Depending on the version of FileMaker you are using, you could play around with the object anchors available in the "Object Info" box.
Another option would be to create 2 different layouts and control the navigation via scripts to determine which mode you are on.
I am using filemaker pro 10 advanced.i know abt anchors but how it can be used to incresae the size of the objecys.what i want is that i want to increase the size of the objects that is on the layout in kiosk mode.
Let's say, for example, that you design a layout that is 800 x 600 pixels. You anchor the an object to the Left, Right, Top, and bottom...
Now if you expand that window larger than the 800 x 600, you will see the object increase in size to accommodate. That won't increase the text size...but whatever objects you want to resize, will resize. If you need everything to be a different size (like fonts, etc) you will need a separate layout.
Actual Layout Size ( Image from SixFriedRice Blog )
Resized Layout with Object Anchors On