The Most Amazing Thing About Trees

Hope this was worth the wait! So many people helped with this video: Prof John Sperry, Hank Green, Henry Reich, CGP Grey, Prof Poliakoff, my mum filmed for me in beautiful Stanley Park and Jen S helped with the fourth version of the script. Prof John Sperry http://biologylabs.utah.edu/sperry/john.html Hank Green (SciShow) http://www.youtube.com/user/scishow Henry Reich (minutephysics) http://www.youtube.com/user/minutephysics CGP Grey http://www.youtube.com/user/cgpgrey Prof Poliakoff (Periodic Videos) http://www.youtube.com/user/periodicvideos Also thanks to the Palais de la Decouverte - they helped me with the whole vacuum pump setup in Paris. No, I could not actually suck water up 10m - I did about 4m, but the vacuum pump was easily able to do it and I saw spontaneous boiling on all of our various trials. Footage from this may end up on 2Veritasium. Trees create immense negative pressures of 10's of atmospheres by evaporating water from nanoscale pores, sucking water up 100m in a state where it should be boiling but can't because the perfect xylem tubes contain no air bubbles, just so that most of it can evaporate in the process of absorbing a couple molecules of carbon dioxide. Now I didn't mention the cohesion of water (that it sticks to itself well) but this is implicit in the description of negative pressure, strong surface tension etc.

Comments

1. how does the tree eliminate gasses from the groundwater?
2. Can someone please explain negative pressure? It's counter-intuitive..........
3. Than why we cut all the trees out?
4. Imagine if trees had muscles doe. America''s trees would be under steroids and in herds.
5. I remember an old disney cartoon featuring mickey mouse where a giant uses trees as straws. Actual consultancy? Or happy accident?
6. Hi science guy from crash course. I like the other brother better. He is featured in his own thought bubbles.
7. WOW! Amazing!
8. That lady in the back when Hank started talking about cow udders. EDIT: 1:42
9. Hydraulics?
10. i would think the evaporation of all that water also plays a part in the cooling of the leaves
11. I love tree's ; )
12. so trees are a factory of oxygen and clean water! wow
13. TREES....
    
    I HATE TREES...
    You can never tell if they're just spytrees or killertrees or just boring stupid regular trees! i'll-Ill just be wondrin' round - like r-round my park and just... like BLAM! A spytree! That.. actually happened!
14. wow. this is one of the very most informative and mind blowing videos of yours
15. So if u cover the top of a Tree you can catch all the evaporating water and send it back to the bottom ?
16. I know something else that's super sucked
17. trees are weird, man
18. Water is not just used for a couple of carbon molecules. I read it's also used for photosynthesis and cooling trees since chemical reactions increase the temperature of the tree, so does the sun. And who knows if water evaporation is used for more purposes ^^.
19. So why doesn't the tree suck air in at 16atm of pressure if you snip their tip? In addition, why doesn't simple damage just destroy that internal pressure, killing the tree from a single cut?
20. Trees!😍