beach science

Usually we have the Bug of the Week series on Wednesdays, but since we are going with an ocean science theme this week, let's take a look at a group of marine invertebrates, the jellyfish, instead



Jellyfish live in oceans throughout the world. They can be a variety of shapes and colors.


In general, jellyfish have a bowl-shaped main body called the bell. They also have slender tentacles that usually contain the stinging cells or nematocysts. The jellyfish in the photograph above have long, slender strand-like tentacles, but some species have only a tiny fringe of tentacles along the edge of the bell, or even no tentacles at all. The frilly, lighter colored parts are the oral arms, which help capture and move prey.

Jellyfish range in size from those having a bell about 2 cm in diameter to some that are over 40 cm in diameter.

You can see some of the diversity of sizes and shapes in this video:

One concern that marine scientists have, which was mentioned at the end of the video, is that as the numbers of predators of jellyfish rapidly decline that jellyfish will become much more abundant and have more frequent blooms (see for example, this infographic).

Jellyfish Craft Activity

Learn about jellyfish anatomy by making a jellyfish model.




  • Coffee filters
  • Markers
  • Construction paper
  • Scissors
  • Yarn
  • Tape, glue and or stapler

Color the coffee filter with markers. It will represent the bell. If you have time, wetting the coffee filters will allow the marker inks to run and bleed together, making an interesting effect. If you wet them, allow the coffee filters to dry (on paper towels or wax paper to prevent the ink from staining other surfaces).

Fold the construction paper lengthwise. Have the children either cut strips to be the oral arms, or cut arm shapes as shown in the example, depending on their skill with scissors. Cut the yarn into 10 to 16 inch lengths, 6 or as many as desired.

Staple, glue or tape the oral arms into the center of the coffee filter "bell." Tape, staple or glue the yarn to the edge of the coffee filter to form the tentacles. You may want to attach another piece of string or yarn to the top and center of the coffee filter for hanging.

If your children are familiar with a particular type of jellyfish, modify the pattern accordingly.


Are you going to a beach sometime this year? Are you interested in learning more about jellyfish? If so, you might want to look into the citizen science opportunity known as JellyWatch.


This post is part of our ocean science series. Visit the landing page for links to all the related posts.


(Note: our usual Tuesday feature, Seed of the Week, will be back next week. Today we are going to visit the ocean. )

Algae and oceans go hand in hand, but what exactly are algae anyway? Are they plants? What are seaweeds and are they related to algae?

seaweed(Public domain photograph of seaweeds by Axel Kuhlmann)

Although algae may be large and appear plant-like, they are actually protists (belong to the Kingdom Protista). They have chlorophyll like plants so they can make their own food from the energy of sunlight, but they lack common plant structures like roots or leaves. Seaweeds, like that shown in the foreground of photograph above, are large forms of algae, also called "macroalgae." The small forms that float around in the water are often called "microalgae" or "phytoplankton."

You may be wondering why anyone would care about algae. Turns out, algae are important in a lot of ways. First of all, algae are the basis for aquatic food chains in both seawater and freshwater. They are also used for food, as fertilizer, and as a source of products such as agar and carrageenan. Algae are being studied as a potential source of biofuel. Let's not forget, they make a significant amount of oxygen. In fact, it is not too farfetched to think that algae might be the most important organisms on the planet!

Activities for kids:

1. Investigate seawater under a microscope

If you have access to a microscope, obtain a sample of seawater (or pondwater) and take a look at what is in it. Look for green, blue-green or even brown or red organisms that are algae. Examining samples under a microscope is fun because it often leads to surprises.

2. Make an algal collection

You can make a collection of pieces of algae or seaweed you find at the beach, similar to the way you make a plant collection. Some of them can have beautiful shapes and colors.

640px-Adolphe_Millot_algues(Illustration Adolphe Millot algues public domain from Wikimedia)

Gather pieces of algae on the beach and keep it moist in seawater. Once you are home, float the seaweed/algae onto a piece of heavy paper. Press the paper between layers of felt to remove the water and allow it to dry. The Hawaii Botany Department has step-by-step instructions on how to make an algal herbarium.


example-image(Figure 3 - Seaweeds are pressed on herbarium sheets for further study and repository in botanical Herbaria. The species that Dr. Suzanne Fredericq is pressing was found at about 66 m depth (200 ft) in the West Flower Garden Banks, and represents a new record for the Gulf of Mexico. -From NOAA)

If you don’t want to disturb nature, which is a good idea, you can take close up photographs of what you find instead. You can share what you discover via blogs, websites or photo streams.

Once you have a collection, visit some of these websites to help you identify what you have. Seaweeds are not too easy to identify, but you might at least figure out which group your sample belongs to.

Biomara has an extensive booklet of activities/lessons about algae to download (30.3 MB). The link for the "entire teaching resource" is right above the "Information for Teachers" bold header. It contains large color photographs of many common "macroalgae."

Who knows where studying algae might lead you. Perhaps you will be inspired to become a marine botanist, like Sylvia Earle (previous post).


This post is part of our ocean science series. Visit the landing page for links to all the related posts.



1 Comment

Oceans cover over 70% of our planet and have an incredible impact on our lives. This week we are going to delve into ocean science with some new books and hands-on activities for children.


This will be a landing page with links to all the related posts as they go up this week.

Expect to find:

Monday - Book review for a new children's nonfiction book, Sylvia Earle:  Ocean Explorer by Dennis Fertig.

Tuesday -  Incredible Algae!

Wednesday - Invertebrate of the Week:  Jellyfish, with information about the citizen science project called JellyWatch

Thursday - Gyotaku fish painting activity for kids

Friday -  Book Review of Searching for Great White Sharks by Mary Cerullo

Hope you enjoy having a little dip into ocean science.


The Monterey Bay Aquarium has ocean science curricula organized by grade level and by subject, as well as a 199 page Sea Searcher activity booklet available for download, and fun games and activities to do.

Do you have any ocean science books or activities to share? Let us know in the comments and we'll pin them to our Ocean Science Pinterest board.


We also have a growing list of ocean and beach science-themed children's books at our sister blog, Science Books for Kids.