Property   System.String Name {get;}       
Readable    Property   System.Boolean Readable {get;}  
Retrieved   Property   System.Boolean Retrieved {get;} 
Type        Property   System.Type Type {get;}         
Value       Property   System.Object Value {get;set;}  
Writable    Property   System.Boolean Writable {get;}  

The same result is returned when I try "$properties.item | get-member".