and that drive people to move into the does it. during the focus season they'll have access to water but what happens in summer from december to march when there's almost no fog the satellite is a planning a reservoir for folks water so they won't have to buy so much. but even if you're back in touch no one call us apart has plucked. a boat crews and colleagues from the peruvians without water project checking the direction of the wind to ensure the nets are in the right position. cruz has given lectures at universities and won awards around the world for his pioneering work he's determined to help more poor communities in dry regions look at their most what do plants need to grow is arid enough you know they need water and we get it from the clouds and it's free the families here don't even have enough to eat they can't afford to buy water. about cruz says sutter over

a 1000 fold catches in peru with more planned until everyone who needs to capture clout. consider a standard drop of water like the one used in medicine 500 other millipedes here or gram. it contains 56 trillion asked him that 5 with 210 s. there were 2 hydrogen atoms and one oxygen atom in every war somalia killed our viewer khalifah keys has a question about all this. what is an atom. everything around us everything we can see feel smell or taste is made up of atoms and of course we are 2. terms are the building blocks of matter. that sums out that spatial arrangement give matter

its properties such as consistency and color. the way we think about atoms today is largely influenced by physicist niels bohr's model according to which electrons orbit the atoms nucleus. a bit like planets orbiting the sun. was better can't be seen with the naked eye the fitness of a human hair. is $500000.00 times the diameter of a carbon atom. in the center of the atom is a tiny nucleus containing neutrons which have no electric charge and protons which have a positive charge. 2 2 the electrons orbiting outside are negatively charged the only out of not to have any neutrons is hydrogen it consists of one proton and one alectryon. just as stars have different numbers of

planets orbiting them atomic nuclei have different numbers of electrons in orbit. in the neutrally charged atom the number of electrons equals the number of protons . and the number of protons determines the chemical elements so far we know of 118 they and many of their properties are displayed in what's known as the periodic table of the elements. if outlet is red why are platinum even if you. do you have a science question that you've always wanted answered we're happy to help out with a little ass as a video text ovoid smell if we answer it on the show we'll send you a little surprise as a thank you can i just ask. you'll find is that i did have a dot com slash science or drop us a line at e.w. underscore site tech on facebook d w dot science. if you put

a specific extremely large number of silicon atoms together to create this fear of a certain size it will weigh exactly one kilogram scientists have succeeded in doing that and why to define what a kilogram is in terms of a natural constant in this case the of a god or a constant. it's a way to check the accuracy of another new definition in terms of the planck constant this has really. simply been adopted as the official definition of world wide difficult stuff but it is important anyway to take the measure of things. it's a weighty matter welcomed the new kilogram we now take a look at a project based on that new official definition. since 2017 thomas relation his team at the technical university. have been working on

a new set of scales together with germany's national maturity institute they've developed 2 prototypes based on the new definition of the kilogram. for 130 years a metal cylinder in paris was the world's benchmark of the kilogram but not any more just your home for the kilogram was the last remaining unit based on a physical object a piece of metal and all other units are based on constants of nature. and beauty notably so in that speech because of this redefinition weights are no longer derived from the international prototype kilogram stored in a safe in paris. instead they're derived from a fundamental constant constant but 1st things 1st. in the past all weights used to calibrate scales worldwide whether it was in

pharmaceutical companies biotech labs or supermarkets all derived from a platinum iridium cylinder located just outside paris stored securely under 3 glass bell jar extremely precious object was kept in the safe of the international bureau of whites and measures from $889.00 until this year it was the defining unit of mass worldwide but for some unknown reason the parents kilogram decreased in white by 50000000. of a gram so scientists decided to take action in a historic move they redefined the kilogram. this time they're not using a metal object but a constant of nature the planck constant denoted by a small age described for the 1st time by max planck around 1900 so what is the planck constant. mccance just dance and before you can think of it has the smallest

possible unit of energy consider the energy coming out of a car battery or an electric socket on the walls and if you were to divide that into lots of small amounts the smallest possible amount would be the plug constant it's a fundamental constants of nature it's involved in many aspects of physics. one reason why we can't take the planck's constant as the definition of this mass is because the planck constant can be expressed in terms of the kilogram and 2 other as a unit that's why we were able to establish a relationship between the value of the cube a gram and the plank constant so any of. this can be done using a watch balance for example it's a highly complex instrument that's been used since the 1980 s. to measure the planck constant as precisely as possible. there are only a handful of these scales worldwide this one is in the united states at the

national institute of standards and technology. the high precision scale is based on the principle of electromagnetic force compensation this is how it works the gravitational force of a test mass is balanced with an electromagnetic force the magnetic field is provided by a permanent magnet a coil of wire is immersed in that field. it's like a coil in a loudspeaker and the coil is in a permanent magnetic field an electrical current is run through it to generate a force that force is used to balance the downward force of the weight it's a way to measure weight using an electrical current. in other words the electrical current is adjusted until the upward force on the coil perfectly balances the downward force of the weight the 2nd step is called the velocity mode

a precision laser called an interferometer shown here in green is used to measure the position and velocity of the coil. the aim is to measure the voltage that is created in the process. then we need gravitational acceleration small g. 9.81 meters per 2nd per 2nd if you know all these things very precisely you can calculate the numerical value for h. the math isn't complicated in reverse if you know the value of h. the planck constant you can specify a kilogram. the planck scales from germany will work in exactly the same way they're basically a what a balance on the left is the laser interferometer on the right is the balance based on the principle of electromagnetic force compensation but it's a lot smaller than its american counterpart. if i reverse the principle of the

water balance and say i know the value of h. then i can use my playing scales to calibrate anyway the. i simply made my object on the one side and then relate to electrical values to the plumb constant and from that i can calculate the mass on the scale. of. the 2 planck scale prototypes from the technical university elma now will eventually be put to industrial use currently they can be used to determine weights in the range between one milligram and 100 grams but it will be another 3 to 5 years before the 1st planck scale goes to market the paris kilogram meanwhile has already lost its status as the international benchmark and is now being consigned to a museum. along with the kilogram the 2nd and the meter they are all sorts of are the units of measurement we asked our viewers what units of measurement do you. seth

wrote the indigenous people of mexico use the media which is equal to the volume of an empty sardine can. show from indonesia says in java we often use the volume of an empty coconut shell to measure rice maize and other goods one shell usually holds one kilo. this unit of measurement is still in use today. in argentina says we use the nice or kilo celsius liter and hector pascal or we i bought it that always works. says our says farmers in colombia use the key took the distance you can travel while smoking a cigar so where is the farm one and a half to go from danya is stuck here as farm thanks for your comments. that's all for today next week we head to colombia as we continue our journey in

the footsteps of humbugs he wrote that slavery was the greatest of all evils to have to fall in humankind with us of the town of palenque a established by scott slaves 400 years ago until then good bye.

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tasty taipei starts september 1st on t.w. . earth home to millions of species. forced savings. googling to tell stories of creative people and innovative projects around the world like deals the protect the climate boost green energy solutions and reforestation. interactive content to inspire people to take action global audience the series of global 3000 on t.w. and online but.

this is deja vu news live from berlin some surprise comments from u.s. president donald trump at the g. 7 summit in france at an impromptu news service he said he's had a conversation with china that could change the outlook for their trade dispute he also has a big news on iran we'll go live to be arrests also coming up. a new level of violence in hong kong after police fire a full warning shot yet. is the 1st time they've used live ammunition authorities say the situation is becoming very dangerous kind of thing day in the bundesliga for a rising star wipes a striker. signs a new contract and scores

a goal as his team continue their perfect start to the season. i'm brian thomas thanks so much for joining us the g 7 leaders are heading into the final day of their summit in the french resort of beer it's today's meetings are expected to focus on climate change and the fires burning in the amazon in brazil now in the course of the last hour u.s. president. held an unscheduled news conference at that summit sitting alongside the egyptian leader abdel fatah el-sisi tom touched on a number of key issues including the middle east and iran more on that in a moment on the dispute with china he had this to say. very very good.