ACS: Inquiry in Action - Matter is Made of Tiny Particles (Lesson 1.4): The Water Cycle

Students use water, ice, and plastic wrap to model the ocean and cold upper atmosphere to investigate the question: What are the main processes in the water cycle that make it rain?


Students will be able to develop and explain a particle-level model to describe evaporation and condensation in the context of the water cycle.

Key Concepts

  • The water cycle depends on the processes of evaporation and condensation.
  • Evaporation happens when water molecules at the surface of a liquid move fast enough to break away from other water molecules and escape from the liquid into the air.
  • Condensation happens when water molecules in the air slow down enough to join together to form liquid water.
  • In the water cycle, water from lakes, rivers, and oceans evaporate and enter the atmosphere where it cools, condenses into liquid water, and comes back to Earth as rain.

NGSS Alignment

  • NGSS 5-PS1-1: Develop a model to describe that matter is made of particles too small to be seen.


Students have been introduced to the idea that matter is made up of tiny particles that are too small to see. They have investigated these atoms and molecules in the context of dissolving and evaporation. In this lesson:

  • Students build on these ideas by creating a physical model of the water cycle.
  • Students use water, ice, and plastic wrap to model the ocean and cold upper atmosphere.
  • Students use observations from their model to explain the processes of evaporation and condensation that drive the water cycle.


Download the student activity sheet and distribute one per student when specified in the activity. The activity sheet will serve as the Evaluate component of the 5-E lesson plan.

Science Topics
Chemistry, Hydrology, Matter, Solubility & Saturation
K-6, Educator
5th Grade
Descriptions of PDFs

Lesson Plan (PDF) | Student Activity Sheet (PDF) | Student Reading (PDF) | Teacher Background (PDF) | Connections to NGSS (PDF)

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