This post is written by Owl.

On Friday 15th March we (mummy, Monkey, Rabbit and I ) went to the Big Bang Science Fair at the Excel Centre in London.  We went on four trains to get there, and waited for our Home Education Group friends to arrive.  Then we went and watched a Strange Science show with lots of good experiments.  These are a few of them:

1. The man presenting the show placed a glass funnel in a large jug of oil, and put his finger in the narrow end of the funnel to keep the air inside.  We could see the funnel clearly.  Then he took his finger out and the funnel became invisible.  It was still there but we couldn’t see it because there was no air trapped inside and it filled up with oil.  The reason we couldn’t see it was that oil and glass have the same refractive index, while air is different, so the path of the light going through the oil does not change when it hits the glass, but it changes when it reaches the trapped air.  The man demonstrated this by shining a laser on it, to show how the path of the light bends when there is air in the funnel, but it is straight when there is no air.
2. The man passed a low level of electricity through three volunteers from the audience.  It didn’t hurt them but was enough to play some music.  One person on the end of the line held a wire connected to a laptop which was playing music, another stood in the middle of the line, and the one at the other end held a wire connected to a speaker.  When their fingers were touching the music played, and when they separated it stopped.
3. Finally the man touched two plasma balls at once with one hand and held a fluorescent tube light with the other.  The electricity passed through his body and the bulb lit up.  He said it hurt a bit so he didn’t ask for volunteers this time.

After the show, we had lunch and met up with some of our friends.  Then we explored the exhibition, which had so many stands but we could only look at a few.  These were some of the best ones:

1. There was a stand about drugs, and I helped to do an experiment about caffeine.  I had to use a dropper to pick some daphnia out of a jar of water and place them on a slide under a video microscope.  We could see a heart beating on the screen and I had to count the number of heartbeats in 15 seconds and then multiply by 4 to calculate the number of beats per minute.  We then added some caffeine and counted again, and the heart rate was higher.
2. On another stand there was a presentation about what happens when someone is in a car accident.  There was a dummy the size of a man, and some air was pumped into his chest to make it look like he was breathing.  There was lots of fake blood.  Some volunteers put bandages on him, and we discussed ways of making him comfortable.  I helped to put a mask on his face so he could have gas and air.  They said he would have to go the hospital for further treatment.
3. Then I talked to a man about the landscape of Mars and he showed me some pictures of features of Mars to compare with similar features on Earth.  There were craters, volcanoes, plains and river beds that would once have been filled with water.

After that the little ones were tired so we went home.  I hope we can go again next year.