Demo Description:
This demonstration uses a balloon with marks on it to show how the expanding universe causes celestial objects to move further apart.
Equipment:
- Balloon
- Sharpie
- Hose with attached rubber stopper
- Ruler or meter stick
- Room or document camera, depending on size of the lecture room
Location: H132-B4
Caution / Safety Info
Please see the Safety Information page (link) regarding the following risks associated with this demonstration:
- general safety practices
Setup Procedure:
- Make sure the balloon is prepared: draw at least two sharpie dots on the balloon, ideally more.
- Insert the rubber stopper end of the hose into the mouth of the balloon, making sure it’s secure and won’t pop out when the balloon inflates.
- In the classroom, attach the other end of the hose to the air spigot on the desk (NOT the gas one!)
Demonstration Procedure:
- Show the class the two markings, using either a room camera or document camera as needed. Use a ruler to show how far apart they are.
- Open up the air valve and begin to inflate the balloon. Point out the markings as it begins to stretch.
- Show the class that the two markings are now further apart using the ruler.
- Steps 2 and 3 can be repeated to show that the markings get further and further apart as the balloon expands larger and larger.
Notes
- This pairs well with other demonstrations on universe expansion.
