Lesson 2: Testing our Ideas
(45 minutes, then 2-4 weeks of growing and observing)
Key question
- Can corn grow with different types of light sources or NO light?
Learning Objectives
- The children will plan and conduct an investigation to test environmental factors on corn (example: different types of light).
Materials
Suggestion: gather materials after your child has decided what light sources they would like to test for their experiment. Ideas are provided below.
- Corn seeds
- Different types of light: grow light, lamp, box with holes in it, clear tote to put over the plant, etc.
- Measuring Spoon
- Planting container
- Planning and Recording Sheets (page S1) or Science Journal
- Labels or markers
Guided Teaching
Introduction
Introduce the topic and ask for prior knowledge with questions such as:
- “What do we think that plants need to live and grow?”
- Farmers need to consider such needs and they need to provide the best conditions for their plants to live and grow.
- “How can we investigate the needs of corn plants?” (For instance, we know plants need sunlight to grow. However, can plants grow when other types of light or no light are given?)
Become a Scientist
- Ask the question, what is a scientist.
- Let your children share their ideas about what they think of when they think of a scientist.
- Scientist are found in a lot of jobs and places around the world. Without scientists we would not have the food, medicine, technology or simple items we use every days.
What is an experiment?
- Ask your children what is an experiment? Let your children share ideas about what they think an experiment is.
- An experiment is when an idea is tested to see if it will work. Experiments have been used for many years to test ideas or to see why things in the world work as they do.
- Example would be Isaac Newton. He did experiments to explain gravity. Norman Borlaug created a new type of wheat that saved one billion people from starvation.
Scientific Method
- When scientist conduct an experiment, they use the “scientific method.” This is a list of steps scientist use to make sure they do their experiment in the correct way. This explanation leads into the start of the children creating their own method.
Scientific Method Step 1: Ask a Question
- Each experiment starts out by asking a question you want to test out.
- For this experiment the question is: Do different types of light affect plant growth?
- Ask children if they think light affects plant growth. (Write down responses to keep for future discussion)
- Ask children to come up with a list of different types of light they would like to use. At this time, your child will need to pick what type of light, or lack of, they would like to use for their experiment. Examples of light sources: box with holes, lamp, grow light, clear tote to put over the plant, indirect sunlight, closest or cabinet for no light, etc.
Scientific Method Step 2: Form a Hypothesis
- Make a prediction about how well your corn will grow with these different light sources. Hand out the Planning and Recording Sheet or have your children record the appropriate information in a journal.
- Children will write down what light source they want to test and then write down their hypothesis about how well their corn will grow. If you have multiple children have them each choose a different light source.
- Discuss the experiment and the importance of having a control plant and experimental plants.
- The control plant will use the same type of soil, the same pots, the same amount of corn seeds, the same amounts of water each day, and the prescribed amount of light as all other plants. During this planning process. It is important to state that in order for this to be a true experiment, all steps of the experiment must be the same except for what you are testing, which is the light source. You as the educator can oversee the control plant or assist the children in taking care of all plants, including the control plant, to make sure each plant is taken care of the same except for light.
- The experimental plants will have the same soil, pots, seeds and water as the control plant. The variable for the experimental plants is light.
Set up Experiment-Plant Corn
- Following your child’s plans, provide them the materials needed for their investigation(planting pots, soil, measuring spoons for water, items to block light, etc.) and tell them how much time they will have (consider 2-4 weeks for seeds to germinate and grow).
- Watch this video of Farmer Bill who provides suggestions on best way to set up the experiment and plant the corn. https://bit.ly/3U0DLcB
- After the children have planted their corn, review the variables between the control plant and experiment plants.
- Decide who is going to plant the control plant and follow the same procedure.
Start the Investigation
Water the plants with the amount of water for optimal growing conditions. Farmer Bill made suggestions in his video.
- Be sure to label the containers to identify the light source.
- Have the children set their corn pots in their lighting conditions. Remind children that this is the experimental part, this is what you are testing. Can corn grow with different types of light?
- On the Planning and Recording Sheet or in a journal have the children draw a picture of what their seed looks like now, and what they think it will look like at the end of the investigation.
- Put the “control” plant in full sunlight. The corn plant will mimic what a corn plant gets in a farm field- full sunlight. During the next several weeks have the children compare their plants to the control plant.
- (If it is cold outside keep in mind that temperature also impacts plant growth. Putting plant in a window for full sunlight but where it may be colder during winter months may slow down growth.
- Once planted, emergence of leaves above the soil will take approximately 5-7 days.
Planting Directions and Optional Growing Conditions
- Fill each pot with unpacked soil to top of pot. Around 1 1/2 cups. Pack soil lightly until each pot with soil looks similar.
- Add 5 tablespoons of water.
- Plant 2-3 seeds in each pot approximately ½ to 1 inch deep.
- Plant the control plant in or near a window with access to light.
- Try to place all plants in areas with similar temperatures.
- Touch soil of every pot daily. If it is moist, don’t add water. If it is dry, add two tablespoons. (Note: based on light conditions, some may need less water to keep moisture the same in to all pots.)
Scientific Method Step 4: Observe and Record
- Have your children water their plants as directed with measuring spoons over the next 7-28 days making sure they touch their soil daily and add water only when it feels dry.
- Provide observation times during the days/weeks for the children to observe (draw) and record (describe) the progress (or lack of progress) of their plants on their Planning and Recording Sheet or in their journal over 7-28 days.
- As you start to see the plants grow, watch the “Experiment Check-in” video with Farmer Bill.
Early Elementary Activity
Writing
- In their science journal, have your child write a conclusion at the end of week 1. Children can write about their prediction and what was correct or different since the beginning of the experiment. This would be a nice way to do a midway check through of the experiment.
Art
- After week 1, have your children draw a picture of the control plant. Next to it, draw a picture of the “other types of light source” plants. Discuss the similarities and differences that are observed.
Upper Elementary Activity
Writing
- In their science journal, have your child write a conclusion at the end of week 1. Children can write about their prediction and what was correct or different since the beginning of the experiment. This would be a nice way to do a midway check through of the experiment.
Art
- After week 1, have your children draw a picture of the control plant. Next to it, draw a picture of the “other types of light source” plants. Label the two plants with the plants part names. Example, stem, leaves, etc. Then under the drawings, create a Venn Diagram to show the similarities and differences that are being observed.