Posts tagged: science toys

Make a Salad Spinner Zoetrope

By , October 16, 2009 5:03 pm


The theme for this week’s Unplugged Project was wheel.  I searched around for ideas and came up with this one which sounded really interesting:  a zoetrope!

What is a zoetrope you ask?  (I didn’t know what it was either.)  A zoetrope works on the same principle as a flipbook, one of those little books where you flip the pages and it looks like an image is moving, but it uses a rotating cylinder to produce the illusion of movement.

I like this definition from Wikipedia:  “A zoetrope is a device that produces an illusion of action from a rapid succession of static pictures.”  The word zoetrope comes from the Greek zoe (life) and trope (turn), so it is really a “wheel of life,” perfect for our theme!

I found instructions for making a zoetrope many different ways:  using a round camembert cheese box, a PVC pipe, a straw and a printout, a paper plate, and ice cream containers.  We originally made up our own version out of black poster board, an old CD, a small lazy susan, and lots of tape.  It was OK, but a bit wobbly.

Then I found a totally ingenious person who made one out of a salad spinner!  Why didn’t I think of that?  We absolutely had to try it and the result was AWESOME!  It is an easy project that produces a maximum “wow factor.”  Try it, here’s how:

Use electrical tape to tape off the slits on the salad spinner basket leaving every third slit open. We used 3/4″ electrical tape and that just happened to be exactly the right size for the job.

For images, the salad spinner genius used cutouts of the phases of the moon from a calendar.  Very clever but I decided to draw my own pictures.

On a piece of white paper I marked off a series of 3/4″ x 3/4″ squares.

Then, using a black Sharpie, I drew a face with a changing mouth and waving hair, making each image slightly different than the previous one.

The tedious part was cutting out all 26 images and taping them in sequence to the blocked off areas of the inside of the salad spinner.

Finally, using a clump of rolled up tape, stick your zoetrope onto the overturned lid of the salad spinner, centering it as best you can. The zoetrope will be sitting on the rotating disk, and the salad spinner handle will be underneath.

Now for the fun: spin and look through the slots to see the “movie!” The view is best if you shine a bright light into the bowl of the zoetrope.

Hopefully you’ll see from this little 10 second video that we made, how cool this project really was!

Let’s not forget THE SCIENCE:

So how do flipbooks, zoetropes, thaumatropes (a rotating card with a different picture on each side, the pictures appear to combine when card is spun), cartoons, and old time film movies actually work?  Many people still believe in the “persistence of vision” theory, in which it is thought that an image remains in the eye for a certain time after the image source is actually gone (ie. the optic nerve is the cause).  Apparently that theory is no longer in favor these days.  A more popular theory at the moment involves something called Beta movement where the brain itself apparently combines rapidly flashing images thus forming a perception of movement (ie. the brain is the cause).  It seems that no one really understands any of this completely.


You can visit a real zoetrope at the following museums:

V&A Museum of Childhood, London, UK

The Ghibli Museum, Tokyo, Japan

Great Lakes Science Center, Cleveland, Ohio, USA

Headwaters Science Center, Bemidji, MN, USA

Have fun!

(Be sure to visit the links to other people’s wheel Unplugged Projects on last Monday’s Weekly Unplugged Project post.)

Fast – Rubber Band Car (Weekly Unplugged Project)

By , July 12, 2009 9:29 pm

The theme for this week’s Unplugged Project was fast.  This is a fast post because the week went really fast, and we will soon be flying in a fast airplane to France.

We did experiment with some rubber band powered cars, and finally succeeded in making an original prototype from a Knex Set that went very fast…for about 6 inches.  I think the axle needs work, as does the length of the rubber band.  It was fun, even though our model obviously needs improvements.

If you have budding engineers at your house, try this project and see what you can come up with!

Here are a few links to get you started:

PBS Kids – Rubber Band Car

Easy Propeller-Driven Rubber Band Car

LEGO Rubber Band Car


If you did a fast-themed Unplugged Project this week then please link to your post below (not just your blog, we always want to be able to find your fast post).  If you didn’t do a fast project, then don’t link, but please read more about how to join in the Unplugged Project here.  We’d love to have you!


Since I will be away until August 6th, the Unplugged Project will be on vacation also (although, if anyone is interested,  I hope to post a few virtual postcards from France, perhaps even one a day if I can!).

The next Unplugged Project will be Monday August 10th and the theme will be:


I bet we’ll have a lot of photos by the time we get home, and you’ll have a lot of time to think about what you will do with your photos!

Enjoy and have fun!


Powder – Baking Soda Boats (Weekly Unplugged Project)

By , May 3, 2009 7:22 pm

The theme for this week’s Unplugged Project was powder. I’ll admit that this particular choice was somewhat premeditated since I thought a baking soda project would be fun.  Baking soda is a powder, right?

Fondly remembering a baking soda boat that came in a cereal box once when I was a child, I suggested we try and make one. My children were enthusiastic but leery, remembering a particularly violent baking soda volcano we made one time!

I am sure they were rolling their eyes and thinking:

“Oh no, here goes Mom with the baking soda again.”

Is that what they’ll remember about me as adults?

“I don’t remember much about Mom, but she did like playing with baking soda and vinegar.”

I found instructions here on the PBS Zoom website for a boat made out of a plastic bottle.  Never being able to simply do what instructions say, I had to experiment, so we tried a sippy cup boat too!

We needed baking soda, vinegar, and our bottle and cup.

Using a hammer and nail, we made a hole in the cap of the bottle.  The hole is the exhaust pipe through which the carbon dioxide gas escapes propelling the “boat” through the water.

The sippy cup already had holes of course, but I covered up the vent hole with some masking tape so the only vents would be in the spout.

Supplies in hand, we eagerly headed off to the bathroom and put some water in the bathtub.

The Zoom website suggested wrapping the baking soda in toilet paper to slow the reaction.  Remembering my volcano, I thought this might be wise advice.

We poured baking soda onto a strip of toilet paper:

And rolled it up:

We tried the sippy cup first and poured in some vinegar.

Next we put in a few marbles to weigh down the spout (where the “exhaust holes” are), so it would be underwater.  Coins work too.  It is important that the exhaust holes be under the water line so there will be more resistance (of the water) to propel the boat.

The kids cringed when I dropped in the toilet paper package containing the baking soda.

I quickly put the cap on and placed the cup in the tub. The cup whizzed around the tub accompanied by many oohs and aahs.

The toilet paper worked nicely to delay the reaction giving me time to put the top on, but on the second attempt the toilet paper clogged the exhaust hole stopping the “boat.”

We tried the bottle too.  Same procedure:  vinegar, toilet paper/baking soda and marbles.  The bottle sailed around the tub.

Since we were having clogging problems with the toilet paper, we also got brave and dumped the baking soda in, poured in some vinegar and tried to get the top on quickly.   Unfortunately we were never able to be quick enough, and those boats didn’t work as well since, as you can see here,  a large part of the chemical reaction occurred before the top was on.

In light of my baking soda and vinegar obsession, this could become quite a project:  how to control the reaction without clogging, what sized hole produces the best results, what proportions of baking soda and vinegar generate the most power.  Nerd heaven!  Look out for a blog post one day with my perfected version of this project.

My kids went on to create their own experiment with baking soda and vinegar in a plastic wipe box:

Fortunately we ran out of baking soda before they were able to blow the box open!



Chemistry and ideas:  Baking Soda and Vinegar Science

Real Science:  Ask a Scientist-Vinegar and Baking Soda


Did you join us this week for a powder Unplugged Project?  If so, please link to your powder project post (not your blog) below.  If you didn’t join in, then please don’t link but read more about how it all works here.  We’d love to have you!


The theme for next week’s Unplugged Project will be:


Have fun!


Balance – Flying / Balancing Birds (Weekly Unplugged Project)

By , January 18, 2009 11:00 pm


Thanks to a suggestion from Meg at Bare Baby Feet, this week’s Unplugged Project theme is balance. We felt “sciency” this week, so my oldest daughter and I scoured our favorite science book but found nothing that sounded fun to her.

I did a few Google searches and happened across this amazing-seeming experiment.  I tried it and then showed it to my children who were very impressed.  As you will see, I tried to make it even more fun for kids by modifying it to make a balance toy:  a flying bird.  Read on for more!


This experiment (which I understand is often shown as a magic trick), involves two identical sharp forks, a real cork (a real one is a bit softer and easier to use than a plastic one), a toothpick, and a glass.  Push the forks into the sides of the cork.

They should be in the middle of the cork, directly opposite each other.  The cork will not be in alignment with the forks.  Try to have the forks at a 90 degree angle to each other, like this:

Push a toothpick into the end of the cork, on the side between the forks (be careful, the toothpick breaks easily, so be gentle). You will have something like this:

Experiment by balancing the toothpick on your finger.  It seems impossible, but once you find the right spot, the forks will just balance.  You can mark that spot on the toothpick with a marker, or just remember about where it was.

Place the balance point of the toothpick on the edge of a glass.  The forks should remain suspended on the side of the glass.  Pretty amazing!

Now, for the grand and very dramatic finale!  Take a match and light the end of the toothpick on fire (yes, I really did say to set fire to the toothpick – YOU, not your kids of course :-)  ).  The flame will move up the toothpick, burning it into nothingness.  The fire will stop when it reaches the rim of the glass.

Does the cork fall down?  NO!  It stays put, hanging by practically nothing on the rim of the glass.  You can even lift it off and place it back on, barely touching the rim, and the whole thing will balance.

Here’s a video I made of the toothpick burning (I have never put a homemade video on my blog before so I really hope it works).  Watch closely and you’ll see that my son tried to knock the whole thing off the glass at the end of the video but it just bobbed up and down and returned to its original position.  Very stable!

How does this seemingly magical “trick” work?  Warning:  science stuff coming up – feel free to skip to the next section if this is all “blah blah blah” to you.

The secret to understanding this experiment involves a study of center of gravity and pivot point.  The center of gravity is “the average location of the weight of the object.” Imagine balancing a see-saw.

But the center of gravity does not necessarily have to be on the object itself.  Here it is actually in the open space between the forks.  This means that, unlike a see-saw, the object is not balancing on its center of gravity (“CG”).  Instead it is balanced on a separate pivot point (the toothpick on the edge of the glass) away from the center of gravity.

We had to arrange the forks so that their mass was a bit lower than the center line of the cork in order to insure that the CG remained lower than the pivot point.  Since the CG is lower, if the fork assembly is displaced, the CG will be raised and gravity will pull it back to equilibrium.  You can see this in my video.  All balance toys have a CG that is below their pivot point.  (NOTE:  I am NOT a scientist! Any physicists out there may disagree with my terminology, etc., but I am trying to make this as simple an explanation as possible.)


Not wanting to use my good forks as permanent bird wings, I had to think of something else. A matching pair of thrift store forks would have been ideal, but the thrift stores were all closed today.  I ended up using a set of small screwdrivers that came from the bargain bin at the local hardware store, and that turned out to be not what my husband expected.  There were four screw drivers, so by using two corks, my daughter and I were each able to make a bird.

We stuck them into the sides of the cork at the appropriate angles (see above).  They were actually easier to get in there than the forks were.

TIP:  Test “fly” your configuration on a glass before proceeding further.  Adjust the screwdrivers (or forks) now if necessary to get it right.  I didn’t check mine before-hand and had to fiddle later after the feathers were on.

To create a good surface for sticking on feathers, I cut construction paper into a symmetrical wing shape.  By folding the paper and cutting double thickness (while keeping a portion of the fold intact) this was easy:

We then covered each screwdriver with a paper wing and stapled it so that the screwdriver was hidden inside.  Staple as close to the screwdriver as you can so the wings stay on.  It doesn’t matter if the staples are in the middle of the paper because you are going to completely cover the paper with feathers.

Paint your cork if you want to.

Next, glue on feathers.  We had “natural-looking” feathers and “fake-looking” feathers, both from Walmart a long time ago.  I opted for a colorful, fake bird.  My daughter chose to be more natural.  Elmer’s white glue didn’t work so well, so I broke out the hot glue gun and we began sticking on feathers.

I found an old jar to be a useful stand for our sticky birds while they dried, as well as for painting the underside of the cork.

After things have dried a bit, you’ll need eyes (googly or beads) and a beak of some sort.  We cut the tips off some new crayons with scissors to make our beaks and they made perfect beaks!  Glue them on with the glue gun.

If you haven’t already, carefully stick a toothpick in the back end of the bird.

Once everything is well dry, you can “fly” your birds on the edge of a glass.  If properly balanced, they’ll bob up and down when touched, but won’t fall off. PLEASE don’t try the flame trick since you don’t want to risk setting all the glue and feathers on fire!


If you did a balance project this week, then please link to your project post in Mr. Linky below. I really prefer links to project posts rather than blogs in general, so that readers will always be able to find your project no matter how far down it is buried in your blog. If you did not do a balance project, please do not link. Read more about how to participate here. We’d love to have you join us!


The theme for next week’s Unplugged Project will be:


Have fun!


Layered Life-Cycle Puzzles (Recommended Toy)

By , March 18, 2008 9:03 pm

Since my 2 year-old is obsessed with puzzles at the moment, I am always on the look-out for fun, educational, high quality puzzles that she might be able to do. A recent surfing expedition revealed these totally cool layered, life-cycle puzzles. They are made of wood and feature five separate puzzle pictures to complete. The mini-puzzles fit on top of one another in layers to show the life cycle of a butterfly (or frog, or duck).

The recommended age is 4 and up. As much as I’d like to claim that my genius 2 year-old could do these, she probably could not without assistance.  The big photo makes it look deceptively easy, but there are actually thirty pieces, five puzzles, and five layers.  Her older brother and sister might enjoy them though. Hmm…we’ll see. (It’s times like this that I really wish I homeschooled so that I’d have an excuse to buy these slightly pricey but really amazing-looking puzzles!)

These Beleduc puzzles are made in China of birch wood and meet or exceed “Specifications of European (EN-71) and American (ASTM) Toy Safety Standards:”

This butterfly puzzle is also made of wood, but the description offers less information (it costs less too):

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