Wednesday, January 5, 2011

Science of Fizz 1

Every week, Madison (my 10-year old daughter) and I teach a 1.5-hour afterschool science club for K-2nd graders.  Each week she helps plan the lesson and then we write the blog about what we did. 

We have provided links to the books we used to sneak in some literacy.  We learned most of the science experiments and activities from Steve Spangler (awesome speaker and science guy extraordinaire).  We have included links to his science supplies, experiments, and videos.  We have also provided links to our YouTube videos. These links take you away from the blog and to external websites.

Lesson 9
Science of Fizz
Science Standards Addressed:
  • Describe the characteristics of the 3 states of matter (solid, liquid, gas).
  • Know that air takes up space and exerts a force.
  • Know that when substances are combined they may create a new substance with different properties.
  • Identify forces that produce motion in objects.
Plus we snuck in some speaking and listening standards like asking questions, expressing ideas, following multi-step directions, and participating in discussions.

10 minutes
As the children arrived we played the songs Tiny Bubbles, by Don Ho and the Coke jingle – “I’d like to buy the world a Coke!

In addition to the healthy stuff, we had a special treat of fizzy soda can candy
 – a hint of the science to follow.

To sneak in some literacy, while we ate Madison read
Wallop and Whizz and the Bottle of Fizz, by Philip Hawthorn
 - a colorful and funny book, a mixture of good stories and good rhyming. The story is brought to life by the illustrations.

Sewer Maggots
To engage their emotions, we created an imaginary situation.  I told the kids that my dad got this liquid out of the toilet and it was lucky that no one had flushed.  Yuck! Then I told them that scientists had genetically engineered some special little critters that can clean the waste from contaminated water - sewer maggots!  We dumped a few of these bugs into the toilet “water.”  

Immediately, the sewer maggots seemed to come to life with lots of bubbles and sinking and floating. 
After a while, the bubbling slowed and we asked the kids if they thought maybe the water was safe to drink.  "NO WAY NEVER!" We smelled the liquid and made a disgusting face (for effect) and took a sip!  This gives “Gag a Maggot” new meaning. 

Then we both acted like it was actually pretty tasty and took some big gulps.
That got lots of gross faces from the kids.
After that we told them the science of the sewer maggots:

The liquid was actually Mountain Dew and the maggots were just raisins.  When we dropped the raisins into the liquid, bubbles began to form on the numerous nucleation sites on the raisins.  These bubbles they add a lot of volume to the raisin, but little mass.  Think of the bubbles as tiny life jackets – the bubbles achieve positive buoyancy and rise to the surface where the bubbles pop and the raising sink. 

Rising and sinking will continue until the soda is flat – no more carbon dioxide.  Attach a Fizz-Keeper and pump up the pressure.  You will notice less bubbling and the raisins will remain on the bottom of the bottle.  Unscrew the Fizz-Keeper and the rising and falling will start up again. 

Lava Lamps
We gave every child a small water bottle that was half full of water.  They added food coloring, and then we filled it up the rest of the way with vegetable oil.  We gave each child a little piece of an Alka-Seltzer tablet. 
On the count of 3 we all dropped it into the bottles and the tablet started bubbling and little globs of colored liquid started growing upwards – groovy baby – just like a lava lamp.
After Ooh’ing and Aah’ing for a while, we told them the science of it.
The water molecules don’t mix with the oil molecules – “oil and water don’t mix.” The food coloring is water-soluble, so it only mixes with water, not oil. It does not color the oil. 
Oil is less dense than water, so it floats on the surface.  That’s a good thing when we have a bad oil spill or else all that oil would sink to the bottom of the ocean. The Alka-Seltzer reacts with water to make tiny bubbles of carbon dioxide gas. 
These bubbles attach themselves to the blobs of colored water, like tiny life jackets, and they float to the surface. When the bubbles pop, the colored blobs sink back to the bottom
 – just like the sewer maggots.

You’ve probably seen this done before, but we didn't JUST do the Mentos geyser thing, we did what scientists do - we experimented.  

We got a 2-L bottle of soda and placed it next to a brick wall (so we could use the rows of bricks like graph paper and count the number of bricks that the geysers reached).  
We attached the geyser tube and on the count of three two of the kids pulled the string that released the Mentos into the soda – and whoosh! Dad let us taste some of the soda left in the bottles – minty but flat.

As the soda sprang out of the bottle we counted how many rows of bricks high the soda went up.  Then we created some actual experiments.  We asked the kids to think of some things that might change the reaction.  When they thought of something – a variable – we could change, they predicted what they thought the change might be.  We decided to conduct an experiment comparing different numbers of Mentos.
We tried 7 Mentos (on LEFT) vs. 3 Mentos (on RIGHT). 
We decided to compare different types of sodas.  We tried Diet Coke vs. Regular Coke; Diet Coke vs. Diet generic soda; Diet Coke vs. Diet Sprite, etc.  We only did 1 regular/non-diet soda because the sugar gets everything sticky and attracts ants!

Finally we tried cold Diet Coke (that had been sitting in an ice bath – on LEFT)
vs. warm Diet Coke (that had been sitting in a warm-water bath – on RIGHT).
When we describe the science of this – we use the kids in the swimming pool analogy.  We ask them to imagine that they are some of HUNDREDS of kids in a swimming pool – and that all of the kids want to get out of the water – they are tired, been in the pool for days, and just want OUT.  But there are NO ladders and no way out of the water.  When we drop the Mentos in (each one having hundreds of nucleation sites that help Carbon Dioxide bubbles form) it is like putting a thousand ladders into the pool… EVERYBODY OUT!  When they ALL leave through the tiny opening in the geyser, the kids/bubbles come shooting out of the pool!
All of the parents were snapping pictures when they arrived to pick up their kids.
Nice grand finale’ to end the day!

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