Science Standard 5: Understand the structure and function of cells and organisms.
Benchmark # 1: Know the basic needs of plants and animals (e.g., air, water, nutrients, sunlight/food, space/shelter).

Science Standards 6: Understand relationships among organisms and their physical environment.
Benchmark # 1: Know that plants need certain resources for energy and growth (e.g., air, food, water and sunlight).

 

Science Standard 9: Understand the sources and properties of energy.
Benchmark # 1: Know that the Sun supplies heat and light to the Earth.

A two year study by NASA and the Associated Landscape Contractors of America has found common houseplants to be beneficial in reducing indoor pollution. Dr. Wolverton, a NASA scientist, recommends at least 1 houseplant for every 100 square feet of indoor space. For optimal cleansing of indoor pollution, 2- 4 medium sized plants are suggested. About a dozen varieties of indoor plants have helped reduce “Sick Building Syndrome.” People who suffer from this condition have symptoms of allergic reactions, headaches, fatigue, asthma, nervous system disorders, respiratory and sinus congestion. There are three major sources of indoor pollution: hermetically sealed buildings and heavily glued construction materials and furnishings; poor ventilation; and human emissions such as cosmetics and cigarette smoke. Specific varieties of indoor plants remove and absorb Volatile Organic Compounds (VOC’s) from the air around them. For a lists of specific plants see the Extensions section below.

Photosynthesis, an essential process to life on Earth, takes place mainly in the leaves of green plants. It is the process that provides us with food and allows us to maintain appropriate levels of oxygen within the atmosphere. Photosynthesis is a chemical process that changes carbon dioxide, water and nutrients/minerals into simple and complex sugars, using the energy from sunlight. The parts of a typical leaf include the upper and lower epidermis, the mesophyll, the vascular bundles, and the stomata. The upper and lower epidermal cells serve primarily as protection for the leaf. The stomata, holes located in the lower epidermis of leaves, also absorb pollutants in the air. Their main purpose is air exchange, absorbing the carbon dioxide and expelling oxygen as a byproduct. The vascular bundles in a leaf are part of the plant's transportation system, moving water and nutrients, up from the roots and around the plant as needed. The mesophyll cells have chloroplasts, which contain the chlorophyll that captures the sunlight, and this is where the process of photosynthesis takes place.

 

Kid’s Speak: Green plants make their own food. They use water, minerals and other good things found in soil, along with an invisible gas from the air, called carbon dioxide. The green plants soak up the water and minerals from the soil using their roots. The water and minerals move up into plants through tiny tubes that work something like the pipes in a house, letting them flow to the parts of the plants that need them. Animals, including people, breathe in oxygen from the air and exhale carbon dioxide, but too much carbon dioxide in the air is not good. Plants help by recycling it and using the carbon dioxide to make food. Scientists have found that houseplants also help clean harmful pollutants from the air we breathe.

The leaves are where most of the food making is done. The leaves have small holes on the back of them and the carbon dioxide enters the plants through these holes. Once everything is inside the plants, sunlight helps to change them into sugars. The plants use these sugars as food to help them to grow. Once the food is made the plants have oxygen left over that they don’t need so they release it into the air. Without plants we would have not have oxygen to breath. We call this food making process photosynthesis.

We spend over 90 % of our time indoors. According to the Environmental Protection Agency indoor air pollution (which causes allergic reactions and fatigue) is one of the top threats to public health.

1. teacher can create a large version of the in and out green plant diagram worksheet provided below explain the process of photosynthesis in simple terms. Label the top of the chart on the left hand side with the word IN. Continuing to use the left hand side of the chart, shade in the ground or add brown dots around the roots to indicate minerals and nutrients. Then add water as droplets of rain, or perhaps water dripping from a watering can. Finally draw a sketch of someone exhaling, or if you have reached the limits of your artistry, try blowing on the leaves of your diagram to demonstrate where the carbon dioxide is taken into the plant. To complete this part of the diagram draw the sun with rays to illustrate how sunlight activates the change process.

After Making the Green Plant Diagram:

Part 2 - Activity for Determining Number of Plants Needed to Best Filter Indoor Air:
- Explain to students that they will determine the number of houseplants needed to cleanse your classroom of indoor pollutants. Ask students how they can make this determination. Accept response that they will need to first measure size of room. Next students will calculate how many plants are needed to cleanse their classroom based on the rule of at least one plant for every 100 square feet of indoor space
- Using a yardstick, measure and record the dimensions of classroom.

- Use graph paper to represent the dimensions and shape of classroom. One space on the graph paper is equal to one square foot of classroom floor space. Draw a square foot on the board or provide a cut-out of a square foot to help students visualize and understand that unit of measure.
- Demonstrate on large graph paper how to count and mark off room representation on graph paper.
- Students can follow steps provided by teacher and mark off room representation on their own graph paper.
- Students will count and color 100 squares to represent one needed plant. Continue procedure using different colored crayons or markers until less than 100 squares remain.

• What is the least amount of plants needed to clean the air in our classroom?
• If we wanted to put 2 plants for every 100 square feet how many would we need?
• If we wanted to put 4 plants for every 100 square feet how many would we need?

• Remind students of formula to calculate area: length (in feet) x width (in feet) = area (in square feet).
• Divide area by 100 to determine the number of plants needed to best filter air.
• Discussion questions:
• What is the least amount of plants needed to clean the air in our classroom?
• If we wanted to put 2 plants for every 100 square feet how many would we need?
• If we wanted to put 4 plants for every 100 square feet how many would we need?

Fostering the new generation of environmental stewards.