Movement in Earthworms Video Lecture | Science for Grade 6

[Intro]
You know, Squeaks and I spend a lot of time
underground.
And that means we’ve made a bunch of squirmy
little friends.
If you’ve spent any time digging in the
ground, you’ve certainly met them, too.
I’m talking about earthworms!
These animals are super cool, and super hardworking,
too!
Let’s see if we can get the dirt on these
wiggly worms.
First of all, even though you often find earthworms
outside, where you find insects like ants
and beetles, earthworms aren’t insects.
Can you spot the differences?
Remember what makes an insect: six legs, three
main body parts, and a hard exoskeleton.
Our earthworm doesn’t match that at all!
Earthworms have smooth skin and a body made
up of many small segments—it kind of looks
like they’re covered in a lot of little
rings.
And each segment has small hairs that are
almost too tiny to see.
And even though they’re long and skinny
like snakes, they’re not snakes!
Snakes have a skeleton, and earthworms don’t.
But they do have strong muscles.
In order to move, the earthworm squeezes its
muscles together, which makes its body thinner
and longer.
Then the earthworm uses those little hairs
on its body to hold on to the soil around
it, and pull itself forward.
Have you ever seen a bird trying to pull an
earthworm out of the ground?
The worm can make it hard for the bird, because
it can actually hang on to the dirt with those
tiny little hairs!
Now, just like most animals, earthworms have
a front end and a back end.
Up front, you’ll find their mouth and a
teeny tiny brain, about the size of a pinhead.
But that little brain gets the job done.
Earthworms are able to sense light and vibrations--so
they know when to wiggle away!
And when earthworms needs to wiggle away,
where do they go?
That’s right--underground.
Earthworms spend most of their time safe in
underground tunnels called burrows.
It not only keeps them hidden from predators,
but that nice, wet soil keeps their skin moist.
And that’s super important.
Because earthworms need to breathe just like
people do, but they don’t do it in the same
way.
They actually absorb oxygen through their
skin.
And in order to do that, they need to keep
wet.
That’s why you’re most likely to see earthworms
when you’re digging through damp soil or
mud!
But maybe you’ve seen earthworms even when
you haven’t been making mud pies.
Have you ever seen them hanging around on
the sidewalk after a rainstorm?
A rainy day for an earthworm is a perfect
moving day.
Sometimes one area becomes too crowded with
earthworms, so they need to find a new home.
But they need to keep their skin moist while
they’re out moving around.
So earthworms use those soggy days to come
out and look for a new place to live.
Then back into the ground they go!
But the dirt isn’t just a safe place for
worms to hide, it’s also their food.
As an earthworm moves through the soil, it’s
also is eating the dirt!
Earthworms get their nutrients from dead and
decaying parts of plants, like leaves and
roots, that are in the soil.
And earthworms are hungry.
They can eat half their bodyweight in just
one day!
But maybe the coolest thing about earthworms?
As they munch through the soil, they actually
make the soil better for the rest of us.
How do they do that?
Well, the tiny tunnels that earthworms make
as they wiggle through the dirt help bring
water and air deep into the ground.
And that makes it easier for other living
things -- like plants and fungus -- to live
in it.
Plus, as earthworms break down all of those
dead plant parts, they help spread around
all of the nutrients that are in them, to
make food for new things to grow.
Some people even keep earthworms in their
garden on purpose!
They feed the earthworms things like banana
peels and apple cores.
Then, the worms turn those scraps into compost
-- a rich, smelly, nutritious kind of plant
food made from … dead plants!
To you, it might just look like trash, but
to an earthworm?
It’s treasure!
Healthy earthworms means healthy soil!
And healthy soil means healthy people--because
we need it to grow plants for our own food!
So the next time you come across an earthworm--thank
them!
They’re hard at work helping flowers, trees,
grass, and plants grow.
And thanks to you for joining us here at SciShow
Kids!
If there’s anything that you’d like to
learn more about, ask your parents to help
you email us at kids@thescishow.com, and we'll
see you next time!