Materials:

• Clean white socks
• Gloves or oven mitts
• Rubber bands
• Black markers
• Car(s)

 Activity Description

This activity can be done with one or more vehicles. If you have access to more than one car, you can compare your results!

• Label a piece of paper (or even the white sock itself)  with the make, model, and year of each car using a black marker.  
• Place the white socks over the tailpipes of each car, using rubber bands to help hold them securely if needed. Use oven mitts when securing the socks onto the tailpipes. DO NOT turn on the vehicle until the sock is secure. USE CAUTION as the tailpipes may be warm if they have been recently driven.
• Once all the socks are on the tailpipes and you have moved a safe distance away from the vehicles, start the cars and run them for 1 minute each. For more dramatic colouring of the socks, leave running for 2-3 minutes. 
• Shut the vehicles down, let them cool for 5 minutes, then remove the socks from each vehicle using oven mitts or gloves. Examine the socks and determine which is the dirtiest, the cleanest, and the most and least wet.

Safety Precautions 

• This experiment should never be done in a closed building such as a garage- ensure you are in a well ventilated area and that you stand away from automobiles during the test as exhaust tailpipes emit carbon monoxide gas and can cause burns.
• It is recommended that an emergency brake should be set on each vehicle to keep the vehicle from rolling. 
• Always use oven mitts or gloves when putting socks on and taking them off- tongs may also be used for added safety. Do not touch the tailpipe until car has cooled for five minutes.