• Seaweed is not a plant, but algae. It exists in three basic colors: green, brown and red. Seaweed is important to the waters of the world because it provides food for underwater animals and fish, as well as shelter for these creatures. Identification of the parts and functions of seaweed, testing the survival rates of different types of seaweed and investigating seaweed as an organic fertilizer to assist farmers will build student understanding about how seaweed functions.
  
  

Identify

• Like a plant, seaweed has distinctive parts that have specific functions. Students have the ability to gather information about seaweed parts, such as the holdfast, stripes blades, floats and the thallus as a means of understanding how seaweed functions in the water. In addition, students that participate in science projects involving seaweed can identify what keeps it alive in the water and how it assists in keeping other living things alive under the sea.
  
  

Survival

• Ocean Link indicates that seaweed must have water in order to survive. When seaweed is taken out of the water it will eventually dry up, although in some cases when seaweed is returned to the water it will re-hydrate and return to normal functioning. Science Clarified states that both freshwater and saltwater seaweed exist and some seaweeds are common to shallow waters, while others exist primarily in deep waters. If both of these factors are taken into consideration--the ability of seaweed to dry out and the varieties of seaweed--students can develop science projects aimed at determining if one factor is impacted by the other. For example, students can use three types of seaweed that have been gathered from their natural water habitat and lie the seaweed on dry land for a predetermined amount of time. Students can observe if one type of seaweed dries faster and if other factors are evident in the types of seaweed that affect their ability to survive longer than other types.
  
  

Fertilizer

• Organic fertilizers are used by many farmers to aid crop growth, and seaweed is considered one of those fertilizers. Students have the opportunity to test the positive reaction of seaweed as a natural organic fertilizer on plants that are commonly grown by local farmers. Information from the experiment could assist those involved in local agriculture. To accomplish this, students will need to research what crops are locally grown and then select some of the plant types that can be grown in pots in the classroom. Students should then select a type or types of seaweed to be cultivated into the soil that the plants are potted in and be prepared to record plant growth. A time limit should be set for the project and students should make a hypothesis about the results prior to starting to compare with the final results.