Oceanic Acidification & Seashells

Birds and their eggs aren't the only animals for whom an increasingly acidic environment would cause great harm.  This simple activity demonstrates the effect of acid on shellfish.

You'll need a couple of shells (large or small, any variety, but for the sake of comparison, it's good to have two of the same), two cups or beakers, vinegar and water.

Place each shell in a cup/beaker.

Cover one shell with water.  You might want to use salt water, as these organisms live in the ocean, but I didn't think of that as I was setting things up. You could also do three shells at a time - one in vinegar, one in water and one in salt water.

Cover the other shell with vinegar. 

You'll notice that the shell in the vinegar immediately begins to form bubbles and fizz.  The vinegar is breaking down the calcium carbonate that composes the shell. 

Within 24 hours, you'll notice the shell that was in vinegar has holes in it.  If there was still a creature living in the shell, this could obviously be detrimental.

Vinegar, while a weak acid, is quite a bit stronger than acidified ocean water.  The stronger acid speeds up the process, making it visible within a short period of time - perfect for students to grasp an understanding of the process.  Shells in an acid ocean environment would be subject to the same chemistry, it would just take place at a slower rate.  

You can learn more about the chemistry taking place, as well as ocean acidification here.  

You may wish to continue to leave the shell in the vinegar for an extended time to observe further.  If so, it may be necessary to replace or replenish the vinegar.  (I used a small enough amount of vinegar that the chemical reaction came to a halt within a day or so).

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Let Us Weigh Lettuce

An easy lesson in measuring mass, collecting data, graphing (if you wish), percentages and plants. And a great experiment to start at the beginning of the school year.

You'll need a leaf of lettuce and a balance.  The precision of an electronic balance is nice for this particular activity, if you have one available.

If you have a balance that can remain dedicated to this activity, you can place the lettuce leaf right on it.  Record the mass.  Each day when the students come to class, they should record the mass of the lettuce.  Continue recording the mass every day for a month.

[If you cannot dedicate a balance to the activity, you'll need to first find the mass of a weighing paper.  Record that, then place the lettuce on the weighing paper and record that mass.  Lift the paper with the lettuce on top and keep in a safe place while the balance is being used elsewhere.  Return the paper and lettuce to the balance each day to find the mass.  You'll have to subtract the mass of the weighing paper from each measurement to get the mass of the lettuce.]

Once you've collected all the data, you can graph it if you wish.  Is the water lost at the same rate throughout the month or does it change?

You can also determine how much of lettuce (by mass) is water.

Mass of lettuce at start - Mass of lettuce at end = Mass of water

(Mass of water / Mass of lettuce at start) * 100 = % of lettuce mass that was water

If you've caught your students' attention with this one, you can proceed to follow the same procedure to find the water content in other items.  Maybe your students will want to compare the water content in different types of lettuces or different types of leaves or different types of fruits or vegetables.  Lots of possibilities - you could have something going every month of the school year!

Body Systems: Nervous System: Brain Model

The human brain, at full-size,  is about the size of a full sheet of newspaper (or a pillow case), that's folded up to fit in your skull.

Keep your eyes open for a sheet of newspaper that has a full page ad that has some writing, but a large white space.  When you're born, your brain already has a lot of information stored in it, represented by the writing on the page.  But there's also a lot of room to learn more.  That's the white space on the paper - the brain space that's left to "write" on.
 
It's difficult to put numbers on how "full" one's brain is at birth and how much "room" there is for future learning, as the more you learn the more connections your brain makes.  It appears that there's always room for more learning to take place and that the brain is never "full" (to our current knowledge). 

Cells: The Importance of Cell Walls

 Cell walls prevent plant cells from bursting. 

Blow up a balloon until it pops.  An animal cell (or a plant cell that's missing a cell wall for some reason) is like this balloon.  Water can flow into the cell until the membranes bursts. 

Now place a balloon into a length of pantyhose and proceed to blow it up.  It will be harder and harder to blow up the balloon because the nylon restricts the balloon.  Virtually impossible to blow it up enough to pop it.  In the same way, the cell wall prevents the cell from reaching its bursting point. 

Sound: The Clanging Hanger

This is a simple demonstration that helps make the point that sound needs something to travel through and that air is not a very efficient material for that purpose.

You only need a wire coat hanger and a long length of string.

Tie the string onto the hanger, so that the hanger hangs from the middle of the string.

Swing the hanger from the string so that it bumps into something (a table, chair, wall, etc.) and take note of the sound it makes.  It's kind of a short, clang-y sound.  Nothing very dramatic or melodic about it.

Now, wrap one end of the string around one of your index fingers and the other end around the other index finger.

Place your fingers in your ears (gently, there's no need to jam them in).

Swing the hanger so that bumps into something once again and take note of the sound it makes.  Louder and more like a gong or large bell ringing.

In the first trial, the sound made when the hanger hit the object had to travel through the air to reach your ear drum.  A lot of the sound was lost on the way to your ear.  In the second trial, the sound vibrations travel from the hanger through the string and your fingers to your ear.  Much less sound energy is lost in route and it makes an audible difference. 

Dandelion Curls

It's spring in the northeast and that means (at least in my yard): Dandelions!

Did you know you can use dandelion stems to teach a simple (and pretty fun) lesson in osmosis as well as introducing the terms hydrophilic and hydrophobic?

Separate the stem from the flower and pull the stem into long strings.

Drop the strings into a tub of water and watch the stems curl up into all kinds of fun shapes! 

 If you drop the stem pieces one at a time, you can actually watch the curling process take place within just a minute or two.  Or you can dump a whole bunch in and have fun sorting through the results!

 What's happening?

The inside of the stem is hydrophilic, which is sometimes referred to as water-loving.  It's the part of the plant that absorbs the water.  And when it's placed into a tub of water, there's a whole lot of water to absorb!  The water moves into the cells through the process of osmosis. 

The outside of the stem is hydrophobic - it repels water.

The cells that make up the inside of the stem absorb so much water that they swell up.  The cells on the outside of the stem stay the same size.  The increasing size of the cells on the one side of the stem forces the stem into curls of various shapes.  

There's definitely something fun about sitting outside on a warm day and watching the curls form!  And if you can't be outside, grab some dandelions on your way to school and bring a bit of the outdoors in for your students.   

PS The idea of one side expanding more than the other side is similar to the way a bimetallic strip in a thermostat works.  The expansion is caused by temperature instead of water movement and it isn't as drastic as this, but it's conceptually similar. 

Body Systems: Nervous System: The Importance of Cerebrospinal Fluid

Cerebrospinal fluid (CSF) is the liquid that surrounds your brain and prevents your brain from smashing in to your skull. 

Here's a simple little demonstration that shows just how crucial that fluid is.

You'll need a small container (with a tight-fitting lid), 2 eggs and some water.

Throughout the demonstration, the egg yolk will represent your brain and the container will represent your skull.

Crack one egg into the container and put the lid on. 

Agitate the container - you can just shake it, or you can have a student run a few laps around the room with it for it.

Open the container and observe - scrambled brains!

Clean out the container and crack the second egg into the container. 

This time, before putting on the lid, fill the remaining space in the container with water. 

Agitate the container once again.

Open the container and observe - the egg yolk remains intact.  (The egg what froths up a little bit, making it difficult to see at first, but the whole yolk is there).

The water cushions the egg yolk, just as the CSF cushions your brain. 

Great visual explanation!

Coral Reefs: Build a Coral Reef

Most of the books featured in the Picture Book Science series have been works of fiction. Coral Reefs differs in that it's a non-fiction picture book.

It's a beautifully illustrated book, filled with easy-to-understand facts about the formation of coral reefs and the habitats they create. 

Have your students work together to create a coral reef in your classroom. 

Each student is given a balloon to cover in newspaper strips coated in paper mache.  You can use your favorite paper mache recipe, watered down white glue or liquid starch.

I skimped on the newspaper strips, but your students will cover their balloons more thoroughly.

While the balloons are still wet, stack them together.

When the paper mache has dried, pop the balloons. 

Remember, yours will look much better because the students will have been more thorough with the newspaper, and it will be a larger structure.

The balloons represent the living organisms and hardened newspaper represents that hardened shells of the organisms.  When the organisms die (i.e. the balloon is popped), the shells remain. 

This model is great at showing how fragile coral reefs are.  And it provides a neat prop for your further study of coral reefs and the animals that inhabit them.

The Empty Lot: What Can you Find in a Square Meter

The Empty Lot tells the story of man who thinks he's selling an empty lot, but he comes to learn that the lot is far from empty - instead it's home to a great many living things.

Have your students head outside on a nice day.  Mark off one-square-meter squares, using string or yarn.  These will be your students "lots".  The lots can be on a variety of terrain - grassy areas, parking lots, etc. 

Before students explore their lots, have them guess how many different living things they'll find evidence of in their lot. 

Have students carefully examine their lot to see how many different living things they can find (or evidence of living things).  They can carefully move leaves and grass aside, but shouldn't pull anything out of the ground.  And, they should try to replace anything they move to the best of their ability.  Students may also wish to use magnifying glasses to make closer observations. 

Student should keep a list of the things they find - naming the ones for which they know the names and providing careful illustrations for the ones in which they don't know names.  Upon returning to the classroom, students can use their observations and reference books to identify the unknown objects. 

Were your students surprised by the number of living things they found?  How did the different terrains vary in their living components?  What impact do human habitats have on other creatures' habitats?

By the way, The Empty Lot is illustrated by Jim Arnosky, who has written (and illustrated) a plethora of picture books about nature.  He's well worth checking out if you're looking for some books to accompany any studies of animals or plants. 

Wild About Books: Insect Haiku

If you aren't familiar with Wild About Books, you should be - it's a fun read and a favorite in our house.  But, beyond that, you can incorporate it into your study of insects.

After the animals have learned to love to read books, they begin to write their own.  And, the insects begin writing haikus (and the scorpion gives each a stinging review).  Four of these haikus are included in the story.  Share them with your students and then have them try writing their own haiku that includes some facts they've learned about insects.

Maybe they could even write their finished poem on a piece of paper cut into the shape of their chosen insect for a cute display.  

In case you've forgotten, a haiku has three non-rhyming lines.  The first contains 5 syllables, the second 7 syllables, and the third 5 syllables.

Diary of a...: Writing Prompt

Doreen Cronin's Diary of a Worm, Spider and Fly are silly tales about each of the respective animals. 

While the stories are far-fetched enough to garner lots of giggle, they are based on real attributes of each of the animals. 

If you're looking to have your students do something a bit more creative than the traditional report after researching an animal, consider having them follow Cronin's model and write a "Diary of a _____". 

Turtle, Turtle, Watch Out!: Turtle Hurdles

Turtle, Turtle, Watch Out! follows one sea turtle from egg to egg-laying mother, through challenge after challenge, some man-made, some the natural order of things. 

This story and activity could be used in any number of units: the ocean, animals, predator/prey relationships, human impact on nature, etc.

Begin the lesson by reading the story aloud to the students.  While they're listening, have them write down challenges the turtles face as well as the good things that happen that aid the turtle's survival.  Or maybe you'll want to read the story twice - the first time just for listening, the second time for taking notes.  As a class, you can brainstorm additional items to add to each list, if you desire.

Next, each student will make a cootie catcher.  If you or your students are familiar with making these, I've included directions at the bottom of the lesson.

Label the inside of your cootie catcher as shown:

Now, pick 8 items from your lists - 4 from the list of challenges, 4 from the list of "good things". 

Open the flaps of your cootie catcher and write one item under each letter.  The order in which you write them can be completely random.

You'll also need to make a simple mat (one for the class) - use the following picture as a guide - and get a die.

Now you're ready to play. 

To being with, everyone needs to stand up - everyone is a thriving baby turtle.

The teacher, or other designated party, rolls the die onto the mat.  Each student manipulates his/her cootie catcher the number of times indicated by the die.  Then the students read the message under the letter that corresponds to the letter the die landed on.

Students whose message is a challenge or threat to the turtle sit down - they haven't survived.  Students who receive a message of a "good thing" remain standing.

The students who remain standing play another round in the same manner.  Try to play 5 rounds, or see how many rounds it takes for all students to be sitting.

Baby sea turtles face a lot of challenges in making it to adulthood, as do many other animals.  Hopefully this fun game helps your students understand just how few babies survive to adulthood and encourages them to think about the impact of their actions on other species. 

To Make a Cootie Catcher

Begin with a square piece of paper. (I cut 8.5x11" paper into a square).

Fold the square in half along the diagonal.

Unfold.  Fold in half along the other diagonal.

Unfold.  You'll have a square piece of paper, with the fold lines making an X across it.

Pick one corner of the square, and fold it, so the point is at the center of the X.

Fold in each of the additional corners of the square.

Turn your newly formed square over.

Repeat the previous step, folding each point into the center of the square

Label the sections, as directed above.

Fold the cootie catcher in half, to make a rectangle. 

Place both your thumbs and index fingers under each flap to work the cootie catcher.

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This activity is adapted from "Turtle Hurdles," published in Picture-Perfect Science Lessons by the National Science Teachers Association.