Fill a cup with water and put shaving cream on top to act as a cloud.  Explain to students that when clouds get really heavy with water, it starts to rain.  Add some blue food coloring drops to the top of the shaving cream and watch it start to rain!  http://secondgradesugarandspice.blogspot.ca/2012/02/written-directionstricks-anyone-freebie.html

We read “It Looked Like Spilt Milk” by Charles Shaw, which illustrates how clouds come in all different shapes and sizes. Then, I had students rip papers to make clouds, glue or tape their clouds onto paper, and follow the format of the book to write what their paper cloud looked like.

Summary: This is an excellent opportunity for students to demonstrate their understanding of the different types of clouds and create a great display for your room.
During a weather unit, students typically learn about the different types of clouds they may see in the sky. This is a great way for students to synthesize this information. The work below was created by a 1st grade class.

http://lesson-plans.theteacherscorner.net/science/earth/

Take pieces of blue construction paper, fold in half, and then cut within about 1/4 of an inch of the fold. (You will need to divide the paper into thirds and make just two cuts.) On the outside of the folded paper, students draw and label the type of cloud. On the corresponding inside flap, they “predict” the type of day you would have if this cloud was in the sky.

http://adventuresinmommydom.org/clouds-unit/

http://www.weatherwizkids.com/weather-clouds.htm

http://elementary-excellence.blogspot.ca/

http://www.moorefuninfirst.com/2012/03/weather-unit.html

http://theinspiredapple.blogspot.ca/search?q=weather

http://secondgradesugarandspice.blogspot.ca/2012/02/written-directionstricks-anyone-freebie.html

http://bogglesworldesl.com/watercycle_worksheets.htm

http://www.itsybitsyfun.com/water-cycle-worksheet.html