“POP!” High pitched screams exploded in the classroom as orange shards of balloon flew towards us. This was one of our favourite, intriguing experiments which we were able to observe. On the 16th of March we had a Fizzics incursion. This was a great opportunity to extend our knowledge about the properties of solids, liquids and gases. In particular, we really enjoyed learning about the properties of liquid nitrogen.
We found out many facts about nitrogen, like that 78% of the air we breathe is nitrogen. We also found out that nitrogen (N2) is colourless, odourless and a tasteless gas. Nitrogen is boiled at 196º celsius. Whilst having a great deal of fun, there were many lessons that we learned.
Our ‘science teacher’ Ben had fascinating demonstrations to share with us and taught us a lot. He poured liquid nitrogen into a cup and a cloud came out of the cup and then dropped downwards. We wondered why it dropped down and didn’t rise. We learned that the nitrogen condensed, (the molecules clumped together), got heavier and therefore dropped downwards.
Ben then put the liquid nitrogen into a tin and then put the lid on. The lid popped off with great force. We learned that when gas is heated, it expands. The gas molecules in the tin warmed up quickly causing the nitrogen gas to expand rapidly. The pressure in the tin then built up causing the lid to pop off.
One of the demonstrations which we really enjoyed was when Ben put liquid nitrogen into a bottle. He placed a lid on the bottle but the lid had 2 plastic straw ‘vents’. He then placed the bottle into a cup, half filled with water. The bottle spun around rapidly, letting out cold nitrogen gas from the straws like a sprinkler. We learned that water transfers heat, so when the bottle of nitrogen was placed into the water, the gas in the bottle quickly heated up. The gas then expanded rapidly, building up a huge amount of pressure in the bottle.The gas needed to escape. It escaped through the two straws which were placed opposite each other, out of the top of the lid of the bottle. When the gas poured out of the two straws, it caused the bottle to spin around. Ben told us that this was an example of Newton’s Third Law of Motion which states that, ‘For every action, there is an equal and opposite reaction’,
Even though there were many explosions and squeals of delight (or fright) during the incursion, all of us will now not forget Newton’s third law of motion. ‘For every action, there is an equal and opposite reaction.’