Projects.org.nz

Keen to do a science and technology fair project but don't know where to start. Check out a website a group of students and teachers (including I) put together in 2012 to give students resources to do science and technology fair projects and teachers the resources to integrate science and technology fair projects with NCEA. I have just added a Facebook page and added in a new forum to the wiki. Also if you a teacher or student and want to contribute that would be great.

www.projects.org.nz

There are five main sections of the website including

Steps - What are the steps to complete a science or technology project? What are some tips and tricks to making award winning projects.
Pathways - A teachers resource for NCEA integration with science and technology projects.
Forum - Need help with your science and technology fair project or need help with ideas check out the forum.
Other projects - Get inspired with other students projects and where they have taken them.
Mentoring - Want to get connected with groups and researchers that can help you with your topic. Fill in the form and we can get back to you with people that can help.

Projects.org.nz

Lunar Eclipse

This Saturday stayed up with some leaders from Easter camp out at Bucklands beach to watch the lunar eclipse. Thanks to Jack Fowler we captured the whole event on his iphone pushed up against the eyepiece of my small 76 mm Newtonian telescope with a moon filter. Here are the shots.

Thanks also to the group that stayed up till 1pm with me to capture the eclipse that started at around 11pm.

Scientists have only just worked out how sodium explodes in water

This classic experiment is one of the many explosions that encouraged me to pursue a career in chemistry. But ever wonder why it explodes I thought that the generation of hydrogen on the surface had a part to play this does explain the burning but for an explosion you need to have a large enough surface area to have a reaction fast enough to really get a boom. If you know anything about the thermite reaction or flour bombs a huge surface area allows the reaction to proceed fast enough to build up pressure and explode. Also unlike gun powder which already has the fuel and oxidant mixed together only at the sodium water interface can you get the reaction so surface area is crucial. Using a high speed camera and some neat simulations researchers have just work out how sodium increases it's surface area enough to cause an explosion.

Put most simply sodium quite easily gives up its outer most electron and becomes the positive sodium ion. What they found was that when sodium is put into water the water sucks the electrons from the surface of the sodium metal. Without the electron you just have positive ions which repel each other this causes small needle like fingers of sodium to extend into the water. This greatly increases the surface area causing hydrogen gas build up and allows for the big explosion.

The high speed images show the needle like filaments. The crucial frame is 0.4ps 5th image from the top middle column where you can see the needles of sodium and potassium (potassium is added to make a liquid metal for easier dropping). The next frame shows the explosion at the surface.

Now comes the awesome simulations. So using quantum calculations they modeled nano drops and show the electrons (blue in the image below) moving into the water and then the sodium ions breaking apart as there are no longer any electron glue to hold them together.

  

Scaling up the simulations using some assumptions that reduce the amount of computer processing time they showed a larger drop exploding at the surface.

 

Check out the movie they put together and the paper. I wonder what other elementary reactions are still not fully understood.

 Mason, P. E.; Uhlig, F.; Vaněk, V.; Buttersack, T.; Bauerecker, S.; Jungwirth, P. Nat Chem 2015, advance online publication.