Lesson Report - OT - Exodus 24

This year we're studying the Old Testament, and today's lesson was on Exodus 24, the story of Moses and the Israelites gathered on Mount Sinai, shortly after Moses has received the Ten Commandments. The Come Follow Me lesson plan is here in case you're interested, although I ended up doing something a little different here. The theme for my lesson was blood filtration, and the kids had a blast with the central science experiment. 

Red blood cells. Photo by ANIRUDH on Unsplash.

The idea for this lesson came from a section early on in Exodus 24:

The text describes something called a "blood covenant", where animal sacrifices were given to Heavenly Father. Following the ceremony, blood from the animal would be scattered upon the altar and the worshippers in order to spiritually cleanse their sins. Fortunately today our services involve the sacrament as a means of spiritual renewal, by partaking of the blood and flesh of Christ through drinking water and eating bread. I think it's fair to say that the contemporary approach is somewhat more palatable, not to mention laundry friendly.

Blood performs many important roles in keeping animals alive, one of which is to remove waste products from our cells from the body. Our cells are constantly using molecules derived from our food, combined with oxygen, to create enough energy to run our bodies. In the process, they will create unwanted side products which need to be removed to avoid any toxic effects. One such product is creatinine, which is created by the breakdown of our muscle cells. This molecule escapes from our cells and enters the blood stream. Our circulatory system, the network of vessels (tubes) that carry blood around our body, then takes the unwanted substances to the kidneys, which are responsible for filtering them out from the blood and removing them (through urine) from the body.

During the lesson, we built a simple model of the kidney and used it to filter impurities from blood. The approach we took is similar to the method described here. 

• I had one child squirt some tomato ketchup into a bowl, add water to it, and make it runny. This is the blood.
• Another child tore open a milkshake straw and added the contents to the blood mix. This is the impurity. Anything insoluble will do here. (Sand or grit is fine but we had these straws lying around so I figured I'd use these.)
• A third child took a tea towel, and tied it over a transparent plastic cup with a rubber band.
• Finally, we poured the impure blood mix onto the top of the tea towel, and watched as the red ketchup liquid passed through into the cup, leaving the impurities in the tea towel.

It worked a treat! Once we'd finished this, we read the verses above and talked through what the blood covenant meant, and how that was an early form of the sacrament. Finally we discussed how we administer the sacrament today, and what it means to us. 

As a bonus, I added a little word puzzle at the end. I asked one child to write the first letter of each word from Exodus 24 verse 8, from "And" to "people", and told them that there was a secret word hidden in this. They had to guess a 7 letter word using these letters. I let them guess one letter at a time initially, "hangman" style, and after a few letters, they had to guess the word.

The letters are A M T T B A S I O T H P, and the word they have to guess is Baptism. Which fits in nicely, since baptism is a form of using water to perform spiritual cleansing too.