Download This Lesson: CAUTION: Chemicals
Brief Description: Students will use this lesson to understand cause and effect by seeing how chemicals can spread through soil as well as endanger plants and animals. They will conduct an experiment, observe, and draw conclusions as to why chemicals should not be the first choice when it comes to controlling pests.
Focus Areas: IPM, Science
Focus Skills: understanding cause and effect, conducting an experiment, observing, drawing conclusions
- To recognize that chemicals can spread through soil and water
- To understand that chemicals can endanger plants and animals
- To realize that the use of chemicals to control pests is not a wise FIRST choice
- What happens to the chemicals we use to control pests in our lawns and gardens?
- Why should we try to control pests using other IPM methods before using chemicals?
Chemicals, whether liquid or powder, used to control outdoor pests are easily moved by wind and water to places we never wanted them to go!
Chemicals are considered by many to be the most effective form of pest control. However, they pose a potential danger to every part of the Earth’s environment. The very ingredients that make various chemical products devastating to targeted pests are often highly toxic to non-targeted plants and animals as well. Powders and sprays don’t stay in a precise location when applied. Wind drift disperses the toxins to the surrounding area. When mixed with water, chemicals can seep into groundwater, affecting rivers, streams, and wells. Evaporation of these same products pollutes the air and contributes to the formation of acid rain.
Chemical controls are a part of IPM, but because of the potential dangers involved in their use, chemicals should never be the first line of defense in the war on pests.
chemical control – a product containing toxic ingredients used to control pests
dilute – to make something weaker by mixing it with other materials
herbicide – a chemical used to control weeds
hypothesize – to make a guess based on what you have observed
insecticide – a chemical used to kill insect pests
pesticide – a chemical used to control pests
pollution – something that damages the natural environment
seep – to slowly leak through from one place to another
toxic – something that hurts plants, animals, and our environment
Time: two 20-minute sessions, plus 2 to 3 minutes per day to observe plants
Group size: 2 to 25 participants
Space: a classroom
- paper cups (2 per individual or team)
- white plastic plates
- soil (enough to fill paper cups 1/2 full)
- red food coloring in a clear container
- blue food coloring in a clear container
- 3 liters of water
- measuring cup
- celery stalks
- white carnations
- Izzy puppet *
* single copy provided
1. Put three holes in the bottom of each cup.
2. Fill enough cups (for teams or individuals) 1/2 full with soil.
3. Put each cup on a plastic plate.
4. Fill remaining cups with water (1/2 full).
5. Prepare containers with food coloring and clear water.
6. Purchase celery stalks with leaves.
7. Place celery stalks in cups 1/2 filled with clear water.
8. Obtain carnations (1 per team of 3 or 4).
1. Izzy calls the children’s attention to the celery stalks in the water-filled cups and asks why the celery is in water. (Plants need water to live.)
2. Izzy shows the children the container of red food coloring and tells the children that the colored liquid is a pretend chemical control for pests that adults use to get rid of pests in their yards and gardens.
3. Izzy asks why adults use chemicals in their yards and gardens to get rid of pests. (Chemicals work well to kill pests.)
4. Izzy tells the children that the celery represents a weed pest and invites them to put some pretend weed killer in their cup.
5. The children add a drop of food coloring to their cup and set the cup aside.
1. The children observe what happens to the celery stalk over the next few days. (The colored water will be taken up by the celery stalk and show in the leaves.)
2. Izzy discusses with the group what will happen to these poisoned weeds. (They will die.)
3. Add more water, a new celery stalk, and a carnation to each cup.
a. Izzy explains that the carnations are not weeds, but rather plants that are wanted in the yard or garden.
b. Izzy explains that adding extra water diluted (weakened) the toxic herbicide and asks the children to hypothesize what will happen to the carnation.
4. The children observe the celery and carnations over the next few days. (The carnation as well as the celery will show signs of absorbing the food coloring.)
5. Izzy asks the children what might happen if bunnies or deer ate these plants. (They might get sick, too!)
6. Izzy discusses why adults might not want the herbicides to be absorbed by their flowers and vegetables. (The poison will make these plants sick, and if people eat them without washing them well first, they could get sick too!)
7. Izzy asks the children why using chemicals to kill animal and plant pests in their yards and gardens might not be the wisest choice. (Chemicals that kill pests can also hurt plants and animals that are wanted in the yard or garden.)
1. Izzy asks the children if lawns and gardens are planted in just water. (no)
a. Izzy asks a volunteer to explain how lawns and gardens are REALLY planted. (in dirt and then watered)
b. Izzy polls the group to determine if they think the soil (dirt) will protect the plants from absorbing (drinking) the chemicals. Record the results of this poll.
2. Distribute to teams the plastic cups, filled with soil and with holes in the bottom.
3. Display the chemical (food coloring) and add it to the dirt in each cup. (or to individuals)
4. Have the children place their cups on a plastic plate.
5. Have the children water their soil.
6. Check the cups and plates at the end of the day. (The water in the plates should be tinted with the chemical control.)
7. Izzy explains that the water that seeped through the soil is now polluted and will mix with rain, underground water, and streams! It will dilute, but it won’t go away.
8. Izzy helps the children form a generalization about the dangers of using chemical controls to stop pests. (Chemicals that destroy pests can also harm plants and animals that aren’t pests!)
Correlations to State of Maine Learning Results: Parameters for Essential Instruction
ELA = English Language Arts, HE/PE = Health Education and Physical Education, MA = Mathematics, SCI = Science, SS = Social Studies, VPA = Visual and Performing Arts
** Alignment possible only if lesson extension is done
Maine Learning Results
Common Core Standards for English and Mathematics
ELA – B. Writing
**B3. Students write to inform an audience on a specific topic.
a. Write brief descriptions of objects, people, places, or events.
b. Record and share, in writing, information that has been gathered.
** Extension: Students write about their observations of the carnation activity.
E1. Students use early active listening skills.
MATH – B. Data
**B2. Students read, construct, and interpret picture graphs.
** Extension: Students construct a picture graph based on the polling results.
SCI – B. Skills & Traits of Scientific Inquiry & Tech. Design
B1. Students conduct and communicate results of simple Investigations.
a. Ask questions and make observations about objects organisms, and events in the environment.
b. Safely conduct simple investigations to answer questions.
**E3. Students describe parts and wholes of living things, their basic needs, and the structures and processes that help them stay alive.
b. List the basic things that most organisms need to survive.
**Extension: Have class make list of things needed for survival.
ELA – Speaking & Listening
2. Confirm understanding of a text read aloud or information presented orally or through other media by asking and answering questions about key details and requesting clarification if something is not understood
2. Ask and answer questions about key details in a text read aloud or information presented orally or through other media.
2. Recount or describe key ideas or details from a text read aloud or information presented orally or through other media
MA – Grade 2: Measurement & Data (partial)