Scales in space and time

Introduction

In science, people encounter a huge range of scales both in space and time. These scales can be difficult to appreciate because they are beyond the range that the human body can perceive. For example, it is possible to measure timescales that are much longer than a person will ever live, and items that are far too small to see. In this short course, to deepen your appreciation of scales, you will explore both familiar scales and the extremes of what humans can measure.

Across multiple scientific disciplines, from biology and chemistry to physics and geology, time scales are explored that include ages, durations and rates, and size scales including distances in three dimensions, which underpin areas and volumes. In this short course, you will use an interactive ‘size–time explorer’ tool to help you get to grips with these ideas, and at the same time you will learn about the interconnections between multiple science disciplines.

An oak tree is a central feature in the size–time explorer. In the video below, different scientists introduce themselves and discuss how their subject area relates to an oak tree, at the same time talking about some of the different scales at which they work.

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Transcript

[MUSIC PLAYING]

JULIA COOKE

In science, we encounter things that are massive and minuscule, that take a millisecond or millennia. And it can be hard to get your head around these different scales. This is not least because we can measure things that are well beyond what the human body can perceive. This activity is designed to develop a deeper appreciation of time and space scales, and through that, a deeper understanding of science.

An oak tree, like the one behind me, is the focus, is the story that runs through all the different levels and helps us relate from one to the next. But don’t mistake this for a biology activity; let’s hear what all of the scientists think when they look at an oak tree.

JIM ILEY

When I look at this oak tree, I think about all of the unseen chemical activity that’s going on to make it grow. The structural material that holds this tree up is largely cellulose. And that’s made up of lots of little glucose molecules. Those units are tiny, about half a nanometer from end to end. So it takes about 12 billion of them to go from the bottom of the tree up into the crown.

JIM HAGUE

You may think this tree is old, but in fact it’s incredibly young compared with the age of the Universe. Although the tree is biological, there’s a lot of incredibly interesting physics within it. For instance, huge forces hold up the trunk and the branches of the tree. The laws of physics govern the flow of fluid from the roots all the way up to the leaves to sustain life. And the chemistry of the cells in those leaves is governed by quantum physics.

DANIEL BERWICK

I’m Dan Berwick, a molecular neuroscientist interested in the earliest events in Parkinson’s disease. Looking at this tree, I can see it’s affected by disease too. There are galls, strange structures caused by a type of wasp larvae. They’re not unlike cancer. But when I look at the tree, I also think of all the compounds used in medicine. We call this tree the mighty oak because it’s big and strong. But maybe the true power of this tree comes from the small molecules within.

JULIA COOKE

I’m a plant ecologist. And I’m interested in how this tree acquires resources and then what it does with those resources. So how it spreads out its leaves to get sunlight and carbon, how it spreads out its roots to get water and nutrients. How does this change across its lifetime of hundreds of years? And how did this evolve over millions of years? And how this species differs from other species to make it the enduring species it is today.

CALUM MACCORMICK

I study highly excited atoms using lasers and magnetic fields. When I look at this tree, I see that it’s also made of atoms. It’s made of hydrogen, which is created in the big bang, but the heavier elements, such as oxygen and silicon were made in the star which previously occupied this part of the Universe. That star’s long since gone. It’s been replaced by our star, the Sun, which gives energy to the tree in the form of light.

STEPHEN BLAKE

The oak tree has seen the building of the Open University campus about 50 years ago. But way before then, about 10 000 years ago, its predecessors started to colonise the UK following a long period of glaciation. The rocks beneath the soil are even older than that, about 165 million years, and were formed by the accumulation of mud on the sea floor. So to me, the oak tree and its environment is part of a big movie picture extending over many scales of time.

SARAH ALLMAN

Hi. I’m a biological chemist and I’m interested in sugars and their function and disease. To me, this tree is a big pile of bioreactors, making sugars, building proteins, making molecules. In the winter months, low temperatures change the properties of these molecules and the speed of these reactions. Whilst in the summer months, the leaves harvest energy and use this to build molecules. And every year, energy is captured by the leaves and stored as sugars and starches for the following year.

CHRISTOPHER HEATH

I’m a neuroscientist that means I’m very interested in understanding how the millions of cells of the nervous system work together to allow us to do the things we need to do to live. When I look at this oak tree, I think about how similar and how different it is to us. Just like us, this oak tree needs nutrition, it needs water, and it needs to exchange gases with the environment, such as carbon dioxide and oxygen.

It has parents. It has children. And, unfortunately, it too will die. However, unlike us, the oak tree isn’t exactly renowned for its ability to move. Unlike us, the oak tree can pull off one of the greatest tricks of biology: photosynthesis.

JULIA COOKE

Every scientist sees this tree very differently. And that’s because the tree is a product of the evolution of life, of the history of the Universe, the history of the Earth, it’s a potential source of medicines, it’s a pile of bioreactors, it’s an organism that interacts with its environment. And this amazing tree is perfect for exploring scales in space and time.

[MUSIC PLAYING

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This OpenLearn course is an adapted extract from the Open University course S112 Science: concepts and practice [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] .