SMMARTideas

SMMART SCIENCE: SUMMER BUBBLE BOMBS

It’s summer in Utah, so let’s take advantage of the good weather and make some bubbles outside. These bubbles are explosive so watch out!

Using baking soda and vinegar, you can pop a plastic bag with the power of fizz.

You will need:
¼ cup warm water
Measuring cups
Sealable plastic bags (make sure there are no holes in the bag)
Paper towels
1 ½ Tb baking soda
½ cup vinegar

· Cut a paper towel into a 5X5 inch square.

· Place 1 ½ Tb of baking soda into the center of the square and fold the paper towel into a “time-release” packet around the baking soda. With the baking soda in the center of the square, fold opposite sides of the paper towel over the baking soda to form a rectangle. Then fold the short sides down and over the center to form a square packet.

· Pour ½ cup of vinegar and ¼ cup of warm water into the plastic bag.

· Quickly drop the baking soda packet into the plastic bag and seal the bag before too much fizzing occurs. (Another method could be to seal the bag half way and then drop in the packet and close the seal. You could also put the packet into the bag, but pinch it through the sides of the bag so it doesn’t touch the vinegar and water until you seal the bag and then drop in the packet.)

· Shake the bag a little. Put it on the ground, in the sink or in the bathtub and watch as the bag puffs up and POPS!

Vinegar and baking soda react to form carbon dioxide gas. This is how quick bread or cake that use these ingredients can rise. The carbon dioxide bubbles in the batter are the result of a chemical reaction that combines the (acidic) vinegar and (basic) baking soda. Sometimes the recipe may call for another acidic ingredient, like buttermilk, sour milk or orange juice.Some quick bread recipes also use baking powder instead of or along with baking soda.

Baking powder is a combination of baking soda and an acidic catalyst like tartaric acid or calcium acid phosphate. Adding water starts the fizzing reaction going.

It might be fun to bake some quick breads together with your child. Observe the batter before it bakes and observe the air pockets in the bread after it is baked. Ask your child if he knows what may have caused the air pockets to be in the bread. Talk about how bread rises.You may want to change some (independent) variables to see what happens:

· What happens if you change the type of paper in which you wrap the baking soda?

· What happens if you use cold water or no water at all?

· What would happen if you use a bigger plastic bag, but the same amount of ingredients?

You can find this and other fun activities at:http://www.exploratorium.edu/science_explorer/bubblebomb.html

Lisa