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Lesson plan Kindergarten Science

The Sunshine Water Bag: A Kindergarten Water Cycle Lesson

A 30-minute kindergarten lesson in which the class tapes a bag of tinted water to a sunny window, predicts what will happen, and narrates the setup in order.

Objectives

  1. Students will predict what will happen when a bag of water is taped to a sunny window.
  2. Students will narrate, in the correct order, the steps of setting up the water bag.
  3. Students will observe and describe the water bag's changes over several days, connecting them to that day's weather.

Vocabulary

Key words: evaporate, droplet, sunny, cloudy

Teacher overview

This lesson sets up a simple, safe demonstration that keeps giving the class something to observe all week: a clear bag holding a little blue-tinted water, taped flat against a sunny window. Over the coming days, warm sunlight turns some of the water into invisible water vapor, which then cools and collects as tiny droplets on the inside of the bag, where students can watch them collect and slide down, a miniature and visible version of water moving from a liquid into the air and back again. A common idea this lesson corrects gently is that once water disappears from a cup or puddle, it is simply gone; watching droplets reappear inside the sealed bag over several days shows students that the water is still there, just changed.

Today's lesson is the setup: predicting, building, and narrating the steps in order. Each following morning, the class can return to the bag for a two-minute observation and add one word or drawing to a shared class chart, without needing a second full lesson period.

Procedure

Minutes 0-5 -- Hook. Hold up an empty zip-top bag and a cup of warm blue water. Ask: "If I put this water inside the bag, seal it, and tape it to our sunny window, what do you think will happen by tomorrow?" Take three or four guesses without confirming or correcting any of them.

Minutes 5-13 -- Direct instruction and setup. Explain in simple words: "The sun warms the water inside the bag. Some of the water changes into an invisible gas called vapor and floats up inside the bag. When it touches the cooler plastic near the top, it turns back into tiny drops of water, called droplets." Pour about a cup of the blue water into the bag together, seal it carefully, and check for leaks by gently squeezing.

Minutes 13-20 -- Predict and draw. Each student draws what they think the inside of the bag will look like tomorrow: still just water at the bottom, droplets on the sides, or something else. Circulate and ask one or two students to say their prediction aloud to a partner.

Minutes 20-25 -- Tape and narrate. Tape the bag flat against the sunny window as a class. Ask four volunteers to each say one step in order, acting out the motion: "First we poured the water in. Next we sealed the bag. Then we taped it to the window. Now we wait." Repeat the four steps together as a class chant.

Minutes 25-30 -- Closure and formative check. Ask the whole class to retell the four steps in order using hand motions (a pouring motion, a zipping motion, a taping motion, hands folded to "wait"), without looking at the bag; if most students can complete all four motions in the right order, the sequencing goal for today is met. Tell students tomorrow's job is to check the bag first thing and report what changed.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Retell check: Ask a student to name the first step of setting up the water bag. Answer: Pouring the warm blue water into the bag, which happened before sealing, taping, or waiting.
  2. Retell check: Ask a student to name the last step before the class started waiting. Answer: Taping the sealed bag to the sunny window, which came after pouring and sealing.
  3. Observation check (for a later morning): Ask what the small drops on the inside of the bag are made of. Answer: Water that came from inside the bag itself, warmed by the sun until it changed into vapor and then cooled back into droplets on the plastic.

Differentiation

Support

Provide four picture cards showing the pouring, sealing, taping, and waiting steps, and have students place them in order on their desk before retelling the sequence aloud. Pair the prediction drawing with a simple two-choice picture (dry bag or bag with droplets) that students circle instead of drawing from scratch.

Extension

Ask students to also predict what might happen if the same kind of bag were taped to a shady window instead of a sunny one, and explain their reasoning using the word "because." During the week's daily checks, invite these students to describe whether that day's droplets look like more, fewer, or about the same as the day before.

ELL supports

Pre-teach evaporate, droplet, sunny, and cloudy using simple gestures (fingers wiggling upward for evaporate, a pinching motion for droplet) that the whole class practices during setup. Allow the retell check to be answered fully through the hand-motion sequence rather than spoken words, and pair each vocabulary word with its gesture on a small picture card taped near the window.

Extensions

Each morning for the rest of the week, spend two minutes at morning meeting checking the bag together, marking that day's weather (sunny or cloudy) on the class weather chart, and adding one word or drawing describing the droplets to a shared class chart, building a simple week-long record students can look back on. At the end of the week, open the bag over a bowl during a science talk and let students see and feel that the water is still there, connecting the whole week's observations back to the idea that water changes form but does not disappear.