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Monday, April 6, 2015

Why Science is Better Than Religion: Gravity and Torque and the Egg Carton Problem

Let me propose a real life practical example, very mundane but useful, that applies science to help with a real practical day to day life problem.

If anyone has picked up eggs and dropped them, then this will explain why.

Exhibit A:



I have dropped egg containers because they were weighted to one side and I didn't know it.

The problem is that with a hidden distribution of eggs inside the container, sometimes people take too many eggs from one side and that makes the inertial moment of the container off-balance or off centre.  When you pick it up, and didn't look inside first (who looks in the container first?) that can be a problem.  I don't look. You may experience an extreme inertial moment - or torque for simplicity - based on the distribution.

Let me explain as best I can with kitchen-sink physics:


Hold a mop or broom like this:



Feel the pull of gravity.  Now hold it like this:


Notice the difference in how much muscle strength you need? It will be lighter up and down rather than horizontal.  This is because when the broom geometry ( mass distribution geometry for you smarties out there) is near your hand it has a lower inertial moment therefore the torque force is less - put simply - to resist it falling than when the mass of the broom is spread out over distance along the broom centre axis when you hold the broom out horizontal.

The wider the weight distribution, the greater the torque you need to apply to stop the broom from falling. Your hand is zero point.  Simple?

Here's the equation of the inertial moment with respect to some zero location:


I = \int_m r^2 \mathrm dm

This is why torque is so much more powerful than a translation force of the same size. Torque is force-multiplied by distance (oversimplistically for those that know more). In the case of gravity acting on the broom weight away from zero:  mass * gravity * distance.  Torque is how car engines drive you and generators work. Torque rather than just force.  Inertial moment I varies as the integrated square of distance from the zero.  If that is gibberish then just please trust your experience with the broom. You experienced the difference your muscles needed to apply counter torque yet the weight of the broom did not change. Just the distribution did. The weight was farther away from zero.  This equation explains why the broom is heavier when the weight (gravity times force) is farther from zero. Your hand is zero point. You can only apply forces where your hand is.

It all can be explained with torque and gravity.  The counter torque needed is less if the weight is closer to the zero.

Now back to the egg container.  You don't know without looking where the eggs are. So when you pick it up from the "wrong side" it may be heavier than you expect and you might drop it.

If you pick up the eggs and they are distributed like this:


then the inertial moment from your hand zero (my poorly drawn hand is bottom left) will be smaller than if you pick up the eggs like this:


So if you don't want a surprise from the egg distribution then one way is to keep the mass at the centre of the container.  To do that, take the eggs out from the container from the outside varying left and right like this:



This will make it more likely you pick it up without a huge change in the inertia of the egg distribution and therefore it may be less likely you drop the eggs.  I call this the Erickson egg selection distribution but you can use it free of charge. You're welcome!

The point is, science is knowing about the universe the way it is. We all learn from dropping things.  When we understand how things work, we can apply it to things that mankind does to help everyone out.  If this blog saves one egg from the floor, then science has helped.

Can religion help you even in small little ways like science can?

Again for those out there that don't get the point of this blog post, name one religious book reference, chapter or verse, that explains gravity and inertial moment so as to help people with this problem.