Tide Pools Lesson for Grades PreK-2
You can introduce your young children to the many
incredible creatures that dwell in the oceans of the world, whether you live
near one or not. This Teaching Tip focuses on shoreline tide pools and can be
used as a basic framework for teaching kids about the plant and animal life most
commonly found in them. Be sure to ask a lot of questions to get kids thinking
and provide them with opportunities to ask their own questions as well.
Depending on what your children already know about oceans, you might need to
give them a quick overview before you begin talking about tide pools. Help them
locate the oceans of the world on a globe or a map in comparison with where you
live. If your family has been to the beach, ask your kids what they remember
about the ocean.
Tides
Explain that the water in the ocean is constantly moving.
Although it may be difficult for kids to grasp, you can explain how tides are
caused by the force of gravity from the moon and the sun pulling on the ocean
waters of the earth. When water moves up onto the beach we call it high tide
and when it goes back down, we call it low tide. There are usually two
high and two low tides each day.
What's a Tide Pool?
When the high tide comes it brings water, plants, and
animals with it. When the tide takes the water back out to the ocean (at low
tide), some water gets trapped in low spots in rocks or sand on the beach. The
trapped water forms a little pool called a tide pool that becomes a home
for many ocean creatures and plants. Shores that have large rocks have the most
tide pools, but sandy beaches sometimes have them too. You can watch a video of
a tide pool at the Monterey Bay
Aquarium. Some animals that live in tide pools
are crabs, clams, mussels, barnacles, snails, urchins, anemones (say: uh-NEM-uh-neez),
nudibranchs (say: NEW-dih-bronks), starfish (or seastars), and sea cucumbers.
Occasionally, small fish or an octopus might find their way to a tide pool and
plants such as algae, seaweed, and kelp also grow there. Show a picture or model
of each animal as you talk about it. This
tide pool animals site
has information about common tide pool dwellers.
Surviving in a Tide Pool
A tide pool can be a very dangerous place to live. At high
tide, waves come crashing onto the shore with very powerful force. The waves
cover the pool with water and bring fresh seawater and more plants and animals
for food, but then the tide goes out again (at low tide) and most of the water
in the pool goes out with it. Then the sun beats down on the pool and starts to
heat things up. Also, shore birds, like seagulls, like to eat many of the animals that
live in tide pools. Introduce the terms prey and predator to your kids. The tide
pool animals are prey to birds and the birds are predators of the
smaller animals. There are also prey and predators within the tide pool.
So how do all of those creatures survive the many dangers
of the tide pools they live in? Most animals have a way to defend themselves
built into their bodies. Below are some examples; see if you and your kids can
think of others.
Hide-n-Seek
One way to stay alive in a tide pool is to keep from being
seen! Some animals, like an octopus, can change the color of their skin to blend
in with their surroundings. This is called camouflage. A funny looking type of
crab, called the decorator crab,
attaches anemones, corals, and other things to its shell to disguise itself!
(These crabs usually live in coral reefs, but can also be found in tide pools.) Other
animals hide by burying themselves in the sand. Crabs often bury themselves so
that only their eyes stick up - that way they can see their predators, but their
predators can't see them!
Hard As a Rock
Animals that live high on rocks, like barnacles and
limpets, have very hard outer shells (called exoskeletons) that protect them
from becoming dinner for hungry seagulls! They also store water and food inside
their shells so they can stay alive even when they are not covered by water.
Crabs also have exoskeletons that act like armor to protect their soft bodies.
Snails and hermit crabs carry their protection on their backs, just like
turtles. When things start looking dangerous, they can just pull into their
shells for safety.
Hang On
What happens when the harsh waves from the incoming tide beat down
on the animals? Don't they get washed away? Barnacles, anemones, and starfish
all have special sticky suction cup-type feet that they use to attach themselves
to solid rocks so they won't be washed away. In fact, once they stick to
something, it is almost impossible to move them until they release themselves!
Fabulous Fact
 Anemones are covered with sticky
tentacles that they use to catch their food. Each tentacle can sting any animal
it touches. The sting paralyzes the animal so it can't move or defend itself and
the anemone can eat it. Sometimes anemones are called flowers of the sea because
they are so colorful. Even though they look like plants, they are actually
animals. They have a stomach and a mouth, but no eyes or even a head. Some
anemones can grow up to two feet across and live for up to 80 years!
Activity: Underwater Viewer
If you are planning a trip to the beach, have your kids
make a viewer they can take with them and use to watch things living in the
water. (You can also use this in a nearby pond.)
You will need:
- 1 clean empty tin can (a small coffee can will work well)
- 1 gallon size plastic zip-lock bag
- 1 or 2 thick rubber bands that will fit tightly over the can
- Black paint (optional)
- Plastic waterproof tape (optional)
To make the viewer, use a can-opener to remove both ends of the can. Painting
the inside of the can black will make it easier to see animals underwater. Cut
off the zipper and the three sealed sides of the plastic bag to make two sheets
of plastic. Place one piece of plastic over an end of the can and secure it with
the rubber bands (throw the other piece away). Make sure to pull the plastic
tightly over the rim of the can to make a smooth viewing surface. Sealing the
edges of the plastic above the rubber bands with waterproof tape will help keep
water out of the viewer. To use the viewer, stick the plastic-covered end into
the water and look through the open end.
If you won't be near a beach anytime soon, your kids might
enjoy making their own tide pool. Fill a large container with water, add some
large rocks, and then let your kids make models of tide pool creatures and
plants out of waterproof clay to put in the pool.
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