Sin Can Change You – Liquid Nitrogen | Object Lesson
This is an object lesson that can help you teach your class about how sin can change you! It make your heart hard and you don’t respond to life’s challenges the same way!
Needed:
- Liquid nitrogen (available at welding supply stores or online)
- A Dewar flask or insulated thermos for handling liquid nitrogen
- Thick gloves and safety goggles
- A metal or glass bowl
- Fresh flowers (roses work best)
- A rubber bouncy ball (racket ball or similar)
- Hammer
- Tongs
- Safety mat or tray for demonstration
This lesson is a powerful visual about what sin can do to a tender heart. Before teaching it, make sure to review all safety precautions. Liquid nitrogen is extremely cold (around -320°F) and should never be handled by children. Always wear gloves and eye protection, and practice the steps ahead of time.
Begin by explaining to the children that this experiment involves something very cold—so cold that it can freeze nearly anything it touches. Ask the group what the coldest thing they’ve ever felt is, and let them give a few answers. Then reveal the container and tell them that liquid nitrogen is hundreds of degrees below zero—far colder than ice. Explain that because it’s so cold, it can change ordinary things into something completely different.
Pour a small amount of liquid nitrogen into the bowl. The vapor clouds that form will instantly capture the kids’ attention. Tell them that in today’s illustration, the liquid nitrogen will represent sin. Just like sin, it may look interesting or harmless at first, but once it gets close, it begins to change everything it touches.
Hold up a fresh flower and have the children describe it—soft, colorful, alive, and beautiful. Tell them this flower represents a heart that loves God. Gently place the flower into the bowl of liquid nitrogen using tongs. They’ll hear sizzling and see the vapor swirling around it. After a few seconds, remove the flower and show that it still looks normal. Explain that sometimes people think they can be around sin without it affecting them, but something inside has already started to change.
Dip the flower into the nitrogen again for a few more seconds. Then lift it out and ask the kids what they think will happen if you squeeze it. Carefully crush it between your fingers or tap it against the table—it will shatter into pieces like glass. Let the children react, then explain: “This is what happens when sin hardens a heart. What was once soft and full of life becomes cold, fragile, and easily broken.”
Next, bring out a rubber bouncy ball. Drop it a few times to show how it normally bounces back, just like someone who is living close to God—when trouble comes, they can bounce back because they’re strong in their faith. Then place the ball in the liquid nitrogen for about 30 seconds. Pull it out with tongs, and drop it again. Instead of bouncing, it will shatter into pieces. Explain that when we stop praying, stop obeying God, and let sin take over, we lose that resilience. What once could bounce back under pressure now breaks apart.
Wrap up by emphasizing that sin makes hearts cold and fragile, but God can restore and warm them again through repentance. Tell the children that no matter how cold or broken someone’s heart becomes, Jesus can make it soft and alive again.
Close the object lesson by saying:
“When we stay close to God—reading our Bible, praying, and obeying His Word—our hearts stay warm and full of life. But when we let sin creep in, we become cold and breakable. Only God’s love can thaw a frozen heart.”
