Design, Construct, and
Demonstrate a
Ball Shooter
Submitted by:Bonnie Boardman
University of Texas at Arlington
boardman@exchange.uta.edu
Ball Shooter
Team Project
Objective
Each team will design, construct, and demonstrate a device that will successfully hit a
target with a tennis ball. The target will be a flat grid of 1 foot x 1 foot boxes. The total
size of the grid will be 5 feet x 5 feet. The grid will be placed on the floor with the center
box designated as the bull’s-eye box and surrounding boxes used for scoring.
Requirements
1. Your device must have a footprint of no greater than 2 feet by 2 feet. There is no
height restriction. The entire device must stay within the 2’ x 2’ square before,
during, and after operation.
2. The front edge of the target will be placed at a location somewhere between 5 feet
and 25 feet from the front edge of 2’ x 2’ box in which your device sits and the front
edge of the bull’s-eye box. You will not know the exact distance of the target until
the day of testing. Your device will need to be adjustable and you will need to
calibrate prior to test day so that you know what adjustments to make on test day.
2’ x2’
area for
device
x feet
3. Only the portions of the device in contact with the floor before firing the tennis ball
may be in contact with the floor after the ball is fired.
4. Once the ball is released, your score will be based upon where the ball first hits the
floor. The decision of the judges is final.
5. When demonstrating your device, no trial runs will be allowed.
6. You will provide your own standard tennis ball for the demonstration.
7. No chemical reactions can be used.
8. The maximum time for project demonstration is 4 minutes.
9. A group member will start the demonstration; afterwards, the demonstration is
“hands-free.” Additional human intervention to complete the demonstration will be
penalized.
10. The maximum cost for materials used in the tennis ball shooter must be less than
$30. This includes all materials used in the shooter. A cost estimate must be
included for any items already owned by a team member. This cost estimate must
be included in the $30 team limit.
11. No live animals may be used in this project.
12. Creativity is an important part of any engineering project. There will be bonus
points awarded for the creativity and design of the project (see scoring section.)
Demonstration
1. The project demonstration will be held during your class hour. We are likely to start
a half hour early for groups who can be there. You will be notified well before the day
of the demonstration. (You may need to stay up to 30 minutes beyond the class time
to complete the voting.)
2. Your group’s project demonstration can begin only when your entire group is
present.
3. Your group will be directed to a location where you will set up your project. You will
have two minutes to set up.
4. A group member or members selected by the judge will verbally describe the
operation of the project.
5. The tennis ball to be used during demonstration will be provided by you.
6. Your device will be scored based upon two consecutive shots. The two shots as well
as any resetting of your device must all happen within the 4 minute time limit.
Scoring
1. The target will consist of a grid of 1’x1’ squares. The center square will represent
the bull’s-eye. A ball that hits outside the bull’s eye will be scored based upon the
square in which it hits. 5 points will be deducted for every square in the grid.
Rectilinear distance will be used to measure. See the examples below.
1
= 100- (4*5)=80 points
= 100-(2*5)=90 points
= 100-(2*5)=90 points
1
2. Any ball that does not hit the grid but has forward displacement will be awarded 35
points.
3. The score recorded will be where a judge determines that the tennis ball first hits
the ground after being released by your shooter. All judges’ determinations are
final.
4. Your grade will be determined as follows: (Average numerical score of both shots) +
bonus (10, 8, or 6 points for creativity and simplicity)
5. Teams will display their device for up to 30 minutes after all teams have been tested.
6. During this display one or two team members will stay with the device in order to
answer any questions from viewers about the design or operation. The remainder of
the team will view the displays of the other teams.
7. Each team will be given a slip of paper on which they will rank their top three teams
with respect to creativity and also with respect to simplicity. These will be tallied
and the top 3 teams in each category will receive 10, 8, or 6 bonus points.
8. You will not be allowed to vote for your own team in either category.