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Science activity

Pollution Solution

See how pollution makes water dirty and learn why we need to keep our water clean! Make dirty water and then try to clean it using a homemade filter.

Hands OnAbout 20 minutesScreen-freeParent help expected

Materials and setup

How this changes by age

Pre-K (ages 3–4)

See how pollution makes water dirty and learn why we need to keep our water clean! Make dirty water and then try to clean it using a homemade filter.

Difficulty 1 of 3

Steps

  1. Fill a clear jar with clean water. 'This is clean water — animals and people need it to live!'
  2. Now pollute it: add dirt, small pieces of paper, cooking oil, and food coloring. 'Oh no! This is what pollution looks like!'
  3. Talk about where pollution comes from: trash thrown on the ground, oil from cars, chemicals poured down drains.
  4. Try to clean it: pour the dirty water through a paper towel or coffee filter. Did it help?
  5. Look at the water: it is cleaner but not perfectly clean. 'It is much easier to keep water clean than to clean it after it gets dirty!'
  6. Tell a grown-up one thing that surprised you.

Learning objectives

  • Understand that pollution makes water dirty and unsafe
  • Observe that filtering removes some pollutants but not all
  • Recognize that preventing pollution is better than cleaning it up

Kindergarten (ages 5–6)

Model different types of pollution and design cleanup methods. Build a water filter and test how well it removes pollutants. Brainstorm ways to prevent pollution.

Difficulty 2 of 3

Steps

  1. Create 3 types of polluted water: (1) Soil and sediment (shake dirt in water), (2) Oil spill (add cooking oil), (3) Chemical waste (add food coloring and vinegar).
  2. Try to clean each type: for sediment, use a coffee filter. For oil, try paper towels or cotton balls. For chemical, try filtering — does it work?
  3. Build a better filter: layer cotton balls, sand, gravel, and a coffee filter in a cut plastic bottle (upside down). Pour dirty water through.
  4. Compare: which type of pollution was easiest to clean? Which was hardest? (Chemical pollution is very hard!)
  5. Brainstorm 5 ways you can help prevent pollution: pick up trash, don't pour things down drains, use less plastic, etc.
  6. Draw a poster showing 'Pollution Problems and Solutions.'
  7. Tell a grown-up one thing that surprised you.

Learning objectives

  • Identify different types of water pollution and their sources
  • Build and test a water filtration system
  • Brainstorm practical pollution prevention strategies

Early elementary (ages 6–8)

Investigate water and air pollution scientifically: model pollution effects on ecosystems, engineer filtration solutions, measure pollution levels, and create a community action plan.

Difficulty 2 of 3

Steps

  1. Research types of pollution: water (sewage, chemicals, plastics, oil), air (exhaust, factory emissions, smog), and soil (pesticides, heavy metals, landfill leaching). List 3 causes of each.
  2. Model pollution impact: set up 3 cups with plant seedlings. Water one with clean water, one with soapy water, and one with salty water. Observe plant health over a week. This models how chemical runoff affects plants.
  3. Engineer a multi-stage water filter: design a system using sand, gravel, activated charcoal, cotton, and coffee filters. Test it with polluted water (muddy, oily, colored). Measure clarity improvement.
  4. Investigate air pollution: tape white index cards coated with a thin layer of petroleum jelly in 4 locations (near a road, in a park, inside your house, in a garage). After 3 days, examine with a magnifying glass. Which collected the most particles?
  5. Research a real pollution event (Deepwater Horizon oil spill, Flint water crisis, or Great Smog of London). What happened? What were the effects? How was it addressed?
  6. Create a pollution action plan for your community: identify local pollution sources, propose solutions, and design an awareness poster.
  7. In one sentence, tell a parent or sibling what surprised you today.

Learning objectives

  • Model how different pollutants affect plant health and ecosystems
  • Engineer and evaluate multi-stage water filtration systems
  • Research real pollution events and propose evidence-based solutions

Upper elementary (ages 8–10)

Conduct a comprehensive environmental pollution study: measure local pollution indicators, engineer cleanup technologies, analyze the economics of pollution, and develop a persuasive environmental action campaign.

Difficulty 3 of 3

Steps

  1. Conduct a local water quality survey: collect water samples from 3-4 sources (tap, puddle, pond, stream). Test each for: clarity (can you read through it?), pH (using cabbage juice or pH strips), presence of sediment, and smell. Record all data.
  2. Engineer an advanced water purification system: research how municipal water treatment works (screening, settling, filtration, chlorination). Build a model treatment plant with multiple stages and measure improvement at each stage.
  3. Research microplastics: cut open a used tea bag or look at lint filter contents under magnification. Research where microplastics come from, where they end up, and why they are hard to remove from water.
  4. Investigate the economics of pollution: research how much does water treatment cost per gallon? How much did the Deepwater Horizon cleanup cost? Calculate the cost-benefit of pollution prevention vs cleanup.
  5. Study environmental justice: do all communities have equal access to clean water and air? Research which communities are disproportionately affected by pollution. Why does this happen?
  6. Create a persuasive environmental campaign: write a petition or letter to a local official about a specific pollution issue. Include data from your research, proposed solutions, and a cost-benefit analysis.
  7. In one sentence, tell a parent or sibling what surprised you today.

Learning objectives

  • Measure and evaluate local water quality using multiple indicators
  • Engineer and explain multi-stage water treatment processes
  • Analyze the social and economic dimensions of pollution and environmental justice

Safety and evidence note

Read the full activity before beginning. An adult should supervise tools, heat, food, outdoor work, movement, and experiments as appropriate. Completion records that the activity was done; the child’s explanation, work sample, photo, or demonstration is stronger evidence of learning than a completion check alone.

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