Posts tagged: science projects

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.

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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.

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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.

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BAKING SODA & WATER:

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

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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)

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, but here are a few informative links if you are interested:

The Myth of Persistence of Vision, by Joseph and Barbara Anderson

Lectures: Visual Perception 8 – The Moving Image

FIELD TRIP:

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.)

Homemade Anemometer – Weather (Weekly Unplugged Project)

By , October 4, 2009 8:35 pm

The theme for this week’s Unplugged Project was weather and the weather today was windy, VERY windy.  We decided to try making a homemade anemometer (device that measures wind speed) with the instructions that I found here.

You’ll need some stiff, corrugated cardboard, four small Dixie-type paper cups, a long sharp pencil with eraser, a stapler, scissors, a push pin and some modeling clay.

First cut the small rims off the paper cups using the scissors.

Next cut the cardboard into two strips of equal length.  Staple them together in the form of a cross.

Color one cup a different color.  Red or something bright would be easier to spot, but all we could find that would work on the waxy surface of the cup was a black Sharpie.

Find the exact center of your cross by drawing an “X” between the corners of the center portion like this:

Where the lines cross is the center and is where you will put your thumb tack.  (NOTE:  This step is easiest to do before you attach the cups).

Staple a cup to the end of each cardboard strip.  Make sure they are all facing the same way and are aligned perpendicular to the cardboard strips.

Push the pin through the center of the cross and into the eraser of the pencil.

Take your anemometer outside and stick it to a porch railing or table in a base made out of modeling clay.

Your anemometer should now spin in the wind!  (*SHOULD* – read note below!)

To check the speed, count the number of times the colored cup passes by you in one minute.  Obviously the more times it swings by, the faster the wind.  You can measure at different times of day to compare the wind speeds.

If you want to get really scientific you can calibrate your anemometer using your car.  Read the clever instructions for how to do it here.

* NOTE* – We discovered that although it was a very, very windy day out (55 mph gusts), the gusts were so variable in strength and direction that our anemometer didn’t spin very well (but it did blow off the railing once or twice!).

It worked much better inside with human-generated wind as you can see here in this very primitive video! (PS. Please ignore my messy house):

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If you joined in this week’s weather Unplugged Project, please link to your project post (not just your blog – we always want to be able to find your post) in the Linky below.  If you didn’t join in the Unplugged Project but think you might like to in the future, read more about how to participate here.  We’d love to have you!

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

Wheel

I must be in a “W” phase  at the moment.  I hope to see you next week!

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