Saturday, March 29, 2014

Filling a Vacuum (Playing With a Syringe)

Its been far too long, but the Science Kid was on a little vacation.  But she's back and ready for SCIENCE!

A vacuum is simply an absence.  No water; no air; no nothing!  Even deepest darkest space isn't a vacuum.  As one would travel through interstellar space, the hydrogen atoms, moving at only a few degrees above absolute zero, would bump into your spaceship and cause some serious problems.  Even though a vacuum is only a theoretical construct, we can get pretty darn close here on planet Earth.  When you drink through a straw, you are creating a vacuum.  When you kiss someone on the cheek, you are creating a vacuum.  When you clean your carpeting...you get the idea.
By removing the air from an enclosed space, a virtual vacuum is created.  We can do this with our mouth, but that takes quite a bit of effort.  We can use a pump, but requires some very strong seals and lots of people power.  To create a vacuum in our lab today, we used a 1mL syringe.

Note:  Most pharmacies will carry a variety of syringes.  They are common for giving babies medicine, among other things.  You can even sweet talk your doctor or vet into giving you a few to play with.  However, I can't stress this enough.  Make sure that your SK knows that any syringes found ANYWHERE except the lab are not for science.  This is probably a bigger issue for City SKs than Suburban or Rural SKs, but you never know...

SK asked if you could wear a hat in the lab..That was a great idea!  It is very important to keep our hair (and the sun?) out of our eyes, so Goggles and hat it is.

We started with a simple bowl of water.  We talked about what was in the syringe when we pulled out the plunger.  The first answer was nothing, of course.  But we pulled the plunger out with the tip of the syringe on SKs hand.  When we pulled it off, it made a popping sound!  She determined that if the plunger was pulling something, it would be pulling in the air.  If the air goes in when we pull, the air comes out when we push.  We had some fun blowing little puffs of air into each other's faces!

Next, we used our bowl of water.  First, we pushed the air into the water and it made bubbles!  Without prompting, SK pulled in the water instead of the air, but put it right back into the bowl.  I'm not sure if she saw the water go in, so I took my syringe, pulled in the water and squirted it into the bowl from above.  Without missing a beat, she gave it a try.  We talked about how the water stayed inside of the syringe, even when it was out of the bowl; the air was pushing the water at the tip.  The only way to to get the water out was to push the plunger.
After we played a bit, SK wanted food coloring...again.  So we put in some drops, stirred, and kept squirting each other!

This was a pretty easy experiment to put together.  What sorts of modifications could we make?
  • The food coloring was a good addition, because we could more easily see the water in the syringe.
  • Straws could be used to compare the process to the syringe.  The old finger on the end of the straw operates on the same property.
  • Even a water-squirter as used in a swimming pool could work!  Unfortunately, March in Chicago isn't a good time for water sports.
What sorts of things did you do with your SK?




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