Autumn quiz: a time for change

Our teams this month are atmospheric climate scientists Ella Gilbert and astronomer Matt Bothwell, and climate economist Gernot Wagner and ethonobotanist Cassandra Quave.

Chris - Now as we always do on these programmes, we like to pause halfway and test the mettle of our panel with a quiz. And of course you at home can try it and see if you can have a bigger brain than they do, because you are competing, everybody, for a prize beyond prize this week. It is the Naked Scientist 'Big Brain of the Week' award that you're going to win. So there are going to be two teams and team one is Ella and Matthew, team two, Cassandra and Gernot. Now there are three rounds to this quiz and conferring is actively encouraged because each team's going to get different questions. So do talk between yourselves and establish what you think the answer is. We won't be awarding marks for - unlike your maths paper at the exam - showing your working. But we do like to hear it all the same. For you at home, this is your chance to see if you can outwit our panelists.

Chris - Now because the seasons are changing and here in the Northern Hemisphere, we are heading into autumn, we thought a good theme for the quiz would be 'change'. So let's do round one first: 'too hot to handle'. This is a change in temperature. Question one, which of these elements will melt in your hand? A) gallium B) bromine or C) mercury?

Matt - I think bromine is a gas at room temperature. So it's not going to be that.

Ella - I wouldn't fancy handling any mercury.

Matt - Dredging this up from the depths of my memory, it might be gallium. I'm not sure I'm more than 50% sure.

Ella - Well, that's more sure than I am.

Chris - Is that what you're going for?

Ella - Yeah. Why not?!

Chris - Yep. Well done. It is gallium. Gallium is a soft metal. It's a silvery color as most metals are, and it will melt to a liquid at any temperature which is higher than 29.76°C. Of course, your body temperature at 37°C, give or take, means your hand temperature is capable of melting gallium. Bromine and mercury are already liquids at room temperature, so if you have them in your hand, unless they're starting off extremely cold and that wouldn't be pleasant to hold, they wouldn't be naturally melting in your hand. Right! One so far to Matt and Ella.

Chris - Team two: Gernot and Cassandra, here's your question. Verkhoyansk in Russia is the place on Earth with the greatest range between its highest and lowest recorded temperatures. Is it A) 66°C, B) 86°C or C) 106°C? What do you think?

Gernot - Okay. So a hundred is a bit high, right? We are talking minus 40 to plus 60. That doesn't quite sound right. So how about the middle one here?

Cassandra - Yeah, I concur. We'll go with that. We'll go with the middle.

Chris - You're going 86 degrees. I'm afraid, no, the answer is actually 106. Verkhoyansk is home to over a thousand people. It holds the record for being both the hottest and coldest place at different times. And it has the widest temperature range, therefore. It's recorded a scorching 38°C on some occasions and a brisk, shivery -68°C on others. So 166°C.

Ella - I was sitting on my hands the whole way there because I knew that.

Chris - Oh, there you go. Now you know why we didn't make you team two!

Gernot - That seems hot!

Cassandra - I'm thinking of their closet? What kind of clothes? I mean, how do you prepare for a year like that?

Ella - Two wardrobes!

Chris - You need two wardrobes, quite right Ella. Right. Ella and Matt back to you. Your question: salmon are famous for swimming upstream from the ocean along rivers in the autumn to reach their spawning beds. This is a race called the salmon run, but what's the average speed that sockeye salmon doing that migration do on the Fraser River? Is it 0.9km/hr? Is it 2.4km/hr? Or a speedy 6.8 km/hr? What do you think?

Matt - This feels like a Monty Python question to me.

Ella - It really does! It depends how fast the river is! I feel like maybe the middle one.

Matt - Yeah. Like based on nothing but intuition, just throw the data at the map, the middle one...

Ella - 6km/hr is fast.

Matt - Like that is pretty fast rate.

Chris - Well a fast shark or a tuna will do 60 or 70 km/hr.

Ella - Yeah, but this is an average, right? Are they going like uphill up rapids? That's what you always see in the nature docs, isn't it? Bears leaping at them.

Matt - Yeah, faster than walking pace seems fast for an average.

Chris - Matt's going for a more sedate two and a half kilometres an hour. Is that your answer?

Matt - I'm imagining a pretty chilled out salmon going down the river, you know?

Chris - The public astronomer says 2.5km/hr seems like a sedate speed for salmon seems good. And you're absolutely right. Yeah. It is actually 66.75 centimeters per second. It's been demonstrated that the most efficient speed to travel at, if you are a sockeye salmon, is 1.8km/hr, but that wouldn't work if you were going to miss the festivities and not get to your spawning beds in time. So that's why they swim a slightly less sedate two and a half kilometers per hour.

Chris - Cassandra and Gernot, back to you. Your question is: Mars has a longer orbit around the Sun than we do here on Earth. And Matt you'll know why you didn't get this question. It means that the seasons are longer on Mars. To the nearest whole number, how much longer are the seasons on Mars? Are they A) twice as long, B) three times as long or C) four times as long as they are on Earth?

Cassandra - I don't know. I wonder how far is Mars from Earth? Maybe that could help. I know it's really far!

Matt - Miles is tilted by about exactly almost the same tilt as Earth. So it has seasons for just the same reason.

Cassandra - That's great. Can we phone a friend? I want to have Matt!

Chris - Matt's not going to help you here I'm afraid!

Gernot - Wait, so one of the options was twice as long, right?

Chris - You've got twice as long, three times as long or four times as long. What do you think?

Gernot - Twice as long.

Chris - You're going twice. Do you agree, Cassandra, you're going twice?

Cassandra - We'll go with twice

Chris - Correct! One Martian is 687 days, and that's almost twice as long as an Earth year, so the seasons are roughly twice as long. As Matt says that Mars is tilted in the same way with roughly the same inclination that the Earth is, which is why it has seasons, and therefore they're roughly in proportion to the Earth seasons as well.

Gernot - So is that why Elon [Musk] wants to go there just to have every year be twice as long?

Chris - The thing is you come home and you're only aged by half as long. If you believe that you believe anything.

Chris - Right. Round three. This round is called 'a change in time: it goes by so slowly'. Question to Ella and Matt. Getting a handle on different time zones is important in the time of online communication, but over the last couple of years, no one has really made any drastic changes of them for the sake of zoom calls for instance. But that wasn't the case in 2011, when which island decided to jump ship and skip a day out of their calendar, which the victim was the 30th of December to jump across the international date line and become one of the first countries to see in the new day of that year and the subsequent new year, of course, rather than one of the last. Was it Samoa, Fiji or Tonga?

Ella - I remember this happening and I can't remember which one it is.

Matt - Yeah, same. I watched a YouTube about this quite recently because they wanted to be able to do business with Australia, right? Because I think the problem was it was Friday for the islands and it was Saturday in Australia. So they couldn't do business with them.

Ella - I can see why that was a problem. I don't think it's Fiji. I don't. I'm not basing that on anything sensible. That's just a gut feeling for Samoa, but...

Matt - Yeah. Then let's go with your gut feeling.

Chris - And it's a good call! It is Samoa! Well done. The dateline runs across the Pacific Ocean. It separates one day, literally, from another and American Samoa is on the eastern side of the date line and that means that those two regions are separated by a whole day, even though they're only 30 miles apart. Well, that puts you in a very much unassailable position, I'm pleased to say, for you Matt and Ella. It does mean that for Cassandra and Gernot, it is a winning streak, not for you this week, but I'll give you the last question anyway, because this is your opportunity to partially redeem yourself.

Chris - I hope you know about koalas. When a koala is born, it's about the size of a jelly bean. It's got no hair, no ears and it can't see. But how long is a koala's gestation period? In other words, how long is it pregnant for? 7-14 days, 28-35 days, or 63-70 days? What do you think?

Cassandra - Okay. Let's think about this. I think they're so tiny, right? And they kind of mature outside of...

Gernot - Yeah. Shorter, I believe, but frankly... My wife's a human gynaecologist, so I wouldn't be able to... What was the middle one?

Chris - Seven to 14 days, 28 to 35 days, or 63 to 70 days.

Cassandra - I mean, you go from a cell to like something that would be large enough. I would say like at a minimum would be 28 days, I think. Right. Like to get to a decent enough size to survive outside.

Gernot - With 28 to 35 for the prize?

Cassandra - Yeah. Yeah. I think so.

Chris - And it's a good call to make because it's the right answer. Yes, it is 28 to 35 days. Very well done. Unfortunately you are not the Naked Scientist Big Brain of the Week Award winners this week because that accolade goes to Ella and to Matt. So let's give them a round of applause. Well done guys. Excellent demonstration of knowledge of time and change.