• Question: what is your favouirte science subject? (physics chemistry biology)

    Asked by jamesmolloy99 to Arlene, Colin, David, Eugene, Paul on 13 Nov 2012. This question was also asked by rilwan, phantom, emilyerin2000, ah0202, rmkearney, spacezone.
    • Photo: David McKeown

      David McKeown answered on 13 Nov 2012:

      Physics. All the cool things are physics. Lasers, Rockets … Rockets with lasers. All Physics

    • Photo: Eugene Hickey

      Eugene Hickey answered on 13 Nov 2012:

      I’ve got to say physics, being a physicist and all. But I’ve got to say that even with my meagre knowledge of biology that I find it intriguing. On the other hand I’ve never been able to get my head around chemistry.

    • Photo: Paul Higgins

      Paul Higgins answered on 13 Nov 2012:

      When I started studying science in high school I thought about doing biology, but I’m glad I settled on physics, personally. It is usually less about memorizing facts, and more about figuring things out- finding reasons for why things are they way they are. A biologist might have a reason why they think biology is better than physics…

Comments

  • James commented on :

    Cool could any of you two tell me around how many atoms are in the whole world?

    • Photo: Paul

      Paul commented on :

      Wow, great question! This is what is called a “Fermi Problem”, we have to come up with an answer by using reasonable assumptions and without being able to measure anything… I am going to assume that the earth has an average density (mass per volume) of 2 times that of water (1 gram per cm cubed, or 1×10^12 kilograms per kilometer cubed). The earth is water, rock, and has an iron core- so it is definitely more dense than water, but I am not sure by how much… The radius of the earth is about 10,000 kilometers, so (assuming the earth is a sphere) the volume of the earth is 3/4*pi*(radius cubed) which is roughly 3*10^12 kilometers cubed. Multiplying that by the density, the mass of the earth is around 3×10^24 kilograms. The mass of a hydrogen atom is about 1.6×10^27 Kg, and an iron atom is like 50 times the mass of hydrogen, so I am going half way in between to assume the earth is made up of atoms 20 times the mass of hydrogen = 20×10^-27 kilograms. So dividing the mass of the earth by the mass of an atom, we get the number of atoms! 3×10^24 / 20×10^-27 = 6×10^50 atoms in the earth… That number is huge. Anyone else estimate something different? Mine seems too large…