How the Rubber Meets the Road

Student Worksheet: 
Design Your Own Tire Tread Pattern

You are a team of engineers who have been given the challenge to develop a unique tire tread pattern out of clay that will route over 50% of incoming water to the sides of the tire to prevent hydroplaning.  As a team, you'll need to preserve at least 60% of the surface of the "tread" so that the tire will be able to grip the road firmly. 
Step 1: Meet as a team and discuss the problem you need to solve.  Then develop and agree on a pattern you will use for your tread.  You may each want to come up with a simple idea, and then select the best aspects of each design to develop a group pattern. Draw the pattern in the box below, and be sure to indicate not only the shape of the grooves, but also how deep your grooves will be carved into the "tire."

	
How the Rubber Meets the Road

Student Worksheet (continued): 

Step 2: Transfer your team's design to the clay block using a pencil.  
Step 3: Carve your design plan into the clay block provided to you, using plastic utensils or kid-safe clay tools. 
Step 4: Use the table below to predict how your tread will perform in the water test.
	Predicted average results	
Amount of water in middle/bottom container
	%:	
Amount of water in left container

	%:	
Amount of water in right container

	%:	

Step 5: As a group, present your engineering teams' plan to the class.  Explain why you chose the patter you did, and explain what you think will happen when you test your design.  Be specific and anticipate the percentage of water that will end up flowing to the left and right containers instead of flowing straight through to the bottom container.  Also explain how you decided on the depth of the grooves and whether they are a consistent depth throughout the design. 
Step 6:  Testing time! Your teacher will have set up a testing station for the treads.  Your teacher will decide if you will test your own treads, or if a team of "testers" will be appointed to do the work.  The testers will pour water through the top of the tire and then you'll measure and record how much water ended up being pushed to the left or right container as opposed to being gathered in the bottom container.  Your tire "tread" will be held using tape at about a 25 degree angle, so the flow of water will be consistent from team to team.  Measure the water collected at the bottom container, as well as the water collected from the right and left side to determine the percentage that was pushed away to the side.  

How the Rubber Meets the Road

Student Worksheet (continued): 

Step 7:  Mark your results in the box below. You may try your test up to three if you didn't get the results you wanted on the first try -- but you'll have to average your results.  Include both the actual amounts of water gathered and the percentage of all water for each container.

	Test 1	Test 2	Test 3	Average of completed tests	
Amount of water in middle/bottom container
	Amt:
%:	Amt:
%:	Amt:
%:	%:	
Amount of water in left container

	Amt:
%:	Amt:
%:	Amt:
%:	%:	
Amount of water in right container

	Amt:
%:	Amt:
%:	Amt:
%:	%:	
Total water gathered

	Amt:	Amt:	Amt:		

Step 8:  Complete the following evaluation/reflection questions and present your findings to the class.
1. Did you succeed in creating a "tread" that could route over 50% of incoming water to the sides of the tire to prevent hydroplaning?  

2. If you did not reach the goal, what would your team have done differently?

3. How did your predictions for your tread performance vary from your actual results?  

How the Rubber Meets the Road

Student Worksheet (continued): 

4. Did you test your "tread" more than once?  If so, how do you think that 
averaging your test scores impacted your overall results?  

5. What was the most significant design different of your "tread" as compared to those of the other student teams?

7.  Describe a feature of another teams' "tread" that you thought was particularly inventive.  Why?

8.  What impact do you think the depth of the pattern have on your teams' outcome.

9.  Do you think you would have been able to complete this project easier if you were working alone?  Explain…

10.  How do you think engineers test tire tread designs in the real world?  Consider computers, test driving tracks, and other options.  And, also discuss how making a prototype might, or might not, be useful.