0:23:50 > 0:23:57.
0:24:02 > 0:24:04STUDIO BELL RINGS
0:24:04 > 0:24:08Oh, deary me. I wonder where McCork is? It's getting late.
0:24:08 > 0:24:11Colin, did you know that scientists in Europe have
0:24:11 > 0:24:14invented a plane which runs completely on solar power? How cool!
0:24:14 > 0:24:16That's amazing, Doctor.
0:24:16 > 0:24:19I wonder what sort of fuel Professor McCork is running on today.
0:24:19 > 0:24:22HE MURMURS APPRECIATIVELY
0:24:24 > 0:24:26Ten seconds to air, everyone.
0:24:26 > 0:24:27Ohhh!
0:24:27 > 0:24:29HE BURPS
0:24:29 > 0:24:31Oh, excuse me.
0:24:31 > 0:24:34- DRAMATIC VOICEOVER: - This is Brain Freeze.
0:24:34 > 0:24:36With Dr Knowles...
0:24:36 > 0:24:38Professor McCork...
0:24:40 > 0:24:43..and Colin, the floor manager.
0:24:43 > 0:24:46Stand by.
0:24:53 > 0:24:55Hello, everyone, and welcome to Brain Freeze.
0:24:55 > 0:24:59And let's reveal...
0:24:59 > 0:25:02Today we're asking...
0:25:02 > 0:25:06Ah, do we have to talk about this, Dr Knowles? I hate flying.
0:25:06 > 0:25:08It's OK, Professor. Relax.
0:25:08 > 0:25:12There are four main factors involved in getting a plane off the ground.
0:25:12 > 0:25:14Please tell me none of them is luck.
0:25:14 > 0:25:16These are...
0:25:20 > 0:25:22Thrust is the force that moves the aeroplane forward.
0:25:22 > 0:25:25It is generated by the plane's engines or propellers
0:25:25 > 0:25:28and overcomes the drag force present in the air.
0:25:28 > 0:25:30Remember, air isn't nothing.
0:25:30 > 0:25:33It's a mixture of gases that the plane has to push through.
0:25:33 > 0:25:36So, it's like riding a bike in the wind blowing in your face or
0:25:36 > 0:25:38- something?- Something like that, Professor.
0:25:38 > 0:25:40Ah, see, I'm not just a pretty face!
0:25:42 > 0:25:46But before we take off, a quick word from our sponsors. Stay tuned.
0:25:46 > 0:25:48DRAMATIC OUTRO
0:25:48 > 0:25:51And we're clear! Are you looking forward to your trip, McCork?
0:25:51 > 0:25:54I am indeed. New York city.
0:25:54 > 0:25:56The World Hot Dog Eating Championships.
0:25:56 > 0:26:00- Months of training finally about to pay off.- Oh!
0:26:00 > 0:26:02It's been so long since I've had a holiday.
0:26:02 > 0:26:06The thing is, I've no idea how I'm going to get there. I hate flying.
0:26:06 > 0:26:11- Well, they say it's perfectly safe. - I was thinking maybe I could drive.
0:26:11 > 0:26:12CAR HORNS TOOT
0:26:12 > 0:26:15Ah, no, strike that. Maybe I could swim?
0:26:15 > 0:26:19- Not after eating all those hot dogs, Professor.- Yeah, true enough.
0:26:19 > 0:26:21Here, I could try taking one of them jet skis.
0:26:21 > 0:26:23Help! Oh! Help!
0:26:23 > 0:26:24Ooooh!
0:26:24 > 0:26:27Well, I'm sure you'll figure something out, McCork.
0:26:27 > 0:26:30Places please, everybody.
0:26:30 > 0:26:32Just in from Frank.
0:26:32 > 0:26:35If thrust makes the plane go forward, what makes it go up?
0:26:35 > 0:26:38Aeroplane wings are designed in a special way.
0:26:38 > 0:26:40They're curved on top and flatter underneath.
0:26:40 > 0:26:43The air moving over the curved part of the wings flows faster than
0:26:43 > 0:26:46the air at the bottom, creating a difference in pressure
0:26:46 > 0:26:48resulting in an upward lift force.
0:26:48 > 0:26:51This lift force combines with the forward thrust of the engines to
0:26:51 > 0:26:55- overcome the drag force of the air.- Ah, finally.
0:26:55 > 0:26:58But there is one other force at work - gravity.
0:26:58 > 0:27:01Gravity is the special force that pulls all of us down
0:27:01 > 0:27:03on the Earth's surface.
0:27:03 > 0:27:06When the upward lift force created by the wings is greater than
0:27:06 > 0:27:09the force of gravity pulling the plane back to Earth,
0:27:09 > 0:27:11it's time to fasten those seatbelts!
0:27:15 > 0:27:17So, now you know how an aeroplane flies.
0:27:19 > 0:27:23Lift has to overcome gravity and thrust has to overcome drag.
0:27:23 > 0:27:24And I have to overcome fear.
0:27:24 > 0:27:27That's all for today's show. See you next time.
0:27:27 > 0:27:29DRAMATIC OUTRO
0:27:29 > 0:27:32And we're clear. Phew! Great show, guys.
0:27:32 > 0:27:36Maybe I could ride a whale over or jump on a dolphin's back or
0:27:36 > 0:27:40- maybe I could get a TARDIS like yer man, Doctor Who.- Oh, look at this.
0:27:40 > 0:27:44- Cheapskate Airways. Flights to New York for 25.- Ah, that's magic.
0:27:44 > 0:27:47- Book me in, so, Doctor.- But, wait.
0:27:47 > 0:27:51- I thought you were afraid of flying? - Well, a bargain's a bargain, Colin.
0:27:51 > 0:27:52Oh, McCork!