HALLOWEEN SCIENCE: Boo Bubbles, Ghost Poppers & an exploding pumpkin
Halloween is right around the corner and WITN's resident 'scientist', Ms. Covey Denton has two family-friendly experiments to try at home -- and one that's just to watch and enjoy!
If you've blown bubbles indoors, maybe you noticed the occasional bubble that fell on the carpet but didn't pop. Bubbles burst when the come in contact with oil and dirt. Soap bubbles will bounce off a surface if its fee of oil or dirt particles which is why we can get them to bounce off the soft gloves.
Instead of air to fill the bubbles, we're using dry ice. Dry Ice is frozen carbon dioxide (CO2) and when it warms up, it turns directly from a solid to a gas instead of melting. When you drop a piece of dry ice in a container of water, the gas that you see is a combination of carbon dioxide and water vapor. So, the gas is actually a cloud of tiny water droplets.
Grocery stores use dry ice to keep food cold during shipping. Some grocery stores and ice cream shops will sell dry ice to the public (especially around Halloween) for approximately $2 per pound. Make sure you store your dry ice in a cooler and not your freezer! As it warms up it will turn directly into a gas and can blast open your freezer door--talk about spooky!
The fizzing you see when you drop an Alka Seltzer tablet in water is the same sort of fizzing that you see when you mix baking soda and vinegar. The ingredients of alka seltzer have cirtic acid and baking soda (sodium bicarbonate). When you drop the tablet in water, the acid and the baking soda react to produce bubbles of carbon dioxide gas.
The film canister isn't stretchy so the pressure builds up. When the buildup of carbon dioxide gas is too great and the lid pops off, Newton’s Third Law explains why the film canister flies across the room: for every action there is an equal and opposite reaction. The lid goes one way and the film canister shoots out of the tube in the opposite direction.
You can try the experiment with different temperatures of water. Warmer water speeds up the reaction, colder water gives a delayed effect.
The chemical reaction that takes place inside the pumpkin generates a very small amount of acetylene gas. When the gas is ignited, a tremendous amount of energy is released in an explosion. This explosion pushes the pieces of previously carved pumpkin out. Acetylene gas is very explosive. Only a chemistry teacher should do this experiment! Definitely not one for home!
It took two tries for us to explode the pumpkin on News at Sunrise, so be sure to watch both videos. The first has the explanation and the second shows the explosion.
Denton is an award-winning science teacher at The Greenfield School in Wilson, NC. Denton and her three children, Elijah, Bethany and Lydia make regular appearances on WITN's News at Sunrise.
Look for details on our big Halloween show ... spooky soon.