0:00:12 > 0:00:15Hi, guys, Martin here with your Tuesday Newsround.
0:00:15 > 0:00:18First up, spies, computer hackers and Russia.
0:00:18 > 0:00:19What's going on?
0:00:19 > 0:00:22Well, the British Prime Minister Theresa May has made a big speech
0:00:22 > 0:00:24telling off Russia for getting involved in other
0:00:24 > 0:00:25countries' business.
0:00:25 > 0:00:34Ayshah has more.
0:00:34 > 0:00:40Do you know who this is? Mrs Vladimir Putin and here's the
0:00:40 > 0:00:45President of Russia. He likes to the Russian people how strong he is by
0:00:45 > 0:00:51riding a horse are catching big fish. We all need a hobby. Spies
0:00:51 > 0:00:58around the world are getting fed up with what they say he is up to.
0:00:58 > 0:01:03Those spies are saying that Russia is using social media to try to
0:01:03 > 0:01:07interfere in other countries including elections. Experts believe
0:01:07 > 0:01:13teams of Russian spies are writing and spreading stories all around the
0:01:13 > 0:01:19web that are made to divide people and cause arguments. They have
0:01:19 > 0:01:23thousands of social media accounts that all shared each other's stories
0:01:23 > 0:01:27so the messages go far and wide. It is like having thousands of digital
0:01:27 > 0:01:34spies. So what about Vladimir Putin? He says he doesn't know anything
0:01:34 > 0:01:39about it and if it is happening it is nothing to do with them or Russia
0:01:39 > 0:01:44but not everybody believes it and lots of leaders want to know if
0:01:44 > 0:01:47Russia is a friend but if it could be an enemy.
0:01:47 > 0:01:48Next up and it's "Arise, Sir Mo!"
0:01:48 > 0:01:51Team GB Olympic hero Mo Farah went to Buckingham Palace today
0:01:51 > 0:01:53to receive his knighthood from the Queen.
0:01:53 > 0:01:54The long-distance runner was knighted for services
0:01:54 > 0:01:58for athletics and being the only man to win the 5,000m and 10,000m gold
0:01:58 > 0:02:01medal at two Olympic games.
0:02:06 > 0:02:08Here at Newsround HQ we try to answer some
0:02:08 > 0:02:09of life's big questions.
0:02:09 > 0:02:10So that got me thinking.
0:02:10 > 0:02:13And I wanted to know "how do you measure a mountain?"
0:02:13 > 0:02:16Well guess what - smarty pants here only went and found out!
0:02:19 > 0:02:21Mountains!
0:02:21 > 0:02:22Mountains!
0:02:22 > 0:02:24Mountains!
0:02:24 > 0:02:25Lets be honest, they are pretty huge.
0:02:25 > 0:02:28So, how do you measure a mountain?
0:02:28 > 0:02:32I'm guessing a giant tape measure isn't an option?
0:02:32 > 0:02:34Well, there are three main ways that scientists can
0:02:34 > 0:02:37try to measure a mountain.
0:02:37 > 0:02:40The first way is the traditional way, in which it uses maths.
0:02:40 > 0:02:44Yep, you heard me.
0:02:44 > 0:02:46It is useful after all.
0:02:46 > 0:02:52Scientists use something called trigonometry,
0:02:52 > 0:02:55which uses triangles to figure out the height of an object.
0:02:55 > 0:02:58For example, they put a point at the top of the mountain,
0:02:58 > 0:03:02at the bottom, and a point next to it to make a triangle.
0:03:02 > 0:03:06Then, by working out how big the angles are inside the triangle,
0:03:06 > 0:03:08it means they can work out its height.
0:03:08 > 0:03:10However, this method is not super accurate.
0:03:10 > 0:03:11The second way uses global positioning satellites,
0:03:11 > 0:03:16or GPS for short.
0:03:18 > 0:03:21Like the maps on your phone or sat-navs in cars.
0:03:21 > 0:03:27And it is one of the most accurate measures.
0:03:27 > 0:03:30It involves a team of scientists hiking up a mountain carrying
0:03:30 > 0:03:31a satellite receiver device with them.
0:03:31 > 0:03:33When they reach the top, a satellite in space can
0:03:33 > 0:03:35pick up the location.
0:03:35 > 0:03:38However, although it is very good at figuring out where they are,
0:03:38 > 0:03:48it is not so great at figuring out how high they are.
0:03:51 > 0:03:54So the team has to stay in the exact same spot without moving for around
0:03:54 > 0:03:57several hours for the satellite to collect all the data it needs
0:03:57 > 0:03:59to figure out their heights.
0:03:59 > 0:04:00But this method takes a long time.
0:04:00 > 0:04:03It is a bit tricky to measure every mountain this way,
0:04:03 > 0:04:04which brings us on to...
0:04:04 > 0:04:05Method three.
0:04:05 > 0:04:06Photogrammetry.
0:04:06 > 0:04:07Pretty fancy, eh?
0:04:07 > 0:04:10It involves flying over a mountain and taking lots and lots of super
0:04:10 > 0:04:12high quality photographs.
0:04:12 > 0:04:15These pictures can then be uploaded to a computer which uses special
0:04:15 > 0:04:21software to create a 3-D model of the mountain.
0:04:21 > 0:04:23From this, scientists can work out its height.
0:04:23 > 0:04:25This means that mountains in harder to reach areas can
0:04:25 > 0:04:29be mapped more easily.
0:04:29 > 0:04:29This
0:04:29 > 0:04:32So, after all that, we have learnt that it is really tough work
0:04:32 > 0:04:35measuring a mountain.
0:04:36 > 0:04:38Now we want to hear from you.
0:04:38 > 0:04:40What Big Questions would you like us to answer?
0:04:40 > 0:04:44Head online and send us an idea - we might have a go at
0:04:44 > 0:04:48trying to explain it!
0:04:48 > 0:04:51That's it from me guys, Newsround's back at 7.40 tomorrow morning.
0:04:51 > 0:04:57Don't forget to head online to check out the rest of the days stories.