Potential Energy
Potential Energy
Time for All Ages

Prop needed: An oversized pendulum. If this is hard to imagine, wrap yarn around a kickball sized ball and attach it to a long rod. Any weight suspended on a string from a stationary object can be a pendulum.

Today, I want to talk to you about SCIENCE! Who here loves science? Let’s get a big cheer for science, one of the important sources of Unitarian Universalism.

I love science too, but it’s not always easy to learn. For some people, the most difficult science to study is physics. Physics is the study of matter and energy, and some physicists study the different kinds of energy.

The two most common types of energy that I’m going to talk about today are potential energy and kinetic energy. So, let me start by asking if anyone knows what kinetic energy is?

< wait for responses. The correct answer should be something like “the energy of movement.” Repeat answers as you hear them, especially ones that are about movement.>

That’s right! It’s the energy of movement. So what, then, is potential energy?

<wait for responses. The correct answer should be something like “energy that is stored and can be used.” Repeat answers as you hear them, especially ones that are about being at rest.>

That’s right, it’s the energy that is stored up, able to be used for things like movement.  So now that we’ve talked about two important kinds of energy, there’s one big rule about energy I want to talk with you about. And it’s a big, important one. Are you ready?

Energy is never created nor destroyed. Let me repeat that – energy is never created nor destroyed. It’s one of the most important principles of physics – in fact it’s a law, called the First Law of Thermodynamics. To me, it’s one of the most spiritually meaningful rules of science.

In short, this law means that energy never goes away – it just changes form. So I want to show you how energy can change from potential to kinetic.

Let me invite my assistant <name> up to the stage. <Name> has a pendulum. A pendulum is a weight that is hanging on a string. So what do you think happens when I lift up the ball to about a third of the way?

<Wait for answers, repeating some. Then do it – wait for it to swing back and forth a couple of times before stopping it.>

Now what if I were to raise the ball up even higher? What do you think happens?

<Wait for answers, repeating some. Then do it – wait for it to swing back and forth a couple of times before stopping it.>

Look! It’s actually moving faster when it’s all the way at the bottom of the arc. The higher up I raise the ball, the faster it goes. That’s because when I raise the ball up, I’m giving it more and more potential energy. All of that potential energy changes to kinetic energy, because energy is never created nor destroyed.

Now, what happens if I don’t put any potential energy at all?  Does it move?

<Make the ball stop swinging, and leave it just hanging down.>

Noooo: It just stands still. Without that potential energy, there’s no WAY for it move.

Ok, if you want to have more fun with pendulums, check out a science classroom near you. Thanks <name>, you can take a seat.

So we’re inspired in our spiritual life by science and what we learn about science...and this is another one of those lessons.

The first lesson? We all have potential. We all have the potential to change who we are, what we believe, what we do. Because that potential energy inside of us can change into kinetic energy and move us in all sorts of different ways.

I want to focus more on this second lesson: In order for us to move, we need to charge up our potential energy. We have to recharge batteries for them to work. We have to add more logs on the fire for it to grow. We have to lift up the ball for it to swing back and forth. We have to expand our amount of potential energy to change the world, because once we run out of potential energy, we can’t keep moving. We stop. We burn out. We give up.

One of our most important tasks is to make sure we’re constantly recharging our potential energy so we don’t run out or run low. Sometimes that might mean we don’t move forward as quickly as we want, but that’s ok.  If we run out of potential energy, we’d have to stop completely.

We all have different ways we can recharge our potential energy. Some people pray. Some people meditate. Some people binge on Netflix. Some people make art. Some people find that playing with friends helps to recharge their energy. What are some ways that you like to recharge your potential energy?