Grade: Elementary
Subject: Science

#1396. Popcorn!

Science, level: Elementary
Posted Thu Nov 11 08:53:42 PST 1999 by Lisa Esposito (
The College of Saint Rose, Albany, NY
Materials Required: Fresh Popping corn, hot air popper, ruler, 3 identical clear containers, oil, data sheet
Activity Time: 45 minutes
Concepts Taught: Hyptheses, Measurement, Experimentation, Drawing Conclusions


Demographics: This lesson is designed for a heterogeneous tutorial group of four second-grade students. It should last approximately forty-five minutes.

Goals and Objectives:

a) Lesson Goals:
1. The students will form a hypothesis.
2. The students will carry out an experiment.
3. The students will explain their findings.
4. The students will be able to explain the experiment.

b) Lesson Objectives:
1. Given necessary information, the students will form a hypothesis about he experiment that is to take place.
2. Given the appropriate materials, the students will measure and pop three different batches of popcorn.
3. Given the above experiment, the students, in their own words, will describe what happened.
4. Given factual information on popcorn and why it pops, the students will be able to explain this idea in their own words.
5. Given this lesson, the students will eat their popcorn!

Rationale: According to the New York State Learning Standards for Mathematics, Science, and Technology, the students will demonstrate Standard One, substandard one under Scientific Inquiry which states, "The central purpose is to develop explanations of natural phenomena in a continuing, creating process" as they form a hypothesis. Additionally, students will demonstrate Standard Three, substandard five which states, "Students use provide a major link between the abstractions of mathematics and the real world in order to describe and compare objects and data" as they measure popcorn kernels before popping, and the volume after popping. Students, when explaining why popcorn pops and why it pops differently depending on its properties, will demonstrate Standard Four, substandard four which states that, "Energy exists in many forms, and when these forms change, energy is conserved." Lastly, as a result of the entire lesson, students will demonstrate Standard Seven, substandard two, relating to Interdisciplinary Problem Solving and Strategies.

*Note: If an oven is not available, the teacher may have to prepare #1-2 before hand.
1. Preheat the oven to 200 F. Spread out cup of popping corn in a single layer on a cookie sheet. Bake for two hours.
2. Put another cup of popping corn in an airtight container with one tablespoon of water. Shake the jar so that the water coats the seeds. Let the jar stand overnight and shake the jar every few hours to redistribute the water, if possible.
3. The following day...display the kernels and let the students observe. Ask them to form a hypothesis of what will happen to a) the "baked" kernels, the "water" kernels, and the "regular" kernels. Students should record their hypotheses on the attached data sheet.
4. Use a hot-air popper to pop the cup of dried corn (from the oven). Place the popped corn in a labeled 8-oz. cup. Pop the "water" kernels and place them in a separate labeled 8-oz. clear cup or container (identical to the other glass/container). Lastly, pop the kernels that were untreated (regular). Place those in an identical, labeled 8-oz. Cup or container.
5. There should now be three identical containers (clear) labeled "Baked", "Water", and "Regular."
6. Ask a volunteer to come up and measure (in centimeters) how much the container is filled. Record these answers on the blackboard as well as on the students' data sheets.
7. If all works well, the "water" kernels should have popped the best, the "baked" kernels the worst, and the "regular" kernels somewhere in between. Ask the students, "Can anyone explain why these three batches popped differently?" Accept answers and conduct appropriate discussions regarding those answers.
8. Tell the students, "Each popcorn kernel contains a certain amount of moisture. The amount of moisture that is inside the kernel will decide how big the kernel will be when popped."
9. Ask, which kernels that we used today had the most moisture in them?" Accept responses. Explain, "The kernels that we left in water overnight have the most moisture in them. Since they were sitting in water, they absorbed water, kind of like a sponge." Ask, "Can anyone guess which kernels had the least amount of moisture?" Accept responses. Explain, "The kernels that were baked in the oven had the least amount of moisture. When we baked them, the moisture was released and the heat dried them out. The kernels that we took right from the jar had the average amount of moisture in them."
10. Ask, "We understand now that there is moisture inside of the kernel. But...why does the kernel pop? Accept appropriate responses. Explain, "When the kernel is heated, the moisture inside becomes steam. Once this steam reaches a certain temperature (347 F) the seed coat, or skin, rips open and the inside of the kernel bubbles and becomes solid. Really, the kernel turns itself inside out, we could say."
11. Tell the students to write, in their own words, a simple conclusion from this experiment using the information that they learned.
12. Read The Popcorn Book by Tomie Paola and let the students eat the popcorn as they listen to the story.

Student Evaluation
A formative assessment will be determined through teacher questioning and teacher observation, as well as a completed data sheet with obvious effort. Also, the students' motivation/interest will be taken into consideration.
Teacher Evaluation
A teacher evaluation will be conducted by the teacher asking him/herself:
-Did I try my hardest to motivate the students?
-Did I encourage the students to form a hypothesis and conclusion?
-Did I explain the factual information in a clear and concise manner?

Materials Required:
-Three identical clear 8-oz. containers - Ruler
-FRESH popping corn kernels - Oven
-Hot air popper - Air-tight Jar
-Oil - Water
-Butter/salt if desired -Data Sheet (attached)

Bibliographies/Student Resources
New York State Education Department. Learning Standards for Mathematics, Science, and Technology. Albany, 1996.
de Paola, Tomie. The Popcorn Book Holiday House, New York: 1978.