Botany Downs College	Expert feedback from John Cocks, waste engineer
1. Laura, Jessica, Chandana, Aretha and Avishka's PowerPoint.	1. Effectiveness: It is great the way you have explained your trial and error methods of trying to control the water. You have demonstrated well the effectiveness of building a model and testing it and finding out what works and doesn't work. We are interested to know how you joined the 2 bottles together so that they did not leak? Also have you thought about catching the used water water for irrigation? When you take the cork out do you lose more water than you need to wash your hands? Durability: From what we understand you have built a practical and durable prototype. User-friendliness: Very. Communication: An extremely good job done explaining your progress in the building the system. A great presentation.
2. Click here for a PDF of Lewis, Micheal, Angus and Ashleigh B's device, detailed instructions and photo.	Effectiveness: It is good that you first designed the model and then actually made the prototype. That is the best way to find out whether something works. I am not sure how much water you would lose between pouring the water into the bottle and cupping your hands ready to wash. Durability: The plastic bottles and wooden stake are durable but tape won't last long outside.The fabric will also disintegrate within a short time. User-friendliness: Very user-friendly.You can easily see how it works. Communication: Good instructions based on practical experience.
3. David, Daniel and Tzu Jui's PDF of their device, hand washing instructions and diagram.	2. Effectiveness: The concept illustrates an effective machine.That was clever! You can control how much water is used and manage it carefully. Sand is a good filter for coarser materials but it is not so good for keeping out bugs unless it is about 1 metre deep. It is good to see your model. We would have like to see some close ups to see some more detail like the foot pedal. Durability: With the right materials and connections it would be durable. User-friendliness: A good very user-friendly design. Communication: A good job in describing the concept though diagrams and words and through a photo of the model.
4. Christina, Jenny and Aarushee’s song (and sound file), hand santiser experiment and song recording. Our completely natural hand sanitizer: Ingredients: 1 cup Aloe Vera gel 4 tablespoons of spirits (ethanol) ½ cup of lemon juice 3 tablespoons of tea tree oil Method Slice the skin of the Aloe Vera stalk and scoop out the white contents (this is the gel) Mix together the ingredients up until they form a smooth mixture.	4. Feedback from Elaine Burgess - plant scientist: Well thought out to use aloe vera as it is a natural healing gel and reported to be antibacterial and fungal. Alcohol and lemon are antiseptic so would work well as a mixing agent. Using the lemon peel as well would enhance this. Tea tree oil is reported to be effective against all three categories of infection bacterial, fungal and viral and would therefore promote this sanitizer's effectiveness. I would suggest to use it in a more diluted form as the acid in lemon juice can cause skin irritations. Re the experiment - for it to work the agar and petri dishes would have to be sterile. Also once opened to put the fingers on etc aerial bacteri would get into the dish as well. Therefore it won't tell you if the sanitizer is working unless every thing is done in a sterile environment. The experimental design is good though! It is true that cell walls are disrupted at low pH but it would have to be very strong so again lemon juice would need to be diluted in cases of sensitivity. The song is marvellous. Just long enough for a good hand clean while appealing to school children with the 'keep you clean and cool.'
5. Han-Seo, Nicholas, Mitchell and Kieran's PowerPoint .	5. Effectiveness: This is a basic and robust looking concept. You would have to wash one had at a time or there would be a high loss of water if washing both hands at once. You should make sure you don't touch the end to make sure it doesn't get contaminated. Constructing the prototype proves the concept works. Well done! Durability: Strong and durable materials. However the connection between the pipe and the tin may leak a little? User-friendliness: Extremely. You can see how it works immediately. Communication:Well presented diagrams and photographs. Overall a marvellous project.
6. Ashleigh T, Alina and John's PDF of their device.	6. Effectiveness: The sieve will filter out larger debris. You have a large robust container for water storage. I do not fully understand outlet control ie allowing a small amount of water for washing hands but avoiding waste water. By the time you have opened it with the string there will be water loss and the same with closing it. Durability: Very durable design although outlet control needs to be better understood to make comment. User-friendliness: Yes it appears to be very user-friendly. Communication: Good photographs and the use of pidgin is excellent and well placed. Well done!
7. Abby, Amy and Braden's PDF of their Instructions For Hand Washing Device. **************************************** Collect your certificates from here.	7. Effectiveness: A good looking concept with storage, filtering and outlet control. It will need the building of a prototype to demonstrate how to build it so that it works well. Durability: This will depend on the material used for the different parts and the connections to join these different parts together. User-friendliness: Yes. It looks very user-friendly. Communication: The concept is well communicated but more information is needed to actually build it.