Sunday, 15 June 2014

Onehunga high school visit to the Photon Factory

Here are some notes for the students coming from Onehunga High School to take part in practical science projects. Below is a list of the different projects.

During the course of the day we are going to be drawing up some slides about the project you have chosen including:
  • Background research
  • Design of the device
  • Building the device and testing
  • The questions will you ask with what you have made
Clean drinking water using natural microorganisms
3.4 million people die every year from water-related diseases. This is largely due to pathogens living and breeding in the water. There are many different ways to clean water of microorganisms; filters and solar precipitators to name just a couple. However, there is a way to filter out microorganisms using other microorganisms. Using a biosand filter (a bucket full of sand) that slowly empties, water can be sanitised simply and naturally. A thick biofilm forms on the surface of the sand and breaks down bacteria. Then the sand allows for filtering of water and provides a dark place where the bacteria die from lack of food. How the biofilm and each different element work is still not fully understood. We will make a biosand filter and look at what experiments can be done to improve our understanding of the biosand filter.

Timelapse images for long term changes in nature
The climate is changing due to an increase in greenhouse gases in the atmosphere. This rapid change is going to have a huge impact on the environment around us, particularly on plants which are dependent on the weather cycles to survive. Due to the slow movement of plants it is hard to look at trends in their behaviour. Using special time lapse photography we can watch the long term movements of plants using a simple webcam and computer software. By stitching the images together  using software a video can be made and analysed. We will be building an enclosure for a webcam to be set up outside to collect images of plants growth. We will also look into using algorithms to exaggerate the movement of plants to observe subtle changes in the plants as they grow.
Revealing Invisible Changes In The World - YouTube

3d printed spectrometer using a CD grating and a cell phone
Have you ever wondered why something appears blue or red? What determines a material's colour? A spectrometer is a device that can measure the light that comes off an object. We are going to make one of these using a normal CD which has lots of small pits in its surface which allow it to reflect light of different colours in only one direction. This means that if white light enters in at a particular angle, the colours spread out at different angles and can be measured individually. These have been used to look at the different chemicals are in stars and on planets. They are also used to detect contaminants in water. In the Photon Factory we use this to look at how energy moves around molecules and we are working on making artificial leaves that turn sunlight into energy. You will build your own spectrometer and attach it to a cellphone to find out how you can help the world by conducting experiments with your own spectrometer.

Invisible light camera reveals when plants are stressed
We can see from blue light (~400 nanometers) to red light (~600 nanometers). Outside this range we are blind, however continuing past the red end of our vision will show signatures in plants that would otherwise be invisible. Plants absorb red and blue light but reflect green light. But what about the invisible light? Plants reflect near infrared light (NIR) (~700nm - ~1200nm) very well also. However, when they are under stress the part of the plant that reflects the NIR becomes damaged and the plant reduces its reflectance. This can happen when there is a pest invasion or when the plant is not getting the right nutrients or water. Using a simple webcam we will remove the infrared filter from the camera to see the invisible light, then add a red filter. This replaces the red channel with the infrared to show stress in the plants.

Biochar and efficient stoves for safer cooking conditions and carbon sequestration
The majority of the world still uses open fires for cooking food. This presents a health risk due to smoke inhalation and also leads to pollutants in the environment. Using a different way of burning wood, a highly efficient stove (gasifier) can be built that firstly turns the wood into a gas and then burns that gas in another part of the burner. This gasifier can then burn the fuel more efficiently with fewer harmful emissions. One of the byproducts from this process is charcoal, a solid form of carbon, that is very difficult to break down. When wood grows it uses and stores carbon dioxide, a greenhouse gas, and when it dies microbes break down the wood and the carbon dioxide is released. By heat-treating the wood carbon can be trapped in the ground for thousands of years. The application of charcoal to the soil (this type of charcoal is known as biochar) was first done with soils along the Amazon. Ancient Amazonians would put food waste and charcoal together to produce a very potent fertiliser. We will build a gasifier out of a can and a computer fan, then design some experiments to test out the effects of the charcoal on different plants and soils.

This is just the beginning. If you want to continue doing the project you were assigned or another group's, then you can enter the high school science fair.

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