Mai Lesson

Keeping the Harvest

Science · 30 min · Any age · You and your child together

This Spark challenges families to discover how people kept food long before refrigerators. Through a simple experiment with cucumber and apple slices, learners explore the science behind drying and salting and see how they stop food from spoiling. You set up the experiment today, then come back on day 3 for a 5-minute check-in to see what changed.

What your child gets out of it

• Identify traditional food preservation methods like drying and salting.
• Explain how removing water prevents food from spoiling.
• Observe and record changes in food samples over time and draw conclusions.

What you need

• Cucumber (or Zucchini, Carrot)
• Apple — Bananas will brown quickly, but still work for drying comparison. (or Pear, Banana)
• Salt — Table salt works best for this experiment.
• Small plates — You'll need three small plates. (or Bowls, Wax paper)
• Paper towels — For drying the apple and absorbing moisture. (or Clean cloth, Coffee filters)
• Small zip-top bags — One to seal an apple ring in, and spares for throwing away any sample that goes fuzzy. (or Sandwich bag with a twist tie, Small lidded container)
• Knife — A grown-up does the slicing.
• Pen or Pencil
• Experiment Log (worksheet or paper) — You'll need to draw a simple grid if not using the printable. (or Plain paper and ruler)

How it runs

1. Introduction: The Winter Challenge · 5 min
2. Explore & Plan: Our Food Preservation Test · 8 min
3. Discussion: The Science of Spoilage · 6 min
4. Activity: Setting Up Our Experiment · 9 min
5. Summary: The Harvest's Secrets Revealed · 2 min