Activity 1: Needs of a Plant

1. Ask the students if they have ever taken care of a plant. If they have, ask them to describe what they did to care for their plant.
2. Ask the students, "What are the basic needs of plants?" (nutrients, water, air, and light) Use the Needs of a Plant PowerPoint Slides to introduce the four basic needs of a plant.
3. Distribute the What Do Plants Need to Grow? grid and cards to each student.
4. Instruct the students to cut out the cards and place them on the grid in the column under the plant necessity described and the row number indicated on the card.
5. After the students have arranged all of their cards, review the PowerPoint to check that the cards have been properly placed on the grid.
6. Once the students are satisfied with the arrangement of their cards, instruct them to tape the cards together exactly how they are placed on the grid, being careful not to tape them to the grid below.
7. When all of the card pieces have been taped together, ask the students to turn the cards over to reveal the diagram of the needs of a plant. Using the information from the PowerPoint and the cards, discuss the basic needs of a plant.

Activity 2: Needs of a Fish

1. Ask the students, "What do you need to survive?" (food, water, air, and shelter) Ask the students if they think fish have the same or different needs. Discuss their responses and guide them to the understanding that fish have the same basic needs as humans.
2. Organize the students into small groups to play the game "Go Fishing." This game is played like the game "Memory," but instead of trying to find exact matches, the teams will match questions about the basic needs of fish with the correct answers. Provide each group with a set of Go Fishing Cards, paper clips, a pencil, a piece of string, and a magnet. The cards should be printed with the fish picture on one side and the words on the other.
3. Instruct the groups to make their fishing pole by tying one end of the string to a pencil and the other end to a magnet. They should attach a paper clip to each card and spread them out with the fish images facing up.
4. Split the groups into two teams. The teams should take turns "catching" two fish cards with the fishing pole. If their fish cards match, they keep the cards and take an extra turn. The cards match if one card correctly answers the other card's question. After all of the cards have been correctly matched, the team with the most matches wins.
5. After the game, review the basic needs of a fish by discussing the questions from the cards with the class.

Activity 3: Design a Classroom Aquaponics System

1. View the video What is Aquaponics? to explore an urban aquaponics farm. Explain to the students that this farm uses a large-scale aquaponics system to produce fish and vegetables. As a class, they will be assembling a small-scale system that meets the needs of fish and plants. 
2. Project The Aquaponics Cycle diagram onto a large screen. Use the following information to discuss the cycle with the students:
   • Fish produce waste. The fish waste contains ammonia, which will poison the fish unless it is filtered out. In an aquaponics system, the water from the fish tank, including the fish waste, is pulled up to the plant trays through a pump.
   • Microbes convert waste into nutrients. The ammonia in the fish waste that is present in the water being pumped into the plant trays is quickly converted into nitrite and nitrate by the bacteria naturally present in the trays.
   • Plants filter the water that returns to the fish. Nitrates and nitrites are beneficial nutrients that are absorbed by the plants. This process filters the water. The clean water is drained back into the tank, providing a fresh source of water for the fish.
3. Show the class the basic materials needed to assemble the classroom aquaponics system—two clear plastic containers, expanded clay pellets, water pump, tubing, grow light, fish cave, water, fish, and plants. Ask the students how they think the materials can be used to create an aquaponics system.
4. Arrange the students in small groups. Incorporating the materials shown, ask each group to design an aquaponics system that meets the needs of the fish and plants. Have the groups sketch their design and share their ideas with the class.
5. After the students share their ideas, use the Classroom Aquaponics System Assembly and Maintenance Guide instructions and the Classroom Aquaponics Instructional Video to assemble the system as a class. Compare the system from the guide with the class designs.
6. Pass out the Meeting Needs Activity Sheets to each student. Ask the students, "What are the basic needs of plants?" (Plants need nutrients, water, air, and light.) Instruct the students to fill in the "Plants Needs" columns of the activity sheet with one of the basic needs of a plant in each row.
7. Ask students if plants need water to come from rain, light to come from the sun, and nutrients to come from the soil. Discuss the concept that water, light, and nutrients can come from other sources.
8. Discuss and record in the "Meeting Plant Needs" column how plant needs are met in an aquaponics system. Nutrients come from the fish waste, water comes from the fish tank, air comes from the classroom, and light comes from the grow light.
9. Ask the students, "What are the basic needs of a fish?" (Fish need food, water, air, and shelter.) Instruct the students to fill in the "Fish Needs" column with one of the basic needs of a fish in each row.
10. Discuss and record in the "Meeting Fish Needs" column how fish needs are met in an aquaponics system. Clean water comes from water that is filtered by the plants and drained into the fish tank, air is present in the water, and shelter is provided by the rock cave in the fish tank. Point out that food for the fish is not provided within the aquaponics system and must be provided for the fish each day. All of the fish and plant needs are taken care of within the system with the exception of food for the fish.
11. Allow time each school day for students to feed the fish and gather, record, and interpret data in their science journals about the system's water quality, water temperature, fish behavior, and plant growth. Using the data gathered, make adjustments as necessary to maintain a balanced system.