Posts tagged: science

Watch the Perseid Meteors Tonight

By , August 14, 2010 2:53 pm

Last night I woke my two oldest children up at 2:30AM.  I led my confused and sleepy babies out onto the golf course behind our house armed with a flashlight and a blanket.  I spread out the blanket on the cool, damp grass of the fairway, we all laid on it facing northeast … and hoped that the sprinklers would not go off! Lol!

The children were astonished by what they saw – shooting stars, lots of them!  We also saw the Milky Way and several satellites marching in line across the night sky.

Our fabulous unplugged (and free!) show was the annual Perseid Meteor Shower.  The peak was the nights of August 12 and 13th, but you might still be able to see a pretty good display through the 22nd (especially if you are lucky enough to live in a low ambient light area like we do).  Just look to the northeast after midnight.

PS.  Most visible in the Northern Hemisphere, sorry!

LINKS:

EarthSky’s Meteor Shower Guide

Excellent Perseid Meteor Shower Expected

How-To: Photographing the Perseid Meteor Shower

Perseid Photo Gallery

For another of our astronomy adventures, you might like to read: The Moon Unplugged? Not For Me!! (Part 1) and Mom Unplugged vs. Evil Sleepy Poser Mom – Lunar Dilemma Part 2.

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(PHOTO:  I wish I had taken this great Perseid photo, but it is the work of Mila Zinkova.  License information can be found here.)

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  We originally made up our own version out of black poster board, an old CD, a small lazy susan, and lots of tape.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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Sound – Fun Links (Weekly Unplugged Project)

By , September 14, 2009 10:41 am

I had all kinds of thoughts churning about in my head for this week’s Unplugged Project theme:  sound.  A science experiment, a game involving sounds, making a musical instrument.  But this weekend we were so naturally unplugged, that we didn’t have time for an Unplugged Project!

Soccer, a concert fundraiser for our school (a concert involves music which is sound, right?), homework, and then a lazy rainy and cool Sunday afternoon spent reading on the sofa in front of the fire.  That wonderful first fire of the season.  Fall is definitely on its way.

This week I offer instead, a few quick links related to sound.  Not terribly “unplugged” perhaps, but hopefully useful for someone.

Neuroscience for Kids – Hearing Experiments:  Fun activities and experiments for children arranged by grade levels (Kindergarten – Grade 12).

San Fransisco Exploratorium – The Science of Music, Headlands Experiments: What do you get when you mix a tunnel, a metal gate, two musicians, and a physicist?

Hark the Sound Computer Game:  A game designed for visually impaired children that includes games involving naming, categories, math, words, and Braille.  There is also the possibility of easily modifying the existing games to suit your child’s needs, or to create your own new games.

Exploratorium Online Sound Games:  Play “Pong” with your eyes closed (sound guides you to the ball), analyze bird calls, create your own soundscape, do “sound jigsaw puzzles” and play a sound memory game.  Not unplugged, but really neat activities!

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If you did a sound Unplugged Project this week, thank you!  As usual, please link to your post in the linky below.  If you didn’t do a sound project, but would like to join in, then please do not link but read more about the Weekly Unplugged Project here.  We’d love to have more people!

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

Feathers

Be creative and have fun!

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Science – Weekly Unplugged Project

By , April 19, 2009 9:36 pm

Oh, I had better get this up now before Turnoff Week starts tomorrow and we are all supposed to try not to be on the computer!

The theme for this week’s Unplugged Project was science.  I actually have something to post about science, but I didn’t get to it today.  Perhaps I will post tomorrow, but I’ll try and post quickly!!  I’ll link to it in Mr. Linky below if I get to it.

If you have a science Unplugged Project to post, please link to your project post in Mr. Linky below.  If you didn’t do a science project, but want to join in in the future, please read more about the Unplugged Project here.  We’d love to have you!

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

Yellow

Have fun!

PS:  It’s not too late to join in the Turnoff Week Blog Challenge for a chance to win a $10 Amazon gift certificate (Turnoff Week is April 20 – 26).  Read here for more information!

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