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Questions to Ask
For this exploration, the children can smell and taste the ingredients.
Ask them to describe the various odors and tastes. Are they reminded
of anything else they know? What does the baking soda look like?
What does it feel like? If you could not smell the vinegar, what
might you think it is?
When the bag expands, ask the children what is causing this change?
What does the blown up bag remind them of?
Tips for Less Mess: You might want to cover the table or work area
with newspapers or towels. Keep paper towels and a garbage bag on
hand for clean up.
Science Connection
When the vinegar and baking soda are mixed, a chemical reaction
occurs, forming carbon dioxide gas. The gas bubbles out of the liquid
and builds up enough pressure to inflate the bag. Some gas bubbles
are also trapped in the mixture and form a foam.
The process of dissolving the baking soda removes heat from the
system. You may notice that the mixture feels colder.
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Why
To examine the three phases of matter all in one bag
What You Need
Small paper cup
3 Teaspoons baking soda
Sandwich size zip top bag
3 Tablespoons vinegar
What to Do
Ask the children to measure the baking soda and place it in the
cup. Next, measure and pour the vinegar into the bag. Carefully,
place the cup of baking soda in the bag of vinegar. Seal the bag
without tipping the cup. Once it is securely sealed, shake the
bag to mix the ingredients. What happens?
Vocabulary
Carbon Dioxide (CO2): Is a common odorless, colorless gas that
is produced from respiration. The tiny bubbles in soda beverages
are filled with carbon dioxide.
Gas: The state of matter in which the molecules have enough energy
to overcome the forces that attract them together. Gas molecules
become evenly distributed throughout the space that contains them.
Liquids and solids can pass through a gas.
Inflate: To fill something with a gas; tires and balloons are
inflated with air.
Liquid: Feels wet; takes on the shape of the container it is in.
Solids can pass through a liquid.
Pressure: A force exerted on an area
Solid: Neither a gas nor liquid. Solids cannot pass through each
other. Solids feel hard compared to a gas or liquid.
Try This
Can the children demonstrate what happens to the bag by using
a part of their bodies? How about their mouths?
Add a peanut or raisin to the bag prior to shaking it. What do
you think will happen? What else would the children like to place
in the bag?
Try using a larger bag and color the vinegar with a few drops
of food coloring. Do you still get the same effect?
Mount the inflated bag on the refrigerator door. What do you think
will happen? Examine the bag periodically and draw pictures of
it.
Place the bag in the refrigerator for an hour or so. What do you
think will happen? Is this different from what happens if you
leave it at room temperature for the same length of time?
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