Catholics and Grace and Balloons

So this morning I was praying to have a way to talk to my girls about the importance of virtue and their role in acquiring it. I then thought of this metaphor/allegory for the soul, and gave this presentation to my girls this morning. It is kind of like a CGS presentation. I can give you the doctrinal content and direct and indirect aims if you are interested! Ha! Here it is, I hope it helps somebody else, too. My girls seemed to really get it! I'm pretty sure it characterizes the Catholic view of grace, salvation, and sin decently well, but of course all analogies break down at some point. I'm definitely open to feedback!

Begin with one yellow balloon (any color is fine just make sure all are the same color) that is not blown up.
"This balloon represents the soul. It is a pretty color, isn't it!"
Blow a bit of air into the balloon and then hold it shut with fingers.
"Do you see how this air enters the balloon, this is like how grace enters the soul! Who do you think gives the soul grace?"
[God!]
"Did the balloon make the air come into it?"
[No.]
"Right, but I had to open my fingers to let the air come in. This is a lot like grace: we don't do anything to make it come into our souls. God gives it as a gift. And we can grow, just like this balloon, in virtue and grace, if we open ourselves to God's gift."
Now I blow it up more (to "oohs" and "ahhs"). Quiet for a moment.

Moment #2 (same day or another)
Start with above, then begin to let out some of the air (to troubled faces).
"What happened to the air in the balloon?"
[It went out!]
"Why?"
[You opened your fingers a little.]
"Right, and our souls are kind of like that, too. God is giving us grace all of the time, and we can open ourselves to that grace, but we can also let it out. What do you think we could do that would make that happen?"
[Choose to be mean. Hit. Yell. Give angry looks. Disobey.]
"Now look at the balloon now that it is shrinking. Does it look as beautiful?"
[No.]
"It is sad to see a balloon shrink, isn't it? It is even more sad to see a soul lose grace because it doesn't make the effort to hold in the grace! This is why it is so important to try hard not to waste the gifts that God has given us through sin. These are precious gifts that make us more and more beautiful all the time, we just have to open ourselves to God's grace, and close ourselves to sin."
Now I get out a little cup.
"There are other things that we can do to make sure our soul can grow as much as God wants!"
I put the balloon in the cup and try to blow it up (it would be better if it had a lid with a straw hole through which you pull the balloon "mouth", so it wouldn't blow up at all).
"Can the balloon grow very big?"
[No, the cup is stopping it.]
"Right! Sometimes this same thing happens to us if we don't put ourselves in a place where we can grow! It can be putting ourselves in a situation where we know that we are tempted to sin, or where we don't have good examples around us."
I pull the balloon out and begin to blow it up again.
"But when we choose to put ourselves in a place where we are free to grow, and we open ourselves as much as we can, we can GROW!"
Blow it up decently big, don't tie it off.
"But, there are some things we can do that may seem to us to be small, but they are very dangerous. That is why it is so important to guard your heart and soul and keep away from things that are a danger to it."
Get a very small pin and pop the balloon.
[Gasps!]
"Do you see this pin? It seems like it isn't dangerous to the balloon because the balloon was so big and beautiful. But there are some kinds of sin that are so dangerous that they can take all of the grace out of a soul."
Hold up the mouth of the balloon, and gather the broken pieces. Try to blow it up.
"Can this balloon hold air anymore?"
[No.]
"This is what happens to a soul that destroys itself by sin. It no longer contains grace inside. This kind of sin is called "mortal sin" and there are three things that have to happen in order for the sin to be "mortal." 1: the sin has to be a grave matter--a big thing. 2: you know it is wrong and you do it anyway. 3: you freely and completely choose to do the wrong thing (no one made you do it!)"
Try to blow into the balloon again.
"Now for this poor soul, God is still there, and grace is still there. The soul can feel God's breath, and it wants to be whole again, so it begs God for forgiveness, and God can work a great miracle..."
Hide the old balloon, and bring out a new yellow balloon.
[Gasps!]
"God can make the soul whole again...."

Moment #3
Hold all three balloons, one broken, one sort of filled up but not tied off, and one tied off that is well-blown. Hold up the one that is about 1/3 full.
"Now what do I need to do to make sure that it can grow and the air stays safely inside this balloon?"
[Don't let go of the mouth and let air out. Make sure it is in a place it can grow. Keep away from dangerous things.]
"What do we need to do to make sure that our souls can grow in virtue and that we don't lose the grace we have been gifted with?"
[Don't make bad choices. Open up our hearts when God leads us to make good choices so we can grow. Don't open up to bad choices. Keep away from situations where it is harder to be good. Keep away from people when we have a hard time being good with them. Never do something we know is wrong.]
"Awesome. Now, a soul with no capacity for grace cannot enter the wedding feast in heaven, just like a balloon like this one (show the broken and yucky one) wouldn't be part of a birthday party, it would just be thrown away."
Blow up the balloon just a tiny bit and tie it off, then pull out a fully-blown & tied off balloon.
"Even the tiniest bit of air will get this balloon into the birthday party. Is it as beautiful as this one that is so full of air?"
[No.]
"This is a lot like us. We know that just a tiny bit of grace transforms us and makes us ready for heaven. When we die, we don't have to work anymore to hold on to the graces we have. Now there will only be a wonderful party--no more dangers, no more sins, but also no more opportunity to grow in virtue and grace. Just like this small balloon, not every soul cooperates with God as much as it could. Do you want to be a soul like this small, not very full balloon in heaven, or do you want to be more like this other balloon that is FULL of grace from a lifetime of working with God's grace and avoiding sin?
[THE BIG ONE!]
"Which balloon do you think will have more fun at the birthday party?"
[The Big One!]
"I think that both kinds of souls will be very happy that they are in heaven with God, but I wonder if the one that responded to the gifts that God gave to it and made choices to be holy instead of selfish, and to make hard good choices instead of easy bad ones is glad that it did.
Right now, we have the chance to grow in virtue by cooperating with God's grace and making hard decisions to hold on to those gifts, or to be lazy and let our fingers rest as the air slowly goes out of us. What do you want to do?"
[GROW!]