Mr. O! A Video Blog from the Children's Museum of Houston » O Wow Moment Videos

Singing Glasses – Changing Tone

Mr.O — Fri, 27 Jan 2012 16:47:26 +0000

Like I didn’t get in enough trouble with Ms. Manners from the other Singing Glasses video, I decide to push my luck and explore the sound being created again in this O Wow Moments video, but time we’re going to look at tone.

First let’s talk about how to get a wine glass to “sing.” First, get a wine glass (kids, make sure to get your parents’ permission first before attempting this experiment; husbands – get your wives’ permission). While crystal makes excellent sounds, it is more fragile than glass and more expensive. So, since glass will work fine, I’d recommend using glass over crystal.

Once you have a glass, fill it about halfway with water, wet your finger and rub it around the edge. It takes a little exploration with how much pressure to use, but you should eventually get a great tone coming from it. It occurs because your finger makes the glass vibrate by constantly pulling a little, slipping, then pulling again.

Now that you can make a glass sing, change the amount of water in the glass – maybe pour some out or add in some more. What happens to the sound? Remember that the frequency, or tone, depends on how fast waves are passing a given point. Because sound travels at a specific speed, the frequency is affected by the wavelength, or the length of the waves you are creating. By changing the amount of liquid, you change the wavelength and therefore hear different tones.

Next step is to create a wineglass harmonica – a whole bunch of glasses filled to different levels to create different notes so that you can play songs. If you make one, please send us a recording! Personally, I’d love to hear a wineglass harmonica version of “Louie, Louie…”

Special thanks to our friends at Region’s Bank for making our O Wow Moments possible!

Singing Glasses and Sympathetic Resonance

Mr.O — Wed, 25 Jan 2012 20:21:15 +0000

Miss Manners definitely will not approve of this video or its sequel, but science (and O Wow Moments) must not be held back!

In this episode, we’re going to explore sympathetic resonance. But, before we can do that, we first need to explore the science of making glasses sing. It isn’t that hard to do – get a wine glass (kids, make sure to get your parents’ permission first before attempting this experiment; husbands – get your wives’ permission). While crystal makes excellent sounds, it is more fragile than glass and more expensive. So, since glass will work fine, I’d recommend using glass over crystal.

Once you have a glass, fill it about halfway with water, wet your finger and rub it around the edge. It takes a little exploration with how much pressure to use, but you should eventually get a great tone coming from it. It occurs because your finger makes the glass vibrate by constantly pulling a little, slipping, then pulling again.

Once you have your tone, get a second glass and repeat, this time adjusting the amount of water until the tones are as close as possible to the same. Remember – the key is the TONE to be the same, not the water level.

Sympathetic resonance is where the sound waves generated by one glass travel through the air and interact with the second glass to make it vibrate as well because they are “tuned” to the same frequency, or tone. You can see these vibrations by placing a toothpick or a small piece of straw on top of the second glass then making the first sing. How far away can you get and still make the second glass vibrate?

By the way, this is also how opera singers, according to legend, can use their voice to make a crystal wine glass break. They hit the same resonance, but at such high volume that the glass shatters. The first people I know to have recorded it on video were the Mythbusters as shown on this video. They had vocal coach Jaime Vendera break it which you can see him repeat on this video he posted afterwards.

Special thanks to our friends at Region’s Bank for making our O Wow Moments possible!

Party Hat Symmetry

Mr.O — Fri, 30 Dec 2011 20:39:00 +0000

So it is New Year’s eve…and we don’t have party hats at the Children’s Museum of Houston! How can we solve this problem? Well, obviously we could go buy some hats from a party store, but that would take time and money. Besides, why spend money on something cheap that someone else made when you can make it yourself using things already in your house!

Of course, we need something besides just materials. We need know-how. We need…math! Yes, that’s right, math. It isn’t just for adding and subtracting; math is also shapes and rotation. Math includes symmetry! So we’re going to use symmetry (and measurement) to cut out the shapes we need to assemble our hats!

What You Need:

Wrapping paper, as festive as you want
Scissors
Ruler
Pen/Pencil
Stapler

What to Do:

Cut out a 16” x 24” piece of wrapping paper
Lay it on the table with the color side up in landscape
Fold it in half left-to-right (hamburger fold)
Fold it in half again, this time bottom-to-top
Fold the top left corner to the bottom edge, creating a triangle
Measure 7½ inches from the corner along the slant and bottom and mark
Draw an arc between the two marks and cut along the arc
Open up paper to the halfway point (roughly a half circle)
From the midpoint on the bottom, measure 4 inches along each of the three creases and cut
Finish unfolding and repeat step 9 for the two uncut creases
Begin top by repeating steps 1-5
Fold the top layer of the triangle back up to the slant
Measure 4 inches from the corner along slant and bottom and mark
Measure 5 inches from the corner along the middle line and mark
Connect the three points and cut out diamond shape
Unfold completely
Lay the two shapes on top of each other color side out with the smaller one on top
Staple the points of the stars to the points of the flaps

What’s Happening?

When you fold paper more than once and make a cut, you are most likely creating rotational symmetry. In biology, we call it radial symmetry, like you would find in flowers, starfish, octopi, snowflakes, etc. Basically, it means that if you turn a shape around a central point, the same parts of the shape appear over and over.

So, if you follow the same basic folds each time, but make your cuts different, you’ll get different shapes, but all with rotational symmetry. So create your own special shapes to make your party hat unique to you.

HAPPY NEW YEAR!!!!

Special thanks to our friends at Region’s Bank for making our O Wow Moments possible!

*This activity is based on the Instructable “Cool Way to Make a Paper Hat”

Santa-Pults

Mr.O — Sat, 24 Dec 2011 12:15:10 +0000

Breaking news from the Children’s Museum of Houston – we just learned that insurance companies are no longer providing coverage to roof damage due to hooves and sleigh rails, thereby preventing Santa from landing on our roofs for easy chimney access! Fortunately, we do have a potential solution – projectile motion!

Projectile motion is motion in two planes – the horizontal and the vertical. By controlling the angle at which a projectile starts and the amount of force provided, we can control its travel. And what better way to control angle and force than to build a catapult! But not just any catapult…a SANTA-PULT!

So go digging through the odds and ends around your house. There are three basic types of materials you’ll need:

Force Generating Materials – springs (like in clothespins and clipboards) and elastic materials (like rubber bands and plastic spoons) can be used to provide the force your object needs
Lever Arm Materials - this is usually a stick that is attached to the force generating material to help increase the force and give you a place to put your projectile. Rulers and craft sticks work well as lever arms
Frame Materials – this is the body of the catapult and helps define the angle at which the projectile launches. Cardboard, foamcore, sticks, and many other things work well. This is also where I put the materials that hold everything together like tape, rubber bands, twist ties, binder clips, etc.

So design, engineer, build, and test your Santa-Pult, although I recommend a stand-in for Santa and your chimney until you get it right. A box works well for a chimney and a lightweight ball works well for your Santa stand-in. However, I do recommend against testing it around anything breakable. Good luck and have fun!

Special thanks to our friends at Region’s Bank for making our O Wow Moments possible!

Ring Wing Glider

Mr.O — Mon, 19 Dec 2011 21:00:30 +0000

So we’ve done a few prior O Wow Moments here at the Children’s Museum of Houston on aerodynamics and planes like Blow Bernoulli Blow and Air Control. Basically, there are four forces that act on a plane:

Thrust – this the the forward force on a plane, ususally by an engine or, with paper airplanes, a throw
Lift – this is the upward force that allows a plane to fly, usually caused by the air under the wing pushing up on it due to the shape of the wing
Drag – this is basically friction, the force opposing the thrust on the plane which will cause it to slow down
Gravity – this is the force pulling a plane down

The key for a plane to fly is whether the thrust provided can generate sufficient lift to overcome gravity. So long as the design does that, it doesn’t matter what shape the wing takes.

Take ring wing gliders, for example. These gliders use hoops at either end to give them the lift they need to glide. So what kind of ring wing glider can you design?

Special thanks to our friends at Region’s Bank for making our O Wow Moments possible!

Mini Rockets

Mr.O — Sat, 10 Dec 2011 12:15:52 +0000

We’ve explored the Launch Cage in Invention Convention at the Children’s Museum of Houston several times in the past, mostly as an example for physics. But this time my assistants wanted to know how they could do rockets at home quickly and simply. Well, we’ll make sure to do an episode soon on how to recreate the exact experience as our Rocket Launchers at home, but for now we went with something a little faster – mini rockets!

These little rockets can put on quite a show. They’re also very quick to make and only use supplies that you are bound to have around your house: straws, tape, and post-it notes. Plus, they are a great way to study Newton’s Third Law of Motion! But PLEASE don’t aim them at anyone – we don’t want anyone hurt doing science!

Special thanks to our friends at Region’s Bank for making our O Wow Moments possible!

Stick Chain Reaction

Mr.O — Sat, 03 Dec 2011 12:15:45 +0000

I don’t normally watch reality TV or variety shows, so I missed out on the Kinetic King phenomena on the last America’s Got Talent. I only learned about it while doing research for this video. I actually came across this idea of using jumbo craft sticks to create chain reactions from some home movies of things that kids had made, which made me think that it was something that the Children’s Museum of Houston had to highlight on an O Wow Moment episode.

So, while I do show you how to do the cobra weave pattern to create a stick chain reaction, we also take some time to discuss the science behind why these reactions work – that wood is, in fact elastic, meaning it can deform and snap back to its original shape. Because wood is elastic, it can store energy in the form of potential energy when it is bent. Once released, that potential energy turns into kinetic energy.

When you make a long string of sticks properly woven, you have lots of potential energy stored waiting to be transformed into kinetic. However, the sticks have to be released in order, so rather than them going off all at once, they go off in a chain, like a row of dominoes falling.

And, for the Kinetic King (aka Tim Fort) – dude, you got robbed! Awesome talent – keep on making Rube Goldberg-esque creations.

Special thanks to our friends at Region’s Bank for making our O Wow Moments possible!

Frustration with Fractions

Mr.O — Tue, 29 Nov 2011 15:47:55 +0000

We have an exhibit in the Children’s Museum of Houston called Restore the Power, a part of the Cyberchase: The Chase Is On! exhibition based on the PBS Kids show Cyberchase from Thirteen WNET New York. In it, you have to use fractions to put back together rods and restore the power to a component. But some kids and parents are a little hesitant to explore the component the moment that they see fractions. Why? Well, often, people have had a negative experience when they first encountered fractions because they didn’t really understand the basics of fractions. And, when someone doesn’t understand the basics of fraction, they suffer from fraction frustrations. So, to help, let’s all go back to basics.

Often, the best way to learn about fractions is to directly experience them – manipulate them and try to figure out how they interact and compare with each other by directly comparing them. How many thirds and sixths does it take to be equivalent to a half? Let’s find out by using fraction cards!

Fraction cards are a quick and easy way to start exploring the idea of equivalence as well as other manipulations of fractions. They are cheap to make (all you need is construction paper, markers, and scissors) and are very useful. Plus, there are lots of games you can play to help make manipulating fractions make sense and relieve your fraction frustations. So check out the video and learn how to make your own set today!

Special thanks to our friends at Region’s Bank for making our O Wow Moments possible!

Tippy Towers

Mr.O — Sat, 19 Nov 2011 12:15:51 +0000

I loved building with Lego Bricks as a kid – spaceships were one of my favorites! My brother, however, found that building with Legos wasn’t exactly his forte. However, annoying me DEFINITELY was something at which he excelled. So every time I pulled out the Legos (a.k.a. “dump out all the Lego pieces onto the floor in a giant pile that wouldn’t get cleaned up for days”), he would build the “Junkyard robot” – a creation made up almost entirely of a pair of wheels and a giant stack of 2×2 bricks, one on top of the other. He would then roll his robot on top of what I was creating or have the robot “take” some of the Lego bricks I was using and hide them back into the giant pile.

Of course, he’d also continue to build his robot taller and taller until it could no longer balance and tip over (or break in half). In the video, my assistants also build a giant tower (this time of Duplo blocks) in the Invention Convention exhibit at the Children’s Museum of Houston which also fell. In both cases, the issue wasn’t how tight they put it together, but that the center of mass was so high that the towers were just unstable. But, by building a wider foundation, the tower becomes more stable as the center of mass shifts downward.

Take our cup tower challenge and see if you can find a correlation between the width of the base and how tall you can build the tower. Good luck!

Special thanks to our friends at Region’s Bank for making our O Wow Moments possible!

Well Honk My Goose

Mr.O — Sat, 12 Nov 2011 12:15:34 +0000

Is there anything more wonderful, more melodic, more relaxing, than listening to quiet, gentle music played by professionals?

Well, that isn’t going to happen in this O Wow Moments episode. And it DEFINITELY isn’t happening with the goose honker! My assistants were curious about how we can generate vibrations to create sound. While we know we can pluck strings, like the ones in the Play That Pitch exhibit at the Children’s Museum of Houston, were there other ways to make sounds with strings?

Well, we created this homemade “instrument” (and I use that term very loosely) which, while definitely and clearly demonstrating how to vibrations create sound, you definitely aren’t going to be playing Mozart on it. On the bright side, it is GREAT at annoying siblings! Have fun making your own!

Special thanks to our friends at Region’s Bank for making our O Wow Moments possible!