Tuesday, October 4, 2011

Exploring Weather with Steve Spangler

In a comment on our blog, Mrs. Malkoske told us about a Scientist, Steve Spangler, she thought we should check out. He posts videos of experiments including one on creating a cloud in a bottle. This is a little different than the one we tried but, it works! Here it is:

Our reflections:
It was really cool how it turned all white. It was because it got all pressured and when he took the thing out it went "poof", like it turned white. -Rachel

It was cool when the could appeared because when we did our experiment it failed but when they did theirs it secceeded. -Kaitie

The cloud and smoke disappeared inside the bottle when the pump changed the pressure. -Michelle

How does it work? Explanation from Steve Spangler Science
Even though we don't see them, water molecules are in the air all around us. These airborne water molecules are called water vapor. When the molecules are bouncing around in the atmosphere, they don't normally stick together.
Pumping the bottle forces the molecules to squeeze together or compress. Releasing the pressure allows the air to expand, and in doing so, the temperature of the air becomes cooler. This cooling process allows the molecules to stick together - or condense - more easily, forming tiny droplets. Clouds are nothing more than groups of tiny water droplets!
The reason the rubbing alcohol forms a more visible cloud is because alcohol evaporates more quickly than water. Alcohol molecules have weaker bonds than water molecules, so they let go of each other more easily. Since there are more evaporated alcohol molecules in the bottle, there are also more molecules able to condense. This is why you can see the alcohol cloud more clearly than the water cloud.
Clouds on Earth form when warm air rises and its pressure is reduced. The air expands and cools, and clouds form as the temperature drops below the dew point. Invisible particles in the air in the form of pollution, smoke, dust or even tiny particles of dirt help form a nucleus on which the water molecules can attach.

We also checked out the "Mentos and Coke" experiment which is not connected to what we are exploring in Science right now but was awesome! We discussed what this experiment might be about before we watched it and we thought the mint in the Mentos would mix with the carbonation in the Coke to create a reaction. Peyton told us what a geyser was, "like a volcano but with water coming out of the ground." This really helped us imagine what the reaction might be. Here it is:

Our reflections:
When the Mentos went in the coke bottle the mentos were fizzy so they shot up. -Mason

When it shot out the bottle it almost used all the pop! -Brooke

It amazes me how Mentos makes the coke squirt out like a geyser. It is because the coke is carbonated and the Mentos coating is chalky. -Ricky

The Diet Coke worked better because it went higher when it mixed with the Mentos. -Michelle

How does it work? Explanation from Steve Spangler Science:
Water molecules strongly attract each other, linking together to form a tight mesh around each bubble of carbon dioxide gas in the soda. In order to form a new bubble, or even to expand a bubble that has already formed, water molecules must push away from each other. It takes extra energy to break this "surface tension."In other words, water "resists" the expansion of bubbles in the soda.

When you drop the Mentos into the soda, the gelatin and gum arabic from the dissolving candy break the surface tension. This disrupts the water mesh, so that it takes less work to expand and form new bubbles. Each Mentos candy has thousands of tiny pits all over the surface. These tiny pits are called nucleation sites - perfect places for carbon dioxide bubbles to form. As soon as the Mentos hit the soda, bubbles form all over the surface of the candy.
Couple this with the fact that the Mentos candies are heavy and sink to the bottom of the bottle and you've got a double-whammy. When all this gas is released, it literally pushes all of the liquid up and out of the bottle in an incredible soda blast. You can see a similar effect when potatoes or pasta are lowered into a pot of boiling water. The water will sometimes boil over because organic materials that leach out of the cooking potatoes or pasta disrupt the tight mesh of water molecules at the surface of the water, making it easier for bubbles and foam to form.

1 comment:

Anonymous said...

We like the videos. Science experiments are always cool to do, especially ones that have materials easy to find at home.

Jess liked the Mentos and pop one the best.
Which one did you like best?

Thanks for posting!
Heather (Jess's mom)