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This is the second of five lessons in the geoengineering series. In this activity students will explore how the number of cloud condensing nuclei (small aerosol particles for the moisture to condense upon) will alter the brightness of a cloud.
- Grade level
- Grades 6-12 (ages 11-18)
- Materials
- 10 resources available
- Questions?
- Contact the lesson team
Needs review before publishing
- These captions were made by machine transcription and corrected by Claude, but no person has checked them yet. Watch the video with cloud-in-a-bottle_setup-video.srt and fix any errors (corrections can go in tools/video/fixes/cloud-in-a-bottle.json; rerun tools/prepare_video.py with --captions-only), then remove this flag.
- These captions were made by machine transcription and corrected by Claude, but no person has checked them yet. Watch the video with cloud-in-a-bottle_low-aerosol-video.srt and fix any errors (corrections can go in tools/video/fixes/cloud-in-a-bottle.json; rerun tools/prepare_video.py with --captions-only), then remove this flag.
- These captions were made by machine transcription and corrected by Claude, but no person has checked them yet. Watch the video with cloud-in-a-bottle_high-aerosol-video.srt and fix any errors (corrections can go in tools/video/fixes/cloud-in-a-bottle.json; rerun tools/prepare_video.py with --captions-only), then remove this flag.
- Claude drafted the Global Connections section, and the global competence and UNESCO SDG 13 entries under Standards, from the lesson materials. Review and edit them.
Overview
Objectives
By participating fully in this activity, students will:
- Learn about a specific climate engineering technology (Marine Cloud Brightening)
- Learn how a cloud is formed and how a cloud’s input components can be modified to change its brightness
Grade Level
Grades 6-12
Standards
These are Next Generation Science Standards (NGSS) performance expectations.
- MS-ETS1-3 Engineering Design. Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success.
- MS-ETS1-4 Engineering Design. Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.
- HS-ESS3-4 Earth and Human Activity. Evaluate or refine a technological solution that reduces impacts of human activities on natural systems.
- HS-ETS1-2 Engineering Design. Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering.
This lesson also supports these international frameworks:
- Global competence (Asia Society and OECD): Investigate the world
- UNESCO learning objectives for SDG 13 (Climate Action):
- Cognitive 5: prevention, mitigation and adaptation strategies
United Nations Sustainable Development Goals
- SD Goal 4: Quality Education: Ensure inclusive and equitable quality education and promote lifelong learning opportunities for all.
- SD Goal 9: Industry, Innovation, and Infrastructure: Build resilient infrastructure, promote inclusive and sustainable industrialization, and foster innovation.
- SD Goal 13: Climate Action: Take urgent action to combat climate change and its impacts.
Materials Required
- Marine cloud brightening worksheet
- Excel calculator spreadsheet (optional)
- Clean 1-liter bottles
- Aerosol spray (hair spray)
- Graduated cylinder with a precision of 10ml
- Lux meter
- Flashlight (medium to large size)
- Dark non-reflective background (curtain, sheet, cardboard painted black or covered in black construction paper)
- 500 ml water
- Fizz keeper or hand air pump (with #3 hard rubber stopper and tire valve plug)
Material purchasing list with the links to purchase are provided under teacher resources.
Learning Sequence
Lesson Plan Introduction
This activity explores how aerosols affect the brightness of the cloud by creating a cloud in a bottle and measuring the brightness of the cloud using a flashlight and a lux meter to measure the reflected light. The brightness of the cloud is manipulated by changing how much aerosol hairspray is added to the bottle.
Note that this activity can be tricky. We have experimented with groups of students conducting this experiment with mixed success but frequently fall back on either demonstration-experiment or collective experimental design to complete the experiment itself.
Activity Details
Activity setup
- The light source, lux meter, bottle, and black background should be in a straight line with relative positions recorded.
- With the flashlight and lux meter turned on, add hairspray to the bottle, compress the bottle, and rapidly decompress to form a cloud. Measure the brightness of the cloud.
- Refer to experiment setup video in the teacher for more details on the experimental setup.
- Students complete the pre-Experiment One questions, 1-2, on the worksheet. Review questions and answers with students.
- Review the Research Question (PPT slides 7-9) and have students hypothesize whether the clouds will be brighter with more aerosols.
- Run through the experiment design, materials, and methods before beginning the trials
Experiment One – Low Aerosol Environment
- Refer to the low-aerosol experiment video in the resources for more details.
- The low aerosol experiment uses a small amount of water (~20ml) and a low number of sprays of hairspray (e.g., 3).
- Use the Fizz Keeper or bicycle pump to pressurize the bottle while keeping track of the number of squeezes/pumps.
- With all components turned on and in a line, rapidly depressurize the bottle so a cloud forms.
- Immediately read and record the value on the lux meter.
- Wait for the cloud to completely dissipate and read the lux meter again.
- Repeat the experiment for multiple trials (e.g., ten times). Use the Excel calculator to find averages and standard deviations if desired.
Experiment Two – High Aerosol Environment
- Complete the same experiment with a high number of sprays of hairspray (e.g., 10 sprays) to create a high number of aerosol particles.
- Refer to the lesson plan and experiment video demonstration for more details on conducting this experiment.
Data interpretation
- After the experiments let students complete the data table and remaining questions from the worksheet
- OPTIONAL – Use the Excel spreadsheet to calculate the mean, standard deviation and two tailed t-test for significance.
- The difference between the lux meter reading with and without the cloud will be larger for the high-aerosol versus low-aerosol experiment
Conclusion
Students manipulate the amount of hairspray added to a 1-liter bottle to change the brightness of a cloud formed through compression and rapid decompression of the bottle. The brightness of the cloud is measured with a lux meter measuring the reflected light from a flashlight.
We have experimented with using different sources of cloud nuclei particles (e.g., salt water) as well as using live data logging (e.g., Vernier light meters), but have not yet identified a suitable methodology for this kind of addition to the activity.
Global Connections
Needs review: Claude drafted the Global Connections section, and the global competence and UNESCO SDG 13 entries under Standards, from the lesson materials. Review and edit them.
Start where you teach
Start by asking students to describe the clouds, fog, haze or smoke they see where they live, and what makes some clouds look brighter than others.
Bring in other perspectives
Discuss where marine cloud brightening would actually be done, over particular oceans and near some coasts but not others, and who lives downwind, so students see how a classroom experiment scales up to decisions that affect other places.
Share beyond the classroom
Classes running the experiment can share their data with another class and compare results from different bottles, aerosols and light conditions.
Use local materials
The materials purchase list links to sellers in the U.S. Any equivalent works: a clean 1-liter plastic bottle, a rubber stopper fitted with a bicycle tire valve, a hand pump, hairspray, a flashlight, and a light meter or a free light-meter app on a phone.
Lesson materials
Download the files below to teach this lesson. PDFs are accessible versions; PowerPoint and Excel files can be edited for your class.
Teacher resources
Full lesson plan
Lesson slides
Experiment setup video demonstration
Needs review: These captions were made by machine transcription and corrected by Claude, but no person has checked them yet. Watch the video with cloud-in-a-bottle_setup-video.srt and fix any errors (corrections can go in tools/video/fixes/cloud-in-a-bottle.json; rerun tools/prepare_video.py with --captions-only), then remove this flag.
Narrated demonstration. Download the MP4 video and its captions to show it without an internet connection.
Low-aerosol experiment video demonstration
Needs review: These captions were made by machine transcription and corrected by Claude, but no person has checked them yet. Watch the video with cloud-in-a-bottle_low-aerosol-video.srt and fix any errors (corrections can go in tools/video/fixes/cloud-in-a-bottle.json; rerun tools/prepare_video.py with --captions-only), then remove this flag.
Narrated demonstration. Download the MP4 video and its captions to show it without an internet connection.
High-aerosol experiment video demonstration
Needs review: These captions were made by machine transcription and corrected by Claude, but no person has checked them yet. Watch the video with cloud-in-a-bottle_high-aerosol-video.srt and fix any errors (corrections can go in tools/video/fixes/cloud-in-a-bottle.json; rerun tools/prepare_video.py with --captions-only), then remove this flag.
Narrated demonstration. Download the MP4 video and its captions to show it without an internet connection.
Worksheet with answers
Data spreadsheet with sample data
Materials purchase list
Student resources
Student worksheet
Data spreadsheet
Related lessons
- Introduction to Marine Cloud Brightening: the science of marine cloud brightening, including ship tracks and open research questions
Credit and contact
Credit
Created by the Indiana University Climate Engineering team: Paul Goddard, Ben Kravitz, and Adam Scribner.
Contact
Questions about this lesson, or need a file in another format? Contact:
- Paul Goddard – pgoddard@iu.edu
- Ben Kravitz – bkravitz@iu.edu
- Adam Scribner – jascrib@iu.edu