Soap and Pepper
I’ve been wanting to post this up but didn’t have the time till today (Thursday) to take the pictures. But I’m backdating this to Wednesday anyway just cos I’m particular that way…. 😛
So here it is. With thoughts about washing and soap fresh in our minds from Bookmark Monday, I wanted to share this simple little experiment and Bible object lesson that you could easily try at home. Here is how it goes:-
You will need: Paper, marker pen, cellophane tape, a toothpick, a clear plastic container or glass bowl, water, pepper, dishwashing liquid.
1. Cut a piece of paper and label it “God’s Word”. Tape it to the bottom of the container.
2. Fill the container with water. This is a picture of a believer who hears God’s Word and puts aside all filthiness. You can see “God’s Word” clearly.
3. Now shake some pepper into the container. The pepper represents our sinful wickedness and filthiness, such as the times when we fight with our siblings, don’t watch our words or deeds, etc. “God’s Word” is now clouded over by the pepper.
Try picking up the pepper with the toothpick. Does it work? This shows what it’s like when we do things our way.
4. Now dip the tip of the toothpick into the dishwashing liquid. Stick the tip into the middle of the water and see what happens.
🙂 When we put aside all filthiness, we can clearly see God’s Word.
**Sourced from “Boy, Have I Got Problems!” Discover 4 Yourself Inductive Bible Studies for Kids – James, by Kay Arthur and Anna Arndt.**
Why does the dishwashing liquid repel the pepper?
The pepper in this experiment helps to make the surface motion visible. It does not in itself contribute to the repelling motion. The motion results from the reduction in the water’s surface tension when the dishwashing liquid is added.
Surface tension is the result of the strong attraction between molecules in a liquid. Water has an unusually high surface tension compared with most other liquids because water molecules are very strongly attracted to each other. This strong attraction allows you to slightly overfill a glass with water, and allows some insects like the water strider to walk on its surface.
Dishwashing liquid is a member of a chemical family known as surfactants (short for surface active agents). Every soap molecule has two distinct ends called the head and the tail. The tail strongly repels water while the head is strongly attracted to it.
When you first add the dishwashing liquid to water, the molecules scurry across the surface with their heads down and tails sticking up. Once the surface is full, the remaining soap molecules begin forming small droplets called micelles by joining their tails.
Dishwashing liquid heads are attracted to water, but not nearly as strongly as water molecules are attracted to each other. This is the reason why the dishwashing liquid reduces the surface tension of water. Water molecules on the surface pull away from where you add dishwashing liquid.