# Month: January 2021

## Carbon Dioxide Candle Experiment

Contributed by David Jiang Introduction We’ve all seen fire extinguishers before and its powerful stream of nitrogen which can smother a dangerous fire. However, imagine a fire extinguisher that can take out fires “invisibly”. Here is a fun experiment to design your very own, invisible fire extinguisher. Materials 2 regular-sized cups Matches/Lighter 1 candle Vinegar…

## Bouncing the Ball

Contributed by Jikai Xu Introduction When you drop a ball from the air to the ground, you may naturally suppose the ball will bounce back to a lower height than the releasing position. But, can you imagine a ball to bounce back to an even higher position? Materials A small ball that can bounce back…

## Balloons and Static Electricity

Contributed by Sabrina Brickner Introduction How does charge work? Can we really see how electrons work without fancy science tools? Materials Balloons Someone with hair on their head A working faucet An empty metal can Procedure Blow up a balloon. Rub it on your head. Watch what happens to the balloon and your hair. Turn…

## Magnetism

Join Jared as he introduces Magnetism, and explains why it’s closely related to electricity! Whereas electrons are simply negative charges, magnets have two poles; a North and South end. The Earth is actually a giant magnet, and the magnetic poles are where the north and the south pole are, so we call the magnets’ ends…

## Electricity

Electricity comes from moving electrons, or negative electric charges. Join Jared as he introduces the van de Graaf generator! When the machine is turned on, the belt will move and rub against a piece of carpet at the bottom, picking up electrons. It brings the electrons up to the metal dome. Since electrons are negatively…

## Sound

What is sound? Here is Molly Kaplan, gravity theorist and musician extraordinaire, introducing sound waves: Using a Slinky, Molly demonstrates that waves can move in two different ways; up and down or back and forth. Waves that move up and down, such as waves in the ocean, are known as transverse waves. By contrast, waves…

## Air Pressure

The air we breathe is actually a gas made up of tiny particles constantly flying around and bumping into one another! Here is Jared Goldberg, who studies the physics of stars, discussing air in static and dynamic situations. Did you know that the air is always pushing on you? We call this air pressure. It…

## Liquid Nitrogen

In this demo, Jared explores the properties of Liquid Nitrogen, which is air cooled to −196°C (−320°F). Air is composed of 78% Nitrogen and 21% Oxygen, and is usually a gas. When air is cooled to −196°C, the Nitrogen in air condenses, or becomes liquid. This is an example of a phase transition, where a…