We got to take our 1st field trip this year...The city sponsors a fantastic water festival for 4th graders every year. Our science curriculum spends a lot of time on water and this event has so many hands on real life applications that students totally connect to it.
Before a field trip we create (or later refer to) an anchor chart outlining the criteria for success.
We also do an anticipatory/summarizing activity. Thoughts Of a Third Grade Teacher has this Great Anchor Chart
Before we leave students write down one thing they hope to learn or one question they would like to ask a presenter. When we return they write down 3 things they learned, 2 things they found interesting or two new words they heard, and 1 question they still have. Its called a 3,2,1 summary strategy and I just add the anticipatory question to get more bang for my buck.
One of my colleagues husbands happened to be a presenter, he works for the public works department taking care of water main breaks..boy did my kids fire questions at him...I noticed most of the questions were the ones they had written down. They stumped him with some specifics but they were also able to come back with some complex facts about water.