How to listen to this Science Experiment
Steve Spangler does a lot of science experiments. ESL students enjoy listening to him because he often works with children, so his explanations are simple. But, while the explanations are simple, he speaks quickly. He speaks so quickly that sometimes he decides to change his sentence in the middle.
For example, in the link below, he says: “The liquid nitrogen’s a liquid, most of the air…” This would be a strange sentence to write, but people say strange things or change their sentences in the middle all the time. So, it’s good practice to listen to someone like Steve. Practice focusing on the important things and ignoring the strange things. You can do it in your language, so you can do it in English too.
Other than a few technical terms, the vocabulary is not too difficult. Listen three times. Then take a look at the discussion questions and answers below. Finally, you can read the transcript at the bottom. But listen several times and answer the questions before reading.
What is liquid nitrogen?
Is nitrogen poisonous?
What happens while the liquid nitrogen is in the bottle under the barrel?
Why does the barrel fly into the air?
What is liquid nitrogen? Nitrogen is normally a gas, but if it is very cold, then it becomes like water (a liquid).
Is nitrogen poisonous? No, most of the air we breathe is made of nitrogen.
What happens while the liquid nitrogen is in the bottle under the barrel? It expands. It becomes 700 times bigger. When liquid nitrogen becomes a gas again, it needs a lot more space. But, it’s in the bottle, so there isn’t a lot of space.
Why does the barrel fly into the air? When there is too much gas in the bottle, it explodes. The explosion sends the barrel into the air.
Alright, so Ellen this is what we did in our office. We’re pouring the liquid nitrogen in here, and I mention it because the police actually came out a little bit because they thought that maybe shots had been fired. The liquid nitrogen’s a liquid, most of the air that we breath is nitrogen, so it goes down inside here, but it expands 700 times its normal size. So, here’s the liquid nitrogen here. Now, Jeff’s going to cap it off, and it goes into the barrel that you see here, and so this goes in, and we thought that we’d just kind of put this over the top. So this goes over the top, and now the liquid nitrogen’s getting bigger and bigger, and that bottle is expanding, and it’s getting bigger and bigger and bigger until finally you get this pressure that starts to release. It’s the same thing that we used to use in a steam engine, you know years ago, or on a propane tank there’s a pressure release valve. But, it’s, you can actually hear it inside…[BOOM!]…so that’s what happens. You just kind of, release the pressure. Isn’t that awesome? Back to you, Ellen.