science tuesday :: leaves, bugs, geology and physics (or a walk in the woods)

You may think that a walk in the woods is a bit of a cop out (and you'd be right) but the sun was shining, and there is plenty of science to be found in an English woodland in autumn.


Take leaves for example. Did you know that the red and yellow pigments of autumnal leaves are always there, just overcrowded for spring and summer by the loud green of chlorophyll? It's only when the chlorophyll departs that the dazzling array of Autumnal colour becomes apparent. That said, I think we were a bit early in the season as only the blackberry leaves were starting to turn.

We bug hunt nearly every day at home - Shrek is particularly fond of creepy crawlies. In the woods today we found butterflies and ladybirds, and had the unique (and slightly stomach churning) opportunity to watch a spider suck out the juices from a fat fly. I call that observing a food chain in action - and for the first time in my life I felt sorry for a fly. This ladybird had it's work cut out avoiding the spider webs:


Geology. Wikipedia is a wonderful thing. The forest we visited today was rather special, for underfoot was a geologists dream as it overlaps into two basins which preserve Tertiary Paleogene rocks - if you want more info about what these are - this is the wikipedia link. It will tell you that this is the time when mammals are supposed to have evolved.

We also strayed into history, as the forest has been in the same family since the battle of Hastings in 1066. It also belonged to the father of Jane Seymour (wife of Henry VIII) and it was her brother who inherited the estate and became, for a time "Lord Protector" of England.

Finally, we looked at the laws of physics, where we tested Newton's Law in a rather practical fashion.

Law One:

If something is moving at a uniform speed in a straight line, it has constant velocity. At rest, it has a constant velocity of zero. Either way, an outside force must act on the object to change its velocity. The tendency of objects to continue in their constant speed straight line motion is inertia. Newton's first law is the inertial law.

If an object is at rest, it will remain at rest unless an outside force acts on it. If an object is moving, it will continue to move in a straight line at the same speed until an outside force acts on it.

Before we came along, that tree swing was just minding it's own business.

Law Two:

The force needed to accelerate an object equals the mass of the object multiplied by its acceleration, or:

Force = Mass X Acceleration.

Well, let's see, shall we?

Law Three:

For every action there is an equal and opposite reaction. (The terms action and reaction refer to forces.)


So, when the kids were pushing the swing, the swing in turn was pushing away from them. Before we got on the swing, the third law confused them...not any more.

And finally, Gravity:

There is a gravitational force acting between any two objects in the universe.

Poor Shrek learnt this the hard way when he fell and grazed his knee. Twice.

(Newton's Law info here.)