woodchurch science

by ellen williams 8yw :on thursday 30th march, a lecturer from liverpool university named ‘sian owen’ visited our school to present a lecture to year 8 science sets called ‘science is cool’. all of the science groups in year 8 came to watch the fascinating experiments that were performed.

The main substance used in all of the experiments was called liquid nitrogen
which is nitrogen cooled down to -196°. It was that cold that when it was
poured onto the stage, it turned into gas and evapourated before it even
touched the floor, it was actually boiling at -196°!

The first experiment that Sian showed us was with liquid nitrogen and some
balloons, she walked around the hall picking the balloons out of a bucket of
nitrogen and dropping them onto the floor. About two seconds later, the
balloons started to self-inflate until they were at the normal size of
balloons. A couple of them even popped because they grew so big!

Sian explained to us how the liquid nitrogen actually worked, she bought out
a bag full of plastic balls and told us that when an object is in the bucket
of nitrogen the particles react differently from when they are outside and
have heated up to room temperature. She explained solids by slightly shaking
the bag of balls and they just vibrated a little but stayed in the same
place. Then she explained about liquids, when she shook the bag a little
harder, the balls vibrated a little more, they were actually moving around
but not leaving the bag. Then Sian explained gas, it was quite funny, she
threw the balls all around the room and when somebody caught one, they had
to throw it to someone else, they were flying all over the place.

The audience was then treated to what was beginning to feel like a magic
show. Sian showed us an elastic, rubber tube. She demonstrated how flexible
and stretchy it was to start with, then it was placed in the liquid nitrogen
for a couple of seconds. On removing it from the liquid nitrogen, she hit
the rubber tube with a small hammer and it shattered all over the floor like
glass. Sian then walked around the hall smashing the tube on the floor and
she handed out the pieces. When we felt the pieces, they had turned back to
rubber, very flexible and stretchy. This was due to the temperature of the
room.

Sian then said that she wondered what would happen if she put her fingers
in, but instead she put a banana in as an example, while she waited, she
explained that bananas are sort of like fingers because they contain lots of
cells like fingers. When Sian pulled out the banana, she placed it on the
stool and again hit it quite hard with a small hammer, instead of just
squishing it, like you’d imagine, the hammer smashed it and it shattered
like the previous experiments had.

The next object that Sian placed in the bucket of liquid nitrogen was
something that the audience found very funny – it was Mr Sanders tie! She
asked him to keep it on and place half of it in the bucket for about ten
seconds. Poor Mr Sanders was standing there wondering if one of his
favourite ties was about to be shattered into hundreds of little pieces.
When he pulled out his tie, Sian placed it on the stool and making sure that
Mr Sanders was out of the way, she hit it hard with the hammer. But nothing
happened – it stayed in one piece. Sian then explained to us that this was
because of the type of material that the tie was made of and the fibres in
it. Poor Mr Sanders walked off the stage with a very cold and quite wet tie
and a shocked face.

To demonstrate this again, Sian placed a small cuddly toy inside the bucket
for a couple of seconds then she thrashed it with the hammer and nothing
happened. This had proved why Mr Sanders tie didn’t shatter or smash either.

This next experiment was a little bit of a trouble maker! Sian asked anybody
in the audience if they were chewing and if she could use their chewing gum.
A couple of people gave her their gum and she put the pieces onto a little
piece of cloth. Sian poured some liquid nitrogen onto each piece and smashed
them with the hammer. The pieces of gum came off very easily when she
smashed it but it didn’t exactly go according to plan. A hole was made in
the places that the chewing gum was stuck but it was really interesting.

Suddenly, Sian picked up a small bunch of flowers and placed them in the
liquid nitrogen for a couple of seconds. When she hit these with the hammer,
they too smashed into small pieces. They were rock hard, then a few seconds
later, they turned back to their normal state, just like the rubber tube.

We were fascinated as Sian poured liquid nitrogen into a frying pan, and
then cracked an egg into it. They egg then turned very hard but took a
little longer than other materials so she put it to the side whilst she did
other experiments.

It was time for Sian to try something that she hadn’t actually tried before,
this was a bit of a dare but she asked if anybody in the audience had any
ten or five pound notes with them and somebody gave her ten pounds. Sian
placed the note into a clear jug full of liquid nitrogen and we knew it had
turned hard because we could hear it knocking onto the side of the glass
like plastic would of. Then, Sian took it out, placed it on the stool and
smashed it with the hammer! Nothing happened. She was obviously this but the
owner of the ten pound note was looking relieved. She explained that the
reason that it didn’t smash was because she had waved it around when she
took it out of the jug and it quickly turned back to its normal state
because of the temperature. To prove this Sian took a paper towel and placed
it in the jug, when she took it out, it was dripping wet and then 5 seconds
later, it dried up completely, it was like it hadn’t even been wet!

Finally, Sian went back to the egg, she held it up for everyone to see and
it was like she was holding plastic toy egg! Amazing.

This was an educational and extremely enjoyable lecture for all of us and we
had a great time. I hope you enjoyed reading about this and I would like to
say thank you to Sian Owen for teaching us that Science really is COOL!

This entry was posted on Tuesday, May 9th, 2006 at 9:51 am and is filed under chemistry, events, ks3, oldham, y8. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.