Lesson Plan #4: Chemicals and the environment

Learning objective

The pupils will get to know the term “environmental toxin”. They will understand that toxic chemicals ending up in the environment can either cause an immediate or a long-term damage. Also they will be familiar with the Environmental hazard pictogram and how to handle and dispose products with the pictogram on the label in a correct manner.


4th to 6th grade (approximately 10-12 years old)


Two lessons: 90 minutes

Introduction to environmental toxins

  • Environmental toxins are chemicals that can be toxic to living organisms.
  • Some environmental toxins, can harm both animals and plants if they end up in the nature. Well-known examples are lead and mercury compounds e.g. from mining, pesticides used in agriculture and certain chemicals used for treating ships to prevent growth of algae and other living organisms on the hull of the ships, but there are many more.
  • Chemicals in household products are not usually thought of as environmental toxins. Yet some of the products can also contain chemicals that may be hazardous to the environment.

Make presumptions about sources, environmental damage and the tree and the dead fish.

In this session the pupils are supposed to make presumptions about chemicals and the environment. Their presumptions will be tested in Hanna’s House later on. There are no correct answers to the questions. The important thing is to get the pupils to reflect and discuss.

  • Question 1: From which sources do you think that the man-made harmful chemicals can end up in the environment
    Answers could be accidents and spills, industrial wastewater sewage, air pollution from chimneys and traffic, illegal dumping of barrels with chemicals, household chemicals. Write the pupils answers on the board.
  • Question 2: What happens with the chemicals once they are released into the environment?
    Answers could be damage to food chains and eco systems, air pollution, long-range transport to e.g. the Arctic, water pollution, sick or dead animals. Write the pupils answers on the board.
  • Question 3: One of the nine hazard pictograms shows a tree and a dead fish. What do you think that this pictogram mean?
    Answers could be oil spill, water pollution, dangerous to nature, dead fish. Write the pupils answers on the board.
  • Question 4: The pictogram is found on some of the products you might have at home. What kind of products?
    Tell them that the products are often found in the kitchen or in the garage. Let the pupils work in pairs for 10 minutes.
    Write the pupils suggestions on the board. Let the pupils explain why they think that the products they suggested have the Environmental hazard pictogram on the label.

Research and reflection: Read the article “Chemicals and the environment”

  • Ask the pupils to read the article “Chemicals and the environment” on the website hannashouse.com. You can also print hand-outs of the article. The pupils should be able to read the article in 10-15 minutes. Do it in class or as homework.
  • Let the pupils discuss the article in pairs and write down any questions.

Let the pupils ask clarifying questions about the article in class.

  • Discussion in class: The environmental hazardous chemicals can either stay in the food chain for a long time or they can cause immediate damage once they are released into the environment. Describe the difference between the two.
  • Discussion in class: What is a food chain? Try to make up a food chain on the board and describe what happens when a chemical build up in the food chain.

Testing presumptions: Visit Hanna’s House

  • Go through the 9 situations in Hanna’s House and find the products with the Environmental hazard pictogram on the label.
  • Take notes about the different products:
    • What is the correct way to handle the products?
    • What should you never do with remnants from products labelled with the Environmental hazard pictogram?
    • What other products besides ant poison and wood preservative is it likely to find the Environmental hazard pictogram on?
  • In class: Walk through the pupils’ answers from the previous presumption session. Fill in with new insights from the Hanna’s House session.

Extend the lesson plan: Make your own environmental hazard quiz

Make your own multiple-choice quiz with 5-10 questions designed in the same way as the situations in Hanna’s House: One question with three options. One of the three answers is the correct one.

In order to design the quiz the pupils will have to use their new knowledge and find more information in Hanna’s House.

Let the pupils work together in small groups. Hand out 10 index cards.

Write the question and the options on one side. Display the correct answer on the flip side.

Some examples could be:

There are nine hazard pictograms. What’s on the pictogram Environmental hazard?

  1. A super tanker spilling a pool of black oil in the ocean
  2. A tree and a dead fish
  3. Three dead polar bears

 On which products is it likely to find the Environmental hazard pictogram on the label?

  1. Grill lighter fluid
  2. Detergents
  3. Wood preservatives

What is the correct way to dispose products with the Environmental hazard pictogram on the label? 

  1. Pour it into the sink. It will clean the drain.
  2. Use the remnants of the product to water the plants in the garden. It’s a kind of fertilizer.
  3. Always deliver the remnants at the waste management centre.

The pupils can use the quiz to test their friends or their parent’s knowledge about the Environmental hazard pictogram.