Lesson plan Grade 1 Science

The Dried Drop Test at Mottlebeck Creek: A Grade 1 Lesson

Two jars look identically clear, so the class dries one drop from each on dark paper and reads what is left behind as evidence about what the water holds.

Grade: Grade 1
Subject: Science
Material: Lesson plan
Time: 45 min
Prep: Moderate prep
Materials: Three labeled clear plastic jars with lids, prepared before class, A spoon of garden soil for the second jar and two spoons of table salt for the third, Black or dark blue construction paper cut into small squares, three squares per group, An eyedropper or a straw for moving one drop from each jar, A sunny windowsill or a desk lamp to dry the drops, Chart paper and a marker for the class vote chart

Standards

1.MD.C.4 Common Core Math

Organize, represent, and interpret data with up to three categories; ask and answer questions about the total number of data points, how many in each category, and how many more or less are in one category than in another.

How this material aligns: The hook records a clean or not-clean vote for each jar on a two-category chart, and handout item 5 asks how many more classmates called the clear salt jar clean than called the cloudy soil jar clean.

All materials for 1.MD.C.4 →

W.1.2 Common Core ELA

Write informative/explanatory texts in which they name a topic, supply some facts about the topic, and provide some sense of closure.

How this material aligns: Handout items 7 and 8 have students write about testing water, giving a reason that looking is not enough and naming one thing a tester does instead, which supplies facts on the topic and closes the thought.

All materials for W.1.2 →

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This material is in the public domain (CC0) and may be copied, edited, and shared freely, without attribution. Updated 2026-09-04.

Objectives

Students will compare two jars that look alike and predict what each drop will leave behind.
Students will record and read a two-category class vote about which jars look clean.
Students will explain what a dried drop shows about something hidden in clear water.

Vocabulary

Key words: clear, dissolve, evidence, test

Teacher overview

The fictional Mottlebeck Creek runs past the school fence, and a tester who works on that creek cannot decide anything by looking, which is the idea this lesson puts in front of first graders. Two jars sit side by side and look exactly alike, one holding plain tap water and one holding water with salt stirred in until it vanished, and a third cloudy jar of soil water stands nearby only as a reference point for what dirty water looks like. The lesson turns on a single piece of physical evidence: one drop from each jar is dried on dark paper, and the paper shows what the eye could not. The plain drop leaves nothing, the soil drop leaves a speck, and the clear salt drop leaves a white ring. The misconception being corrected is the everyday rule that clear means clean, which is a reasonable guide at a drinking fountain yet not a reliable one at a creek. Once the white ring has appeared on the paper, the class has a reason to check water by something other than looking. Tell the class at the start that nobody tastes or drinks from any jar, since a real tester never checks a sample with a mouth.

Procedure

Hook (5 min): Hold up the two clear jars, one in each hand, and ask the class which one they would call clean. Then set the cloudy soil jar beside them and take a show of hands for all three jars in turn, recording the counts on a two-column chart headed Clean and Not Clean. Say nothing yet about what is inside any jar.

Setting up the drop test (10 min): Explain that looking is one way to check water and that the class will now add a second way. Use the dropper to place one drop from each jar on its own labeled square of dark paper, keeping the squares apart, and set them in a sunny window or under a lamp. Ask students to predict aloud what each square will look like once the water is gone, and write two or three predictions on the board.

Building the prediction (12 min): While the drops dry, groups handle the sealed jars, hold them up to the light, tip them gently, and try to find any difference at all between the two clear ones. Ask each group to commit to a prediction in writing: same or different, and what they expect to see on each square. Circulate and press groups to say what evidence they are using rather than which jar looks nicer.

Reveal and formative check (5 min): Pass the three dried squares along the rows so every student sees the blank one, the brown speck, and the white ring. As the check for understanding, ask each student to name the square that surprised them and say why. If most students cannot point to the white ring as the reason Jar 3 was not clean, hold the ring beside the still-clear jar and ask where the ring came from before students start the handout.

Independent practice (13 min): Students work the numbered questions on the Student Handout, which carries the jar contents and the dried-drop results. Item 5 sends students back to the class vote chart from the hook, so keep that chart posted where everyone can read it.

The Dried Drop Test at Mottlebeck Creek: A Grade 1 Lesson — Grade 1 Science

Name: ____________________________ Date: ______________

Student Handout

Room 3 had three jars. Two of them looked the same. Then one drop from each jar dried on dark paper. Here is what the class saw.

Jar	What is in it	How it looked	What the dry drop left
Jar 1	tap water	clear	nothing
Jar 2	tap water and garden soil	brown and cloudy	a brown speck
Jar 3	tap water and salt	clear	a white ring

Which two jars looked the same before the test?
What did the drop from Jar 1 leave on the paper?
What did the drop from Jar 3 leave on the paper?
Jar 1 and Jar 3 looked the same. Tell what the dried drops showed about them.
Look at the class vote chart. How many more classmates called Jar 3 clean than called Jar 2 clean?
The drops are gone from the paper now. Tell where that water went.
Tell why looking at water is not enough to know what is in it.
Write one sentence. Tell one thing a water tester could do besides look at the water.

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

Answer Key

Answer: Jar 1 and Jar 3.
Both are listed as clear, even though only Jar 1 is plain tap water.
Answer: Nothing.
The tap water dried away and left the paper square blank.
Answer: A white ring.
The salt stayed behind on the paper after the water was gone.
Answer: They are not the same inside.
Jar 1 left a blank square and Jar 3 left a white ring, so Jar 3 was holding something that could not be seen in the jar.
Answer: Accept the number the class chart actually shows, checked against the two vote counts.
Students should subtract the Jar 2 count from the Jar 3 count and be able to point to both numbers on the posted chart.
Answer: Into the air.
The water left the paper and went into the room as vapor, which is why only the salt and the soil speck were left behind.
Answer: Accept any answer saying some things do not show.
Sample response: some things mix into water so well that they disappear from sight, so a jar can look clear and still hold something.
Answer: Accept any reasonable test.
Sample response: a water tester can dry a drop and look at what is left, or use a test strip that changes color.

Differentiation

Support

Give these students a two-picture card, one blank square and one square with a ring drawn on it, and let them answer items 2 through 4 by matching rather than writing. Read items 6 and 7 aloud and let students answer by pointing at the real dried squares before attempting any writing.

Extension

Ask students to plan a fourth jar that would fool the class, name what they would stir into it, and predict what its dried drop would show. Students can also test whether a coffee filter takes the brown out of Jar 2 and whether the same filter changes Jar 3 at all, then explain why the two jars behave differently.

ELL supports

Pre-teach "clear," "dissolve," "evidence," and "test" while stirring salt into a glass of water so students watch the word happen in front of them. Provide the sentence frames "Jar 1 and Jar 3 both looked ___" and "Jar 3 had ___ in it because ___," and accept oral answers or labeled drawings of the three dried squares.

Extensions

Repeat the drop test with tap water from the classroom sink and with water from a puddle outside that an adult collects in a lidded jar, and post the two dried squares beside the first three. Ask students to predict what the puddle drop will leave behind before it dries; finding out what a water sample holds is the work a water quality technician does for a living.