Teachers information 

The project is designed to develop the students' abilities in the following areas.

A) Observing: Looking at the mechanical world around you and using what you see in a design.
B) Inventiveness: How can problems be solved by creative thought and development?
C) Analysis: Does the item created solve the problem effectively; if not how can it be modified and    improved?

 This is the first major problem the students will face in terms of designing and building project. In the Hold Up, the students have only to look at the world around them to come up with solutions to the problem.

In this project all that will be presented to the students is a brick. How they solve the problem effectively is really via their own creations. I have seen many incredible designs, and inventions come out of this project.

As an aside, this project was once tried with a group of Physics 12 students. They were not able to come near to the creative output or success of the Technology 9/10 students. This difference was, I believe, because the younger students were not yet locked into a regimented thinking pattern like the senior students.

Some of the basic background information that students need to understand prior to and during construction of their project are concepts of friction (bearings), ratios (pulley and gears), leverage (catapults) etc. These are generally covered well enough in most technology or power mechanics text book for the students to understand.

Simple use of hand and power tools will have to be taught to ensure that students are not hurt, or equipment damaged by lack of training. Basic soldering skills are a must do. Most of the students will use brass tubing and copper coated welding rod (which must be soldered) for parts of their design. During the design phase monitor the student's projects to help them avoid over-building of the components. Students often have the concept that bigger is better, which in the design of these projects is not always true. A well designed project can be light, strong and efficient. The knowledge gained in the HOLD UP about design strength verses weight can be transferred to this project and utilised in the development of a strong, light vehicle that will be fast,easy to steer and effective in its ability to stop.

Student Lab

Name: ___________________
Partner: __________________  

 A two kilogram brick will be used to propel a vehicle forward for ten (10) meters in a straight line. The vehicle will not only travel the ten meters, but must come to a dead stop exactly at the ten meter mark by an on-board braking system.

*If the brick stays at the start line the time to cover the ten meters is Eight (8) seconds. (gr.11 &12 the time is five seconds)

*If the brick travels with the vehicle the time to cover the ten meters is Twelve (12) seconds. (gr.11 &12 the time is eight seconds)

Marking

 The winner will be the team whose vehicle has the highest point total in the following areas: Four runs worth five (5) marks each in each area.

Speed: .........20 points. On time equals 5 points. Lose one point for every second slower, gain one point every sec. faster.

Stopping: .....20 points. Stop on 10 cm green zone equals 5 points. Lose 25% in yellow zone, 50% in pink zone,75% in black zone, 100% out of colour area.

Accuracy: ....20 points. Stop within meter wide stop zone equals full marks, lose 25% for each wheel outside stop zone.

Reliability:.. 20 points. Can it run all four heats without failure? 5 points for each completed heat.

Design: .......20 points. Does it do the job with the most efficient use of design and materials, is it original, does it look nice? This will be the teacher's evaluation mark of your project.

Teachers evaluation of Student performance:............ 100 points.

 The total mark for this project is out of 200; 80% should be considered as a passing mark. It is possible that you may be weak in one area such as braking, but perfect in another area such as speed.

DESIGN GUIDELINES

A) The vehicle may be of any design you develop. The vehicle must be constructed by your team; a ready   made toy etc. will not be allowed.

B) The vehicle must have an on-board braking system that will stop it at the ten meter mark. There are many different methods to use, but to be an acceptable brake system it must be adjustable. Rolling friction alone will not be permitted as a braking system. The greater the weight of your vehicle the greater will be the force the brakes have to work against and the longer the stopping distance. On the  other hand the lighter the vehicle the less braking friction there will  be and often the vehicle will skid for a distance before it stops

C) The vehicle cannot be connected by any means to the starting line, or finishing line after it has moved forward one meter from the start.

D) The brick may travel with the vehicle or stay at the starting line.

E) The energy supply is the brick, which may be moved through a maximum distance of one meter in any direction, any angle or combination to start the vehicle moving. If the brick travels with the vehicle the ten meters or part thereof, that forward distance is not counted a part of the above maximum.

F) The brick may transfer its energy to another source to move the vehicle, i.e. a spring, rubber band, etc.

G) Once the vehicle leaves the start there can be no remote controlling of the vehicle, it must travel on its own.

H) Multi drives, variable ratios, pulleys, gears, belts, springs, string, rubber bands, etc. can be used in the design.

I) Rolling friction will be one of the greater problems to overcome, a well lubricated bearing system for the axle units is a must. Thought should be given to the problem of making the vehicle travel in a straight line for ten meters and to a method of adjusting the steering of the vehicle should also be part of the design.

J) The method of launching the vehicle is up to the designers. The brick has only a given amount of energy available for use, but the energy output may be manipulated in a variety of methods. Some methods of launching the vehicle are catapult, pendulum, falling derrick, energy transfer and multi drive. Past experimentation has shown that the greater and faster the initial release of energy from the brick the greater will be the acceleration of the vehicle. But at the other end of the track a greater braking effect will have to be used to stop the vehicle, and a greater distance allowed for stopping.

K) It should also be noted that the vehicle itself cannot be started on a ramp or any like methods. The vehicle must start at the beginning of the ten meter mark and not before or above it. The brick on the other hand is free to move from behind, above, to the side or in front of the vehicle. The vehicle must be started by the energy of the brick and not by gravity working on the vehicle itself.

L) The vehicle may start from either end of the track.

 

The track is one meter wide, with a 60 cm. (start/stop zone) at each end.

10 cm green area in centre is the stop zone full marks
10 cm yellow area, stop here lose 25%
10 cm pink area, stop here lose 50%
5 cm black area, stop here lose 75%
Stop past the black area lose 100%

Some hints on design of the vehicles:

Bearings: At a hobby shop there can be purchased small brass tubing of various internal diameters. The � Id. tube makes great bearing material for axles.

Brakes: Several kinds have been developed by students in the past. They include a threaded axle with a nut that is free to move along the axle while at the same time being attached to the chassis of the vehicle. When the nut reaches the end of the axle, it jams into the bearing body and tries to turn with the axle, but because it is also attached to the chassis it can not and the vehicle stops. Another system has spools fixed to two axles with a string that unwinds from one spool, and winds onto the other spool as the vehicle moves. When the string runs out on the one spool that axle stops, which in turn causes the other axle to stop. Rebound is often a problem with this brake because of instant stored string braking load.

Plus Minus

A) Wood: Easy to work with Cost, can be heavy.
B) Aluminium: Light weight Cost.
C) Welding Rod: Easy to bend to shape Must be soldered.
D) Plastic: Easy to find, cheap. Very few.
E) Cardboard: Cheap, easy to work Not always strong.