Though emails, Snapshot and Instagram have certainly taken over the old habit of postcard writing, many people still love getting a paper postcard delivered the traditional way to their mail box.
You will create your own postcard to send to your classmates. You will use Post Card Creator for the text and then include a pics of any of the places you will visit in your trip.
In your travel project, you will have to include a postcard. Writing a virtual or traditional postcard follows certain conventions.
Here follows a good interactive model of postal writing from the British Council. Do the on line exercises complete the downloadable worksheets you will find at the bottom of the page.
You could also have a look at this postcard sent from New York