Some months a go I filmed a slinky falling in slow motion. Now I have interviewed the public about what they expect to happen for ABC TV’s Catalyst program and this is the result.

http://www.abc.net.au/catalyst/team/default.htm
I have been working with Catalyst on ABC1 to bring some Veritasium to Australian TV. In this segment I ask why astronauts in the space station are weightless. The most common answer is because there is no gravity in space. But of course there is gravity in space, especially where the space station is located (only about 400km from Earth’s surface). So astronauts still experience a gravitational pull – it’s just that they and the space station are in free fall so they are accelerating together towards the Earth. The space station doesn’t crash into the Earth because of its orbital velocity – it’s going 28,000 km/h so as it falls, the Earth curves away from it.

The sun has been producing light for about five billion years but where does all its energy come from? The most common idea is that the sun is burning gas – like a giant fireball in the sky. If this were true, the sun would have gone out long ago. So how is the sun actually fuelling itself? It is converting its own mass into energy. By combining protons (the nucleus of hydrogen) into helium, it squeezes some mass into energy – 4.3 billion kg per second. It is Einstein’s famous E=mc^2 which gives us the quantitative relationship between mass and energy, where c is the speed of light.

Complete unedited interviews: http://www.youtube.com/watch?v=8dcw98B2Nzg
Trees can weigh hundreds or even thousands of tons, but where do they get this mass from? A few common answers are: the soil, water, and sunlight. But the truth is the vast majority of a dry tree’s mass comes from the air – it originated as carbon dioxide

Right: https://www.youtube.com/watch?v=AS9OXzSRBMQ
Left: http://www.youtube.com/watch?v=FWQ-HJ4oGKQ
It Depends: https://www.youtube.com/watch?v=R3GHiMOHEy8
What happens when nylon rope is wound around a spool and pulled horizontally to the right? Will the spool go to the right, to the left, or does it depend on how the rope is pulled?

Are you heaviest at night before you go to bed and lightest in the morning? I tried to tease out the factors to figure out what really causes weight gain and loss during the day, and what causes daily weight fluctuations.

What is the longest drinking straw that you can actually drink out of? Well in this video, we put the theory to the test. We started off with a one metre long straw made out of drinking straws taped together. We moved on to two pieces of plastic tubing, each 6 metres in length with different diameters. Then we tried a 10.5 metre tube over a cliff’s edge. The maximum we achieved was about 7 metres though theoretically up to 10.3 metres is possible if a perfect vacuum is created.

I saw my first wild koalas while driving on the great ocean road. Generally their days are not very exciting. They spend most of their time sleeping and the rest of the time eating eucalyptus leaves. The eucalyptus leaves are tough to digest which explains their consumate napping. Plus they require bacteria in their gut to help them break down their food. This bacteria must be passed down from mother to child through the mother’s poo. It’s a tough start to life for koalas!

How long is the coastline of Australia? One estimate is that it’s about 12,500 km long. However the CIA world factbook puts the figure at more than double this, at over 25,700 km. How can there exist such different estimates for the same length of coastline? Well this is called the coastline paradox. Your estimate of how long the coastline is depends on the length of your measuring stick – the shorter the measuring stick the more detail you can capture and therefore the longer the coastline will be.

My entry to the techNyou Science Ambassadors competition, visit http://www.facebook.com/talkingtechnology and http://www.youtube.com/technyouvids to find out more about these guys.