Scientific embarrassment

I'm listening to a Ted talk by a chap who says we don't always know what we think we know. To prove it he says, he asks 4 questions of science educators, producers of science TV shows and even of 7 year old children.

I've stopped the video of his talk at 1:55m where the 4 questions are displayed and I'm going to try my hand at answering them. I'm not going to refer to Google, or the internet in anyway - I'm going to draw purely on what I already know (or think I know).

If you want to follow along - stop reading here, click the link above and prepare your own answers to the "Science Pop Quiz" and see how you do.

Don't scroll down if you are following along!

Really!

Ok...

So here goes:

1. A little seed weighs next to nothing but a tree weighs a lot. From where does the tree get the stuff that makes up a wooden desk?

My answer: from the air. Specifically the tree-stuff is mostly cellulose and that is a complex molecule which the tree gets by binding carbon from CO2 in the atmosphere using photosynthesis. The tree knows how to do this due to the genetic codes stored in the seed.

2. Can you light a little torch-bulb with a battery, a bulb and one piece of wire?

My answer: you can. You touch one pole of the battery to the terminal on the base of the bulb, and use the wire to connect the other pole of the battery to the conductive housing of the bulb. This question seems to talk about 2 bulbs - if that is not a mistake, then you might be able to connect them in series by touching the terminal to the housing.

3. Why is it hotter in summer than in winter?

My answer: Because the axis of rotation of the earth is tilted with respect to the plane of its orbit around the sun. In the height of the southern hemisphere summer, the south pole is partly pointed toward the sun by this tilt, exposing a lot more of the earths southern aspect to the sun for longer.

4. Could you scribble a plan diagram of the solar system showing the shape of the planet's orbits?

My answer: Hmm tough one. I drew elliptical orbits with the planets around the sun, starting from Mercury (closest), then Mars, Venus, Earth, Jupiter, Saturn, Uranus, Neptune and Pluto (furthest away). I don't think the elliptical orbits all lie in the same plane.

How sure am I about my answers?

I'm most unsure about the planets one, but I think I probably got it about 80% right.

Ok. Now to click "Publish" and embarrass myself, by playing the rest of the video and seeing how I did.