Planning a day trip to the ocean or studying marine ecosystems with your kids? Whether you are looking for ways to integrate Science into your home school curriculum or just looking for an easy way to integrate Science into your child’s daily life. This seaweed activity is sure to be a hit with your kids.
This science activity was inspired by a recent trip to the coast. I love integrating science into every day experiences. There is so much to be learned by using what you already have available to you.
Turn this activity into a formal science lesson to go with a larger unit. Or use it as a discussion starter while exploring the coast together.
In this post I’m going to explain how to compare and contrast two samples of seaweed. This post is geared towards elementary and middle school aged students.
Make sure to check out the end of the article where I give specific lesson ideas for how to extend this activity. Along with resources to help your kids learn about seaweed.
Collecting Seaweed Samples
Even on a cold dreary day I was able to collect samples of dried up seaweed. For ease of transport I collected dried verses living seaweed. I wasn’t prepared to bring home soaking wet seaweed in 45 degree F (7 degree C) weather!
Washed up seaweed on the shoreline makes for a perfect observation based science lesson. You can find dried seaweed for free at the coast almost any time of year. Only two small samples are needed.
If you prefer to use live seaweed you can wait until the weather warms up. Or head to the beach at low tide, live seaweeds are accessible when the tide leaves rocks and seaweed exposed even in the winter.
Fun fact, seaweed is not a plant. It is actually a type of marine algae. Scientists classify seaweed as part of the Protista kingdom. Seaweeds are a valuable part of marine ecosystems.
Science Skills vs Science Content
But wait, what if I know nothing about seaweed?! That is okay, you do not need to have any prior knowledge to practice making observations. In my example I’ll show you how you can do this even without incorporating content specific vocabulary.
When teaching Science, it is important to focus on strengthening skills, not just studying content. Skills include: making observations, comparing, analyzing, trying to solve a problem, etc.
Noticing the color variations and texture of an object are scientific skills. Science content includes topic specific vocabulary and concepts. Marine ecosystems and the different types of seaweeds are all science concepts.
It’s Okay to Not Know the Content Yourself
Don’t let not knowing all of the answers stop you from practicing science with your kids. For this lesson, you can focus on both skills and concepts.
I’ll explain ideas for how you can integrate both. However, you can use this activity as a way to simply practice scientific skills if that is your goal.
I’ll warn you, often times, kids will naturally get interested in science concepts once they make observations and make comparisons. Observations can lead them to ask content specific questions. Which is awesome! Again, resources will be listed at the bottom of the post.
Seaweed Observation Learning Goals
For this lesson, kids will be using observations to compare and contrast two samples (varieties) of seaweed.
You only need to use your eyes to make observations. If you are looking for ways to make more detailed observations you can use a magnifying glass. Older children can also use a ruler to take measurements.
To do this lesson you will need two different samples of seaweed along with pencils, paper, and a ruler. If you are going to informally discuss the similarities and differences, then you only need the seaweed samples.
- Find and collect at least two different varieties of seaweed.
- Check to make sure they actually are different before you stop your search.
- Decide which seaweed sample will be #1 and which is #2
- Find a place to sit and write or bring the seaweed samples home.
- You will need a ruler, plain paper, and a pencil (or one of the free printables below)
- Fold your paper into three columns or use the ruler to draw three columns
- Practicing using a ruler to properly set up a data table is an important science skill
- I encourage you to let you children create their templates themselves
- If recording on paper, label the columns Seaweed #1 / Both / Seaweed #2
When doing an informal discussion, you can skip the steps involving paper and pencil. Simply take a break from exploring and sit in the sand or on some rocks and talk about the seaweed samples.
For the rest of the directions, I am going to explain how to do this formally as a written assignment. Follow the same ideas if doing a discussion, but have kids verbally describe their observations.
Don’t stress, the goal here is to have fun and make new discoveries together!
Starting the Lesson
- Provide some type of opening or explanation where you tell your kids what they will be doing.
- Encourage them to use their eyes along with sense of smell and touch to observe the seaweeds.
- Give them time to look at each sample before writing anything down.
- Children need time to process and make detailed observations. Provide encouragement without giving them the “answer.”
I encourage children to think of themselves as nature detectives. Even small details can provide clues about the differences between the two types of seaweed.
Elementary Aged Learners
Younger children may need more prompting and assistance to get started. Ideas for prompts:
- point out one difference in texture
- ask them to identify the color(s)
- have them point out different shapes
- encourage them to hold the sample
- bring along a magnifying lenses to help them feel official
Middle School Aged Kids
Older children will jump right in and notice easy to spot differences and similarities. They might state the colors of the samples. Seaweeds tend to have bubbles or pockets of air which they will probably pick up on.
Provide prompting to encourage older children to look more closely. Often times seaweeds will share a common characteristic such as having long strands. However, when you look closer, subtle differences between the long strands can be found.
Using a Venn Diagram to Organize Observations
In fancy terms, Venn diagrams are an organization tool used to group observations into similar characteristics (one column) or different characteristics (two separate columns). Think of two overlapping circles. The space where they overlap represents the shared traits.
You can have you kids use a circle Venn diagram, free printable below. However, I prefer to use the thee column method because there is more space to write. You can find that free printable below as well.
Elementary aged kids might benefit from the circular version because it visually shows with the overlap that there are similarities. Use what works for you and your kids, there is no wrong way to do this.
After kids have had time to look at the two samples, let them start writing down observations. Divide them by similarities and differences. It can help to look at one trait, say color, for both samples and write down the observations.
Remember, similarities go in the middle column or overlap. No need to write in complete sentences, use shortened points.
If your child is not thrilled about writing everything down, encourage them to make a sketch and visually show the traits.
Challenge them to see how many they can find or encourage them to identify a specific number of differences. The number will vary per child depending on their age and or skill level. This activity is really easy to modify depending on the needs of your kids.
Optional Additional Lessons and Activities
- Have children share their observations
- Make a formal drawing with labels and measurements (labels can include simple observations such as air bubble or hole)
- Use water color paints and water color paper to create a painting
- Turn the Venn diagram into a formal compare and contrast writing piece (1 or 3 paragraphs)
- Use a camera to take pictures of different varieties of seaweed (alive and dead)
- Find a recipe, gather supplies, and make a seaweed snack
- Write a creative writing piece about the day in the life of your seaweed samples
- Make Pressed Seaweed Art (Activity Guide)
- Read a few books about seaweed
- Conduct research online to learn more about seaweed
- Create their own field guide using the photos they took and their research
- Addition Seaweed Lesson Plans from the University of Maine
Extend the Lesson with Books
Books are a wonderful resource for parents who are educating their children. A great deal of content can be learned through informational texts. See the list below for seaweed resources in book form:
East Coast of United States
- Seaweed: Marine Algae from the Northeast Coast by J. Roach-Evans
- Life on Intertidal Rocks: A Guide to the Marine Life of the Rocky North Atlantic Coast (Nature Study Guides) by C. H. Day
- Seaweeds: A Color-Coded, Illustrated Guide to Common Marine Plants of the East Coast of the United States (Keystone Books) by C. J. Hillson
West Coast of United States
- Pacific Intertidal Life: A Guide to Organisms of Rocky Reefs and Tide Pools of the Pacific Coast (Nature Study Guides) by R. Russo and P. Olhausen
- A Field Guide to Seaweeds of the Pacific Northwest (Pamphlet) by B. Clarkston
- Pacific Seaweeds: Updated and Expanded Edition by B. Clarkston
- *Seaweeds of the Pacific Coast: Common Marine Algae from Alaska to Baja California (illustrated edition) by J. Mondragon and J. Mondragon
- *Seaweed Chronicles: A World at the Water’s Edge (Audible Audiobook) by S. Hand Shetterly
*Since a few of the books are reference books, they are not written for kids. The small nature guides and pamphlets may meet your needs better than the books written for adults. I wanted to include them as a resource in case you want to learn more about seaweed alongside your kids.
If you find additional books about seaweed that are written specifically for kids, please let us know in the comments below!
Online Resources for Kids
- Kids Britannica seaweed page
- Sciencing.com Seaweed Facts for Kids article
- New World Encyclopedia article