You may be able to make arrangements to have a school bus available for the experiment. The experiment should never be conducted in a closed building. Emergency brake should be set on each vehicle. Use oven mitts or gloves when putting socks on and taking them off. Students should stand away from the automobiles during the test.
Exhaust pipes emit carbon monoxide gas and can cause burns.
Do not touch the tailpipe until car has cooled for five minutes. Place a white tube sock over the tailpipe of each vehicle and then start the engines. Make sure the students are standing away from vehicles before starting engines. The elastic sock tops should fit snugly over the tailpipes. If not, secure with rubber bands.