Category: science projects

Pumpkins

By , November 11, 2011 6:07 pm

It’s fall and a perfect time to study pumpkins!

First I read the class Pumpkin Circle: The Story of a Garden by George Levenson and Shmuel Thaler, a lovely book about the life-cycle of a pumpkin.  The photos in this book are gorgeous.  We talked about the circularity of life.

Next I cut open a pumpkin at school and had the children identify the rind, the pulp, the stem, and the seeds.  We then made little Montessori “Parts of the Pumpkin” books.

I explained to the children that we would not waste our pumpkin and we would be eating the pulp and the seeds.  Several of them seemed somewhat aghast at the prospect.

I roasted the seeds in the oven at school so the children could enjoy the lovely smell and hopefully be more encouraged to try them!  Only one child out of a class of twenty-five did not wish to try one, and of all those who tried, only two did not clamor for seconds and thirds.  This was a huge hit!

I took the rest of the pumpkin home and made pumpkin bread with the pulp.  That will be going to school tomorrow and I think all will enjoy it.

In the interest of scientific research we put some of the pulp and a few seeds in a tightly sealed jar.  I labeled it with the date and placed it on the science shelf.  I asked the children to predict what, if anything, would happen to it.  A few predict it will stay exactly the same forever.  A few said it would grow mold.  I told them to inspect it every day to see for themselves.

(Next year we might try this clever version of the decaying pumpkin experiment!)

We also cut the top of a second pumpkin and filled it with dirt.  We watered it and set it in a sunny window to see if the seeds would grow.  I’ll report back on the results.

NOTE (added March 4, 2012):  This turned out wonderfully!  Please see the next post, What We’ve Been Up To for details and a photo of it now!

I dyed some pumpkin seeds red, orange, yellow, and green and set them out in bowls on a tray with some black construction paper.  They have been making pictures and designs with them.

Finally, I put this simple pumpkin color-by-number on the shelf along with a laminated completed one to use as a guide.   It has been popular.

(Oh, and we also painted pumpkins at our school’s annual Fall Festival!!)

 

Sources

Growing in Pre K – Post: Pumpkins

 

Recipes

ROASTED PUMPKIN SEEDS -

Rinse the seeds thoroughly and remove all pulp and strings.  Spread them out and let them dry on paper towels.  Put in the seeds in a bowl and add just a TEENY TINY bit of olive oil to make the seasonings stick (not too much, or they will be greasy).  Toss to coat them in oil, then add seasonings and toss again.  I use Jim Baldridge’s Secret Seasoning (yum!) but you can use anything you like, even just salt.  Some people do cinnamon and sugar, however I like mine savory and have never tried this.  Spread them on a cookie sheet lined with parchment paper. Try to spread evenly so very few overlap.  Bake in a 250 degree (Farenheit) oven (this is fairly low heat for those who do not use Farenheit).  Check them after 45 minutes, but they might take an hour to an hour and a half at this temperature to be done.  They are done when crispy seeming and crunch loudly when bitten.  NOTE: They might not brown much, but as long as they crunch, that is OK!

PUMPKIN BREAD -

Ingredients :

  • 1 and 2/3 cups all-purpose flour
  • 1 teaspoon baking soda
  • 3/4 teaspoon ground cinnamon
  • 1/4 teaspoon ground ginger
  • 1/4 teaspoon ground cloves
  • 1/4 plus 1/8 teaspoon kosher (ie. course) salt
  • 1 and 1/3 cups sugar
  • 1/3 cup canola oil
  • 1 cup plus 1 and 1/2  tablespoons canned, unsweetened pumpkin (or fresh pumpkin pulp that has been boiled, or roasted in water and removed from the skin)
  • 1 large egg

Preheat oven to 350 degrees (Farenheit, a medium setting for those who do not use Farenheit).  Grease and flour an 8.5 x 4.5 inch loaf pan.  Sift together first 5 ingredients then stir in kosher salt.  Combine sugar, oil, and pumpkin in a large bowl.  Beat at medium speed with an electric mixer until smooth.  Add egg, beating until well-blended.  Gradually add dry ingredients, beating at low speed until blended.  Pour batter into pan.  Bake for about 1 hour and 5 minutes or until loaf is golden and a wooden pick inserted in the center comes out clean.  (NOTE – I start checking on it early.  It will be dry if you over-bake.)  Let cool in pan on wire rack for 15 minutes, then remove from pan.  Serve warm or at room temperature.

Fireworks in a Dish

By , March 6, 2011 4:35 pm

If you have milk, food coloring and dish washing soap on hand…

you can have impressive rainy-day science fun!

Pour some milk into a plate:

Wait a minute for any motion in the milk to settle down, then add four drops of different colors of food coloring.  Place the drops next to each other near the center of the plate.

 

Wait a minute or so until the colors get a bit blotchy-looking:

 

Take a clean cotton swab and gently place it on the colors.  What do you think will happen?

(SPOILER ALERT:  Absolutely nothing.)

Now put a drop of dish soap onto the other, clean and dry end of your swab.

What will happen when you put the soapy swab gently onto the colors?  Look!

It even continues impressively swirling and churning after you have lifted the swab out of the milk!

Try putting your swab in different areas of the plate to see what new patterns form.

NOTE:  It is very important not to stir, just hold your swab still in the milk.

Make sure you have plenty of milk and food coloring on hand for this because your kids won’t want to do it just one time.  This kept my 5 year-old entertained for at least an hour!

Many thanks to Steve Spangler’s Science Experiments for this really fun idea! Steve Spangler has a good explanation of the science behind this colorful display. You can read it here.

___________________________________________________

This is my contribution to this month’s Unplugged Project theme of soap.  Can you come up with a soap-themed project?  If so, please join in and add a link or comment to the original project post.  You can read more about the Unplugged Project here!

Magic Expanding Hand!

By , February 26, 2011 7:50 pm

Here is a fun science experiment that will totally entertain your kids AND teach them a bit of chemistry. Great rainy day educational fun!

  • INGREDIENTS:  All you need is vinegar, baking soda, and a latex glove. (Baking soda and vinegar happen to be my very favorite toys!

    You probably have the baking soda and vinegar in your pantry already, all you need to find is the glove (think hospital, doctor, dentist, lab…). We had a cool purple one. If you can’t find a glove, how about a balloon Magic Expanding Head?  This would be even more funny if you drew a face on the balloon first.

  • HOW:  Pour some baking soda into the glove,then carefully pour in some vinegar.

    You can be scientific and test which proportions work best, or just “wing it” like we did (about 1/3 cup baking soda, and 1/3 cup vinegar) . Squeeze the glove tightly closed with your fist, or if you work fast you might be able to tie the wrist up like a balloon. The glove will rapidly “grow” into a giant-sized hand (shake if necessary).

  • TIP:  Pouring in the vinegar is the tricky part since you might have to work fast to close off the opening of the glove before a geyser occurs in your kitchen. Although I know from experience that children are extremely impressed by the geyser-effect, you will be less so. Unless you are a Way-Cooler-Mom than I am, I recommend working quickly and conducting this experiment over a sink, or better yet … outside!
  • LESSON:  The quick answer is that the baking soda and the vinegar, when mixed, recombine to form Carbon Dioxide gas (CO2) and water (H2O).  It is the gas that fizzes, bubbles and expands the glove.  (A more complete explanation can be found here.  And an even more thorough and lengthy one here.)

You can also perform a version of this using a balloon stretched over a bottle or a jar.

Invisible Ink Messages (“Messages” Unplugged Project)

By , January 23, 2011 4:00 pm

All spies love invisible ink.  In honor of this month’s Unplugged Project theme of messages here are two simple methods for making secret, invisible ink messages out of ordinary ingredients.

++++++++++

LEMON JUICE:

Either squeeze a lemon or be lazy like me and use that store bought lemon juice that comes in the little plastic lemon!  Put the juice in a small dish and use a cotton swab to write your secret message.

++++++++++

BAKING SODA & WATER:

Mix together equal parts baking soda and water in a small bowl.  Again, use a cotton swab to create your message.

++++++++++

Once the messages are completely dry and can no longer be seen on the paper, hold the paper over a heat source and the message will magically be revealed to guaranteed “oohs and aahs!”  (Obviously an adult should complete this step, especially with young children, so as to avoid burns and flaming paper.)

By the way, we found that the baking soda produced a slightly darker result than the lemon juice.

NOTE:

For those whose children channel James Bond rather than Martha Stewart, a high-tech invisible ink spy pen complete with built-in ultraviolet decoding light might be just the ticket. My son found this one in his Christmas stocking:

LINKS – More about invisible ink:
The Naked Scientist – Secret Messages-What Makes an Invisible Ink?
Kidzworld-How Invisible Ink Works
Science Project Ideas – Invisible Ink (this site has some other interesting methods too)

Secret Codes: The Cardan Grille (“Messages” Unplugged Project)

By , January 10, 2011 2:39 pm


My two oldest children are really into secret codes at the moment and when I asked them for suggestions for this month’s Unplugged Project theme, my 8 year-old son immediately said “Messages! We could make codes!”

So here is our first code, a version of the famous code known as the Cardan Grille.  For this code, a special template is used to encode and decode a message. Here’s how we made ours:

You’ll need paper (graph paper makes it much easier), a sharp pencil, scissors, a ruler, and a box cutter or razor blade.

First mark out evenly spaced boxes on your graph paper.  You will be cutting some of these into square openings, so you’ll have to leave some blank space around each box.  (Our boxes were two graph squares wide and two squares tall with one blank square between rows.)

First we marked off rows of squares then we drew the grid using the ruler.

Next we laminated our paper.  If you don’t have a laminator, you might want to paste it to some stiff cardboard or posterboard just to make it tougher.  If the grid gets lost or destroyed, no one can crack the code and you will be fired as a secret agent!

I used a box cutter to cut random squares out of the grid.  I put an old wooden clipboard underneath in order to avoid damaging the desk.  You could use pointy scissors for this step, but a razor-type blade makes the job much easier. (Obviously, an adult should do this step.)

The finished template (with my “helpers” in the background):

Now you are ready to encode.  Place the template over a fresh sheet of paper.  Mark around the corners with a pen to make it easier for the decoding person to line it up.  Write your message (one letter goes in each square).

Remove the template and fill in all the open squares with random letters.  Can you figure out what this says?

Here is the solution:

(“The girls are hiding the treehouse.” – OK, so it was supposed to say “The girls are hiding in the treehouse but we forgot the “in.” But coded messages are supposed to be brief, right?)

NOTES:

  • You can make your template as big or as small as you like.
  • For ease of communication between spies, you really ought to make a duplicate template so both sender and recipient have their own.  Just place the first template over a new piece of paper, trace the locations of the squares, laminate, and cut out.
  • I numbered the corners of the template 1 – 8 because you could use both sides and all four orientations to create different messages, or even one long one.
  • Traditionally, the template was placed over an ordinary letter (see the example here) but it can be very challenging to come up with a natural sounding message built around the coded text.  I gave it a try though and it was a fun mental exercise:

(“Arrival at six PM.”)

Blog Widget by LinkWithin

Panorama Theme by Themocracy