Grade 6 Science- Properties of Fluids

As an introduction to our unit on flight, one of the most important concepts is understanding the properties of fluids. Today, we learned that air is an example of a fluid because it flows and takes on the shape of its container.

We can completed an experiment to demonstrate how the adding of heat to a substance expands the particles that make up our air and how removing heat brings air/particles closer together.

We first placed a balloon over the top of an empty Erlenmeyer flask. The balloon appeared to be mostly deflated, but I had blown some air into the balloon prior to placing it over the opening of the flask.

I placed the flask into a beaker full of hot water and the balloon grew and appeared to inflate. When placed back into cold water, the balloon appeared to deflate once again.

Students had to explain why they thought the balloon expanded (grew) and contracted (shrunk) when hot water and cold water were added to it.

1st photo- Flask with balloon attached and 2 beakers. The beaker on the left is filled with  hot water. The beaker on the right is filled with ice water.

2nd photo- After just 5 seconds in 60 degree water, the balloon has risen and appears to have inflated.

3rd photo- After placing the balloon into 6 degree water, it took just a couple of seconds for the balloon to deflate. As more time went on and the flask cooled down, the balloon appeared more deflated than at the start of our experiment.

So what happened. The balloon was never taken off the flask so no air escaped? How is it possible for the balloon to expand and contract based on temperature?

To learn more and to understand how this happened, please visit the "Classroom" page on your Google Drive to view the Powerpoint.