A beach in Tunisia, in North Africa
Bibliography and further reading about seaweed, take a trip to the coast and go wading in the water. There is seaweed on pretty much any seashore, and you'll feel it winding around your feet as soon as you get in the water. There is also freshwater seaweed in lakes.
Try picking some of the seaweed and taking it out of the water. How is seaweed like other plants? How is it different? What happens to it when it dries out?
If you can't get to the coast, you can see seaweed wrapped around sushi in the store, and you can often buy sheets of seaweed in the Asian section of the store too. Try making and eating some sushi with your seaweed (also called "nori").