5. Slimy cells - Logistics

20-25 min introduction and make PVA slime
30-45 min assemble cell models
10-15 min create cell model keys
20 min discuss the metric system of measurement and use ratios to calculate the relative size of a person made of ziplock bag sized cells


Each student needs a copy of the Slimy Cell Models handout.

For enough PVA slime for a class of 30 students:

  • 240 g PVA (order from Flinn Scientific catalog # P0154, $19 for 500 g)
  • 75 g Borax (Sodium Tetraborate Decahydrate (Na2B4O7*10H2O), marketed as a “laundry booster” and found in most grocery stores and pharmacies among the laundry detergents for around $10 for a lifetime supply, 76 oz box)
  • water
  • several colors of food coloring
  • 30 ziplock sandwich bags
  • 9-12 empty water bottles with pop-top lids
  • 3-4 empty two liter soda bottles
  • 8-10 100 ml graduated cylinders
  • 8-10 50 ml beakers with gradations on the side
  • 3-4 trays or plastic bins for placing materials for making slime
  • large pot and stove (PVA requires heat to fully dissolve in water)

For cell walls, gather as many pint-sized strawberry baskets as you can – two baskets, one inverted over the other, readily enclose a filled ziplock bag, demonstrate the structural support provided by the cell wall, and illustrate the permeability of the cell wall.

For organelles, assemble a wide assortment of small, inexpensive items that students can select from. It is best to avoid food items like beans and candy since they will decompose and grow mold inside slime, creating a disgusting mess. An alternative is for students to bring objects from home for their models. Some items you may want to consider include:

  • large confetti
  • pony beads
  • pom-pom balls
  • wooden beads
  • Styrofoam peanuts
  • paper clips
  • tin foil
  • saran wrap
  • bubble wrap
  • aquarium gravel
  • plastic drinking straws
  • aquarium tubing
  • yarn
  • ribbon
  • Christmas tinsel
  • plastic Easter eggs