Kind: captions
Language: en
[Applause]
Trees are some of the biggest organisms
on the planet. But where do they get
that matter to grow? Which nutrients out
the ground? Just out the soil. Really?
Yeah. Goodness out of the soil. I
suppose comes out of the soil. Yeah.
Yeah. Goodness. Goodness. Why isn't
there a big hole around the tree where
it's taken out all the soil? Does it say
gradually that the soil has time to
recover?
Now, I think it's intuitive to believe
that the tree gets most of its mass from
the soil because you can see those roots
digging into the soil and they must be
taking something out of there. And I
mean, a tree looks like dirt and it
feels solid like dirt, but it's not. In
the early 1600s, a scientist named Johan
Baptista Van Hemhalt tried to figure out
where the mass of a tree was coming
from. So, he got a pot of soil and very
carefully measured the amount of soil in
there. Then he planted the tree and took
care of it for 5 years, making sure that
no soil left or was added to his pot.
And at the end of this experiment, he
weighed the tree to find that it was 72
kg, but the mass of soil had only
decreased by about 60 g. This was pretty
strong evidence that the mass of the
tree does not come from the soil. I've
never thought about that actually
because they don't really eat anything.
Trees, they don't eat anything. No, they
don't eat anything. Water is all they
absorb. That's all they eat. Yeah, they
don't eat anything else. No, that's all
they eat. Well, presumably from the
water and the nutrients from the soil.
Is there anything else that you need
besides the soil and the water? I
suppose that's all you need, isn't it?
To make other other than the original
seed
for for that particular tree, I suppose.
The seed and the soil and the water and
that makes this big tree.
Of course, Johan Baptista Van Hemhalt
did conclude that the tree was made
entirely of water. Now, while that's not
correct, at least he was on the right
track realizing that the matter of a
tree doesn't come out of the soil. The
sun energy. Yeah. The sun energy. Yeah.
Are they converting energy into mass or
do you know what I mean? Yeah. I don't
know. Like there wasn't there wasn't
stuff and then there was like where did
that stuff come from? Magic.
I don't know. My question is where do
they get that mass to grow big? Sun. Is
it from the rain and the sun presumably?
Light. A sunlight. And the sunshine. The
sunshine. Does it Does the sunshine add
mass to the tree? Um,
they seem to need to have sunshine.
Well, it Yes, it wouldn't. They wouldn't
grow without it. I don't know whether it
adds mass, but they wouldn't grow
without it. Of course, the sun's energy
is needed for the tree to build the
matter into its branches and leaves, but
the sun itself, the energy is not
matter. Well, I suppose you got to put
air into this as well if you're Yeah,
there's got to be something out of the
uh you know, what is it about? A gas in
the air that it leaves as well. Oxygen.
The trees need the oxygen. Yeah. Need
the oxygen, don't they? And uh I guess
oxygen. The oxygen. bus the oxygen.
Yeah. Are there any ingredients that
we're missing? Um, carbon dioxide.
Carbon dioxide. Carbon dioxide. So,
would it surprise you to find out that
95% of a tree is actually carbon dioxide
from carbon dioxide? Trees are largely
made up of air. Yeah. Surprising. Yeah.
I I need this reaction like
So, as it turns out, trees are mostly
made out of air. out of the carbon
dioxide that they take in. And what's
interesting is that we breathe out
carbon dioxide and water. That's how we
lose mass. But it's the exact same
substances that trees breathe in to gain
mass. So if you can imagine a closed
system where it was just you and a tree,
you would breathe out that carbon
dioxide and water. The tree would take
it in. So you would get smaller while
the tree is getting bigger.
And in a sense, you're becoming the
tree.