Janice VanCleave Talks Science
What's the Point of Separating Food on Our Plates?
Because the human digestive system is quite complex, I will use an illustration to make it easier to understand. By taking small “bites” of information it will be easier to “digest.” (Puns intended.)
Basically our digestive system cuts, grinds, and blends the food we eat with special juices to produce a thick paste. The small intestines act like a strainer allowing the liquid nutrients to part from the solid waste. A food blender and sieve are perfect for modeling this process. All we need is food.
You can use any food and liquid but you can add a little more “meat” to this activity by first doing a bit of research on how to compost food. I am not suggesting that you build a huge compost pile. But you could, on a small scale, learn about recycling wasted food. Not all food should be part of a compost. See Home Composting Made Easy for step-by-step composting instructions as well as information about Do Compost and Don’t Compost foods.
DISCOVER FOR YOURSELF
Model the processing of food by the digestive system by putting selected food scraps in a food blender. Water or liquids need to be added to the solid food. You need enough liquid to just cover the solid food. Determine who is in charge of operating the blender. With supervision, some young children can turn the switch on and off, but you must determine this depending on the abilities of your child.
The food needs to first be mixed on slow speed, but as the food is chopped and mixed, the speed can be increased (with puree being the last step). With the machine turned off, the contents of the blender should be poured into a sieve with small holes. The object is to separate the liquid from the solid as shown.
DIGESTIVE STUDY CARDS
Be sure to add new informtion to your study cars. Most of the new information can be written on the cards that you made last week. You can also add more cards to the set with information from the investigation you did today.
ON YOUR OWN
Answer these questions about the blended food.
What part represents:
1. nutrients that would enter the bloodstream?
2. solid that will form feces which exits the anus?
3. fiber?
4. solid in rectum?
5. the separation of solid and liquid in the small intestine?
6. mixing of bolus with fluids to form chyme?
7. the opening into the digestive system, the mouth?
MARK YOUR CALENDAR
- Februrary 2 is Groundhog day. Who is Phil? How can you determine if Phil's prediction for this year is correct?
For more informtion about the digestive system, see these Janice VanCleave books:
Food and Nutrition for Every Kid
Big Book of Play and Find Out Science Projects
Have a science question you need answered? Leave a comment and our new science expert, Janice VanCleave, will come to the rescue!
Janice VanCleave is the author of fifty-two science experiment books for kids with fifteen foreign translations. Children and educators around the world use her books to explore the world of science. And now Homeschool Bliss readers can too!
Check back each Thursday for more science fun from Janice. But if you just can’t wait, visit her website Science Project Ideas for Kids (http://scienceprojectideasforkids.com/).
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