Two-Stage Balloon Rocket - Take Two

The children got up this morning, ready to give our two-stage balloon rocket a second go.

First though, we decided we better make sure our basic balloon rocket set-up was good, so we set up the experiment with a single, inflated balloon, taped to a piece of straw, threaded onto piece of string, pulled tight horizontally.

When we let the balloon go, it spiraled in place around the string...

...and broke loose from the tape, without moving the straw forward on the string.

We thought, perhaps, we had the balloon taped too tightly to the straw.  So, we modified our tape...

...to create a gap between the balloon and the straw.

This time, when we let the balloon go, it still spiraled slightly, and the balloon still broke free of the tape...

...but not until it had moved the straw all the way down, and bounced off E's hand, at the end.

Satisfied, we repeated the single balloon experiment, with the string tilted upward, like we had had it for our first two-stage attempt.

Again, the balloon carried the straw to the end of the string, before breaking loose, and continuing on another few feet beyond E.

Using our modified tape design, we added the half of the Styrofoam cup, and a second straw with tape...

...for a second (first stage) balloon.  Put together correctly, the second balloon is supposed to be inflated enough to hold the neck of the first balloon shut against the edge of the cup.

Our first balloon was quickly deflating, and it was impossible to release them both at the same time.

We tried blowing more air into the second balloon, to make it bigger, but only succeeded in breaking open the cup.

I reluctantly agreed to sacrifice one of my sturdier, waxed paper, coffee cups.

We added some tape to the cut edge of the cup, to protect the balloon, and found that with a sturdier cup, it was possible to keep both balloons inflated, holding only the neck of the second balloon.

Unfortunately, when we let the balloon go...

...both balloons deflated, and broke free of the tape, without moving the straws forward.

We tried securing the first balloon to its straw, with extra tape...

...which did result in a nice break-away of the first stage of our rocket...

...but not only did the primary balloon "engine" fail to propel the rocket forward at all, the two balloons stuck together.  So, as the first balloon deflated, it pulled on the second balloon...

 ...keeping it from moving forward either.

Finally, we tried taping the cup to the second, or primary balloon (I know it sounds confusing - it's the primary part of the rocket, but the second balloon installed), to the cup.

This kept the cup, and second balloon from breaking away...

...but did allow the first balloon to move forward.

The idea of course, is to get the primary balloon to give the rocket a little push forward, then break away with the cup, allowing the secondary (or front) balloon to continue on even farther.  We are still missing the initial push, and proper breakaway.

However, it was about then, that a butterfly flew by the window...

...and the hunt was on.

There are days that almost unschooling a family of six feels a lot like a productive sort of ADD.

Two-Stage Balloon Rocket - Take One

I saw this experiment sketched out on a sample page from The Critical Thinking Co.'s Developing Critical Thinking through Science, Hands on Physical Science workbook.  It's basically just the traditional balloon rocket, with the twist of a second balloon added, to simulate a two part rocket.

We're working through a wind power science kit, and I thought, being air powered, the experiment might fit in nicely as a quick "wow" type project, before bed.

We started out with a couple of balloons, a Styrofoam cup, a straw, a ball of string, tape, and scissors.

Following the Critical Thinking Co.'s instructions, we cut the cup in half, and discarded the bottom half.

Then, we cut two short pieces from the straw...

...and threaded them onto the string, making sure they could slide freely, up and down the string.

We blew one of the balloons up, and pulled the untied neck through the cup, pinching it to keep the air in the balloon.

Then, we placed the second balloon into the cup, from the other side..

...and blew it up, until it was large enough to hold the neck of the first balloon in place (easier said than done).

We taped the straws to the balloons.  I probably should have mentioned to the children that they needed to be in a straight line, before I told them to quickly tape the straws on.

Once we got the straws straightened out, I handed off the camera (meaning, get ready for some very blurry shots), and had one of the children hold the end of the string on the side of the first balloon, as high in the air as they could, while another of the children held the other end of the string, tight to the floor, as I...

...prepared to let go of the second balloon.  The idea was for it to propel the rocket a little way up the string, and as it deflated, release the neck of the first balloon, which in turn would let out its air, propelling the rocket even farther up the string.

Unfortunately, the second balloon was deflated before I could even pull my hand away, and the front balloon emptied nearly as fast...

...the straws didn't move on the string at all.  All that really happened was that as the balloons got smaller, the cup slipped down over them, and fell off the bottom of the string.  Not quite the "wow" I was going for.

It was getting late though, so I sent the children off to bed, mulling over the problem of our failed project.  Hopefully, they wake up fresh in the morning, with ideas for improving our second attempt.

"I'm quite beside myself."

A Butterfly's Eye View - UV Nectar Guides

While identifying the Queen Alexandra's Sulpur butterflies in our backyard, we read that they are also sometimes called UV Sulphur butterflies. The male butterflies reflect UV light to attract females - or something like that.  We didn't fully understand everything we read, but we wanted to check it out.

I made a quick butterfly net out of a hanger, and some netting, that came around our oranges, for the children...

...and sent them on a butterfly hunt.

Once we captured a specimen (and by we, I mean me - much to the amusement of our neighbors, I'm sure), we placed it into an empty fish bowl...

...so we could shine a UV flashlight onto it, in a dark room.  It sort of glowed, but not in anyway that was impressive, so I'm thinking there's more to it, than we were seeing or understanding.  Still, it was worth a try.

After we released our butterfly back into the wild, and watched it fly away, stunned but unharmed...

...we decided to take a look at one of the dandelions it was frequenting.  This time our UV light revealed something interesting.  The florets on the outer edge of the flower turned a light pink, while the center of the dandelion remained dark yellow.  After a little more research we found out this is called a nectar guide.

Butterflies, like bees, and a number of other insects, don't see the color red, but do see some UV light.  When viewed under a UV light, many flowers have patterns that indicate nectar, and draw insects in like a bullseye. 

We won't be looking at dandelions the same way again.  Who knew there were so many fascinating scientific discoveries waiting in our backyard?

Sources:
Wikipedia - "Ultraviolet Communication In Butterflies" and "Colias Alexandra"
Boston University - "Ultraviolet Patterns in Flowers, or Flowers as Viewed by Insects" by Richard B. Primack. This is a good one to read, if you're wondering how scientists know that insects can see UV light and not red.
PBS Kids - Fetch!: season 4, episode 13, "Is it a Bird? Is it a Plane? It's...Ruffmanman!"

Queen Alexandra's Sulphur Butterflies - Unschooling Science Strikes Again

While we were out trying to get a peek at the baby ground squirrels, the kids noticed the small butterflies, that I had been calling cabbage whites, didn't look as white as the ones we're used to seeing.  In fact, they looked to be more of a florescent yellow-green.

Naturally, we had to take a closer look.

And happily for us, a couple of the little guys were good enough to fly in and land on a dandelion for just long enough for us to sneak up, and get a few good pictures...

...to label, like with the honey bee.

...and identify, with the help of the Montana Field Guide...

...after a short detour to BrainPop.com for a review of animal classification (you have to have a subscription to view the BrainPop video, but you can find the simpler BrainPop Jr. video on animal classification, here, on YouTube).  I'm not trying to sell you on a subscription service, BrainPop just happens to be our go-to site for easy to digest bits of information, and in this case was great help as we navigated through the Montana Field Guide:

• from Kingdom - Animals - Animalia
  • to Phylum - Insects, Springtails, Millipedes - Mandibulata
    • on to Class - Insects - Insecta
      • and Order - Butterflies / Moths - Lepidoptera
        • and Family - Orange-tip / White / Sulphur Butterflies - Pieridae
          • and finally to Species - which turned out to be a Queen Alexandra's Sulphur - Colias alexandra rather than a Cabbage White - Pieris rapae - same family, but different butterfly.

A little more research revealed some interesting facts about this particular butterfly, that led us on another adventure involving a homemade butterfly net, a fish bowl, and a UV flashlight, that I hope to tell you all about...

...tomorrow.

It's great to be a homeschooler.