Tuesday, January 11, 2011

Science of Fizz 2

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 included links to our YouTube videos. These links take you away from the blog and to external websites.

Lesson 10
Science of Fizz 2

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
Since we planned on using Alka Seltzer (seltzer) to make things go BOOM, as the kids arrived, we played Boom, Boom, Boom, by Jock Jams; Boom Boom Ain’t it Great to be Crazy, and of course the Alka Seltzer jingle – Plop, Plop, Fizz, Fizz, Oh What a Relief it Is.

As a fake-out, we put out some seltzer tablets with the snack
– a hint of the science to follow.
  The kids thought we were weird.
Soda Pop, How It’s Made by Arlene Erlbach.

- which describes how the ingredients of carbonated soft drinks are made, mixed, carbonated, and bottled. Includes simple recipes for making carbonated drinks at home.

5 minutes
Balooning Baby Bottle
This is a classic dating back to the original Mr. Wizard from the 1950’s.  You’ll need a plastic baby bottle, a “blind” baby bottle nipple (nipple without a hole in the tip), safety glasses, seltzer tablets, and water.  Put on the safety glasses.  Put 8 ounces of water in the baby bottle, drop in two seltzer tablets, and quickly cap the baby bottle.  Your kids may expect water to come shooting out of the nipple since they don’t know it has NO hole.  As carbon dioxide gas is being produced, the nipple will expand – filling with gas.  When the bubbling stops, invert the bottle, and allow the water to flow into the nipple and the gas to rise into the bottle.  Look at the graduations on the bottle to see the gas that was produced. Talk about why this cannot be an accurate way of measuring the true volume of the gas produced and see if kids can catch the potential error of non-standardized blind-nipple stretchiness.  Say that ten times fast!

Don’t go to a department store looking for blind nipples.  You won’t find them.  We found ours here of course. 

40 minutes
Seltzer Rockets
We got a film-developing booth to save us some film canisters (Fuji - clear ones where the lid fits inside), and we bought lots of seltzer tablets. First, we filled our film canisters with water.  We talked about the liquid properties of water.  We showed the children the seltzer tablet and talked about the properties of this solid.  Then we plopped the tablet into the water and let the children see the bubbles.  We asked them to predict how long the chemical reaction would last? We timed the reaction. We let them hold their hands over the cup and feel the bubbles.  We talked about the properties of gases.  We threw the liquid in the film canisters into the waste bucket. 

Then we demonstrated a launch. We refilled a canister about 1/3 full of water.  We broke off a ¼ piece of the seltzer tablet and dropped it into the water, quickly placed the lid on, and dropped it – lid down – into an empty paper towel tube, being careful to aim it away from the kids. In a few seconds the canister flew out at warp speed! 

When we combine bicarbonate of soda (solid) with water (liquid), it created bubbles of carbon dioxide (gas). So much gas was produced that the film canister couldn’t hold it all and the gas pushed the lid off the canister with such force that it was propelled out of the tube – POW!  Can you guess what the kids began shouting?

“Do it again!  Do it again!”  But repeating the same thing wouldn’t be science now would it.

So, we dawned our attractive and protective eyewear and headed outside for some real science. We brainstormed what variables we could change that might have an impact on the reaction time.  Then we changed ONE variable at a time, tested it, and recorded how long it took for the explosion to happen.  We changed the volume of water, the temperature of the water, the amount of seltzer tablet to use. 

You could make it a race – how many times can they do it in two minutes.  Sneak in some math – measure how high or far the lid flies.   What would happen if you capped the canister with a balloon?

40 minutes
CO2 Sandwiches

We gathered a measuring cup and spoons, vinegar, baking soda,
zip-type sandwich bags, and toilet/tissue paper.

We tore off a square of tissue paper, poured some baking soda into it and folded it - making a small packet.   
IT'S TIME FOR ANOTHER FIELD TRIP! We moved the club back OUTSIDE! We worked together to open the zipper-lock bags and measure a ¼ cup of warm, diluted vinegar into the bag. Then we slipped in the wrapped up packet of baking soda, and zipped the bag closed. We placed our bags on the ground and backed way.  Someone screamed, “Run for your lives!” 

We watched closely as the bags began to puff up…  get bigger and bigger until… BAM! 
Pop goes the baggie.  Sure, bubbling liquids and popping bags are fun, science?  So, we taught them the science behind the big bang.  Not THAT big bang.

When you mix vinegar and baking soda, a chemical reaction takes place producing a gas called carbon dioxide (CO2). If you really want to impress your friends, use the chemical names for each of the ingredients. Acetic acid (that’s vinegar) plus sodium bicarbonate (baking soda) produces carbon dioxide gas and water. 
The bag puffs up because the carbon dioxide gas takes up lots of space,
eventually filling the bag.
If there’s more gas than the bag can hold… KABOOM
 You can reuse the bags until they break. Wrapping the baking soda in tissue paper is a clever way of slowing down the reaction. It takes a few seconds more for tissue paper to dissolve so that the vinegar and baking soda mix.

How does the temperature of the water affect the pop? Repeat the experiment using cold water instead of warm water.  Try changing the amount of vinegar and baking soda you use to see how the reaction changes. Remember to only change one thing (variable at a time). For example, you can increase the amount of vinegar you use to 1/2 cup, but be sure to keep the amount of baking soda (one tablespoon) and the water (1/4 cup) the same. By changing only one variable at a time, you’ll be able to determine which ingredient has the most impact on the POP!  Wrap the baking soda in two or three pieces of tissue. How will this affect the reaction? What are 3 more variables you can change?

In this experiment we tried (from left to right) 1 tsp, 2 tsp, 3 tsp, and 4 tsp of baking soda.  Awesome results and an explosive grand finale’ for our day.

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