Everyone knows the alka seltzer rocket experiment, but not everyone has seen a ghost fly! Scare up your lesson plans with an easy example of a chemical reaction.
This Halloween activity is so easy, and nothing is more fun than watching your students’ faces when the first ghastly ghost takes off into the air.
It’s a great opportunity to demonstrate what a chemical reaction is: when one substance changes into another substance.
The concepts of energy, thrust and gravity are also present. I presented this at the lesson wrap-up when we talked about why some ghost rockets could fly so high and what made them come back down to earth.
host Rockets – The Lesson
This was actually part of a 3 station event my co-worker and I did:
- Ghost Rockets
- Boo Bombs
- Pumpkin Estimation
We planned an entire morning dedicated to Halloween science and math lessons, along with some diagramming and labeling.
The kids’ favorite activity was definitely the Ghost Rockets. To prepare, you need to order white film canisters (just Google it) and draw a ghost face on each one. For the actual lesson, you will need 1/2 an Alka Seltzer tablet for every student and a jug of warm water.
Beginning
Ask the students what they think will happen when you put an Alka Seltzer tablet into the container filled about half way with water (be sure to emphasize that it is Alka Seltzer, not alcohol as some of my younger students thought!).
Put in the tablet, quickly snap the lid on, turn it over so the lid is on the ground, and step back to watch!
Middle
Gather them around you and talk about what happened and why. This is a great time to introduce the concepts of air/gas taking up space, along with the chemical reaction that took place in the canister.
- When the water and Alka Seltzer combine, bubbles of carbon dioxide are released.
- The lid has to be on tightly so the gas is contained.
- The more gas that is created, the greater the pressure inside the container.
- Finally, enough pressure is built up the overcome the lid seal. The pressure exerts enough force to shoot the ghost rocket into the air!
End
Now it is time for the students to recreate the demonstration. Plan for them to do it at least twice because someone is definitely going to dump their rocket, not put the lid on tightly, etc.
Later, if you have time, turn this into a real experiment. Ask the students how they can make their rocket fly higher:
- hot water?
- cold water?
- a whole tablet?
- more water in the canister?