About Science

1.1

Scientific Measurements:

How much you know about something correlates to how well you can measure it.

The concept of scientific measurements aren’t new.

How Eratosthenes Measured the Size of the Earth:

  • Done in Egypt, 235 BC.
  • Calculated the circumference of the Earth using the summer solstice.
    • Sun is highest in the sky at noon on the day of the summer solstice. [June 21st]
    • At this time, a vertical stick in the ground casts its shortest shadow. When the Sun is directly above it, it doesn’t cast a shadow at all.
    • Eratosthenes learned that in Syene (city south of Alexandria), during this time the sunlight shines directly down a well and gets reflected back up.
    • He figured that the Sun’s rays would’ve passed right through the center of the Earth if there was no obstruction.
    • On June 22nd, he measured the shadow cast by a vertical pillar in Alexandria. It was 1/8th the height of the pillar, which corresponds to a 7.1˚ angle between the Sun’s rays and the vertical pillar. (about 1/50th of a circle)
    • Eratosthenes reasoned that the distance between Alexandria and Syene must be 1/50 times the circumference of the Earth.
    • Or, the circumference of the Earth is 50 times the distance between these two places.
    • The distance came out to be 50*5000 = 250,000 stadia, where 500 stadia is 800 km.
    • Instead of using degrees, if we compared the length of the shadow cast by the pillar to the height of the pillar, we’d get the same result.
    • The pillar is eight times the taller than it’s shadow; the radius of the Earth is eight times the distance between Alexandria and Syene.
  • Circumference of a circle: 2πr, where r is the radius.
  • Earth’s radius: Circumference/2π.
  • Earth’s radius: 6370 km.
  • Earth’s circumference: 40,000 km.

Size of the Moon:

  • Aristarchus, Greek scientist, suggested that Earth spins on its axis once a day.
    • This justified the motion of the stars.
  • He said the Earth and other planets moved around the Sun in an orbit each year.
  • He calculated the Moon’s diameter and its distance from the earth. (in 240 BC).
  • He compared the size of the Moon with that of the Earth by watching an eclipse of the Moon.

*__Eclipse of the Moon __*→ Event in which the Moon passes into the shadow cast by the Earth.

  • The width of the Earth’s shadow turned out to be 2.5 diameters of the Moon.

  • The Moon should’ve been 2.5 times smaller than the Earth, but Earth’s shadow tapers because of how massive the Sun is.

  • Earth barely intercepts the Moon’s shadow. The Moon’s shadow tapers too, nearly to 1 Moon diameter.

  • Earth’s shadow also needs to taper 1 Moon diameter.

  • Taking everything into account, the Earth’s diameter turns out to be (2.5+1) times the Moon’s diameter.

    Diameter of the Moon = Diameter of the Earth/3.5

  • Currently accepted diameter of the Moon: 3640 km.

Distance to the Moon:

  • Tape a small coin to a window and look at it with one eye so it blocks out the full Moon. This happens when the eye is 110 coin diameters.
  • Coin diameter/Coin distance = 1/110.
  • This is the ratio for Moon diameter/Moon distance.
  • The distance from the Earth to the Sun was calculated using this.

Distance to the Sun:

  • If you repeated the coin experiment, the ratio for Sun diameter/Sun distance would turn out to the same (1/110).
  • Reason → sizes of the Sun and the Moon are the same to the human eye. They taper at the same angle (0.5˚).
  • Aristarchus’ method:
    • Watched for the half full phase of the Moon, when the Sun was still visible in the sky.
    • Sunlight falling on the Moon is at right angles (to his line of sight).
    • Conclusion: Lines between the Earth and the Moon, the Moon and the Sun, and the Earth and the Sun form a right angled triangle.

[Rule of trigonometry: You can calculate the length of a side by knowing all three angles and the length of another side.]

→ He knew the distance between the Earth and the Moon.

→ First angle was 90˚ (during the half Moon)

→ Second angle, x, to be measured was between the line of sight to the Moon and the line of sight to the Sun.

→ Third angle = 180 - (sum of the first two angles)

  • Celestial bodies are huge. Aristarchus had to use their rough centers to calculate the angles. Today, his measurements are considered crude.
  • He measured 87˚, the actual value is 89.9˚.

The Sun is an average of 150,000,000 km from Earth.

It’s closer to Earth in December (147,000,000 km) and further away in June (152,000,000 km).

Size of the Sun:

  • Sun diameter/Sun distance = 1/110
  • Another way to measure this: Measuring the diameter of the Sun’s image cast through a pinhole.
    • Poke a hole in a sheet of cardboard, let sunlight shine through.
    • Round image cast below is an image of the Sun.
    • Size of the image depends on how far away the pinhole is.
    • Bigger hole = Brighter image
    • Very big hole → no image formed
    • Image size/Pinhole distance ratio = 1/110.
  • During a partial solar eclipse, pinhole casts a crescent shaped image (like a partially covered Sun).
  • Spots of sunlight on the ground beneath trees are pinhole images of the Sun (light shines through leaves).
    • Tall trees → large images
    • Short trees → small images
    • During a partial solar eclipse → images are crescents

Mathematics - The Language of Science:

  • Integration of science and math advanced civilization.
  • Ideas of science expressed in mathematical terms are unambiguous.
  • Science equations are compact expressions of relationships between concepts.
  • Easier to verify concepts when expressed mathematically.

1.2

Scientific Methods:

  • No one scientific method

  • Common features in the way scientists work

  • Used to work “upward or downward” (Greek method), now scientists work “upward” → observing, then building an explanation.

  • General steps to how a scientist works:

    1. Recognize a question/puzzle (like an unexplained fact).
    2. Make an educated guess (hypothesis) that might solve it.
    3. Predict consequences of the hypothesis.
    4. Perform experiments/make calculations to test these predictions.
    5. Make a simple general rule to organize these three: hypothesis, predicted effects, experimental findings.

  • Trial and error is very necessary in science.

  • Scientific attitude has inquiry, integrity, and humility.

The Scientific Attitude:

Facts:

  • We think of facts as concrete, unchanging, absolute.
  • In science, a fact is an agreement between observers making a series of observations about the same phenomenon.
    • Eg:
    • Once a fact → universe is changing and permanent.
    • Now accepted → universe is always evolving, expanding.

Hypothesis:

  • A scientific hypothesis is an educated guess that isn’t considered a fact until experiments back it up.
  • A hypothesis is called a law or principle if it gets tested and proven repeatedly.
  • If evidence contrary to a hypothesis is found, the hypothesis has to be changed or abandoned - unless the evidence is proven wrong.
    • Eg: Aristotle’s theory that objects fall at speeds proportional to their weight was followed for nearly 2000 years, until Galileo proved him wrong.
  • In normal life, you test things out to see if they’re true. In science, you test things out to see if they’re false.
  • A hypothesis isn’t considered to be scientific if there’s no way to test how wrong it could be.

Reputation Doesn’t Matter:

  • If a scientist’s hypothesis is proven to be wrong from even one angle, it always gets dropped or modified.
  • Scientists need to accept all their experimental findings, no matter how they feel about them.
  • People have a tendency to hold onto old notions and ideals that have long been proven wrong due to their own stubbornness and beliefs; scientists don’t have that choice.
  • Scientists need to be experts at changing their minds and accepting change.

Theory Vs. Hypothesis:

  • In regular life, the words theory and hypothesis are more or less the same.
  • To a scientist:
    • Theory → combination of a large body of information that has well tested and verified hypotheses of certain aspects of the world.
    • Hypothesis → untested, an educated guess.
  • Scientific theories are constantly evolving.
    • The theory of the atom has undergone so many modifications and updates over the last century.
    • Chemists have refined how they view molecular bonding.
    • Biologists have refined the cell theory.

Integrity of a Scientist:

  • It’s more important to improve beliefs than to defend them.
  • Regardless of how they are outside their profession, scientists need to stay honest and true to themselves, and maintain their integrity when they’re working.
  • Scientists need to be open to accepting their own faults.
  • As Einstein said: “No amount of experiments can prove me right; a single experiment can prove me wrong.”

→ Charles Darwin hypothesized that life forms evolve from simpler to complex forms. He could’ve been proved wrong by palaeontologists finding complex life forms appearing before their simpler forms.

→ Einstein hypothesized that light is bent by gravity. He could’ve been proved wrong if starlight that was grazing the Sun and could be seen during a solar eclipse didn’t deflect.

  • The theories that get tested are widely circulated among scientists first. This way, ideas that come from wishful thinking aren’t given a platform.
  • Scientists don’t get a second chance. The penalty for fraud is public excommunication.

Speculations:

  • Hypotheses that aren’t scientific:
    • “Alignment of planets in the sky determine the best time to make decisions.”
    • “Intelligent life exists on other planets in the universe.”
  • These hypotheses aren’t scientific. They can’t be proved right or wrong. They are speculations.
  • But, saying “There is no other intelligent life in the universe,” is scientific.

Note: If a hypothesis is capable of being proved right but not wrong, it isn’t scientific.

Testing:

  • We can’t accept everyone’s ideas. Scientists accept someone’s ideas when they are testable (at least in principle.)
  • If a speculation can’t be tested, it’s unscientific.

Daily Life, Opposing Viewpoints:

  • Most concepts we live our daily life by are unscientific.
  • Most people are determined to live life by their own rules and beliefs, regardless of what science says.
  • Almost everyone has people in their lives with completely opposing viewpoints.
  • If you want to know whether your conception of something is truly right or wrong, you need to convince the opposition of its truth. If you can do that, there’s a good chance you’re in the right.
  • In theory, exposing ourselves to opposing views seems sensible. In reality, most people shield themselves from it.
  • Most “deep truths” civilizations lived by were borne of ignorance. Most things considered true weren’t. This applies today, too.

1.3

Science, Art, and Religion:

  • Science, art, and religion are three different ways of searching for order and meaning in the world.
    • Science → discovering and recording natural phenomena
    • Art → personal interpretation and creative expression
    • Religion → addressing source, purpose, and meaning
  • Science and art are comparable.
    • Art describes emotions to us, science tells us how they’re possible.
    • Science predicts possibilities, and helps us connect the things in nature around us. It broadens our perspective of nature.
    • A combined knowledge of science and art makes for a wholeness in how we view the world.
  • Science and religion have some similarities, but are mostly different.
    • Science focuses on natural order. Religion focuses on nature’s purpose.
    • Religious beliefs and practices involve worship and faith of a higher being, and the creation of human community.
    • The deeper you go, however, the more they complement one another.
    • For instance, science says light is made of waves and particles. Religion says the same. Anyone who is uninformed would think this scientific fact is untrue. They would think they have to choose between science and religion.
  • A thumb rule of science is to accept uncertainty, no matter how much you fear it. It’s okay to not know the answers, even to religious questions.
  • You need to be comfortable with not knowing.

Pseudoscience:

  • In prescientific times, we used nature against her will.
  • Science works within nature’s laws.
  • Pseudoscience → lacks evidence, has no test for wrongness, based on old ways of science.
  • Ways to view cause and effect in the universe:
    • Mysticism: applicable to religion, not science.
    • Astrology: ancient belief system, not very credible.
  • Astrology as an ancient magic is fine. When it’s put up as a science related to astronomy, it becomes a pseudoscience.
  • Pseudoscience, like science, makes predictions.
  • An example of a pseudoscience that has a zero success rate: energy multiplying machines. People invest in these machines despite the improbability, purely out of their own beliefs.

1.4

Science and Technology:

  • They’re different. Science focuses on gathering and organizing knowledge. Technology focuses on applying scientific concepts for practical purposes.
  • Technology can be used for both good and bad.
    • Case in point: Fossil fuels. They provide energy. They also endanger the environment.
    • Technology isn’t at fault for this. Humans are.
  • We do have the technology to solve a lot of environmental issues now, though. We’re using more sustainable energy sources, like solar thermal electricity generation, instead of fossil fuels. We’re recycling more.
  • Technology can lead us to a better world.

Risk Assessment:

  • Technology is accepted when its benefits outweigh its risks.
    • Eg: X-rays are used for medical diagnosis despite potentially causing cancer.
  • Risks differ based on groups.
    • Aspirins are useful for adults. In children, they can cause Reye’s syndrome.
    • Raw sewage being dumped in a local river won’t harm that town much, but it will harm the next.
  • People struggle to accept the impossibility of zero risk.
    • Airplanes can’t be completely safe.
    • Processed foods can’t be completely free of toxicity.
  • Science helps us determine the most probable options.

1.5

Physics - The Basic Science:

  • Science was once called ***natural philosophy. ***It’s the study of the living, nonliving, life sciences, and physical sciences (like geology, astronomy, chemistry, physics).
  • Physics isn’t just a part of the physical sciences, it’s a basic science.
    • It’s about things like motion, energy, the structure of atoms, and matter.
  • Chemistry is about how matter is put together, how atoms combine to form molecules, and how molecules combine to form matter.
  • Biology is about matter that’s alive.

Biology is built on chemistry, which is built on physics.

1.6

In Perspective:

  • Centuries ago, some of the most skilled artists, architects, and artisans of the world came together to construct the greatest structures we have today.
  • These works went on for centuries. They never got to see the end results. They were fuelled by something more than just worldly concerns; they did it for their faith, a vision pointing to the cosmos.
  • Most scientific and technological efforts today go towards building spaceships. The time taken isn’t even close to what these structures took.
  • Right now, we’re at the dawn of change. Earth has been our cradle and has served us well, but all cradles are outgrown one day.
  • Taking past architectural, technological, and scientific advancements as our inspiration, even today, we aim for the cosmos.