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Activity Objectives 

  • Students will experiment with a colloid, and learn about non-newtonian fluids.

  • Students will learn about viscosity.

Vocabulary/Literature Resource

  • Vocabulary: Colloid, viscosity, fluid, solid, liquid, non-newtonian

  • Bartholomew and the Ooblek, Dr. Seuss


Consumable supplies to gather and/or purchase:

  • Cornstarch

  • Water

  • Baggies

  • Food coloring (optional)

  • Dixie cups

Activity Plan

  • Invite students to mix cornstarch and water together in their baggies to make a thick paste (about a 1:2 ratio of water to cornstarch, but can be variable).

  • Once students have successfully created the ooblek, ask them to describe its properties: Is this a solid or a liquid? What are some things about it that act like a solid? What are some things that act like a liquid?

  • Background: Ooblek is a colloid—a suspension of solid particles in a liquid. Other notable colloids include milk, ketchup, and mayonnaise (ever notice how hard it is to get ketchup out of the bottle?). Colloids aren’t really solids or liquids—they have some properties of both. They resist flowing when pressure is applied, or when trying to be poured quickly, but if you allow the ooblek to slowly drip out of your cup or bag, it will flow!



Activity Objectives 

  • Students will learn about polymers.

  • Students will observe a chemical reaction causing a physical change.

  • Students will explore non-newtonian fluids.

Vocabulary/Literature Resource

  • Vocabulary: polymer, reaction, matter, non-newtonian


Consumable supplies to gather and/or purchase:

  • Borax

  • Glue—white, or clear PVA

  • baggies

  • disposable cups

  • food coloring   

Permantent Supplies

  • Measuring cups/spoons

  • Mixing bowls

Activity Plan

  • Invite students to help measure and mix ingredients. ½ tablespoon of Borax is dissolved in ½ cup of warm water. ¼ cup of white glue (or PVA) is mixed with ¼ cup of warm water, and a few drops of food coloring. Mix borax solution with glue solution, until slime forms.

  • Ask students to state their observations about what happens. What changes? What stays the same? What is different between the slime made with the clear glue and the slime made with the white glue? What are some other things that are slimy? Is your slime a liquid or a solid? How far can you stretch the slime?

  • Background: The glue contains PVA, a polymer. The borax acts as a cross-linker, basically taking all of the PVA molecules and sticking them together into long chains. Polymers are big long chains of molecules—they are like solids, because they can hold their shape, but like liquids, they can take on the shape of their container as well! The polymer molecules are stretchy, but can still break apart when stretched too far, or too fast. This is a non-newtonian fluid, in that it doesn’t flow evenly—if you pull quickly, it snaps, but you can pull slowly and stretch the slime very far.


Digestion in a bag

Activity Objectives 

  • Students will be exposed to the major steps of digestion

Vocabulary/Literature Resource

  • Vocabulary: Digest, Chew, Swallow, Saliva, Stomach, Acid, Intestine, Elimination

  • Adapted from ESC’s Science Assembly Program


Consumable supplies to gather and/or purchase:

  • Saltine Crackers

  • Baking Soda

  • Baggie

  • Water

  • Vinegar

  • Green Food coloring (optional)   

  • Sponge

Permantent Supplies

  • Large tooth model (optional)

  • Scissors

  • Bucket

Activity Plan

  • Invite student volunteers to assist with each step of digestion.

  • Preparation: Mix ~ 1 sleeve of crackers with ~ 4 tablespoons of baking soda. Measure ~ ¼ cup of water, 1/3 cup of vinegar mixed with 2-3 drops of food coloring.

  • Student volunteer adds cracker/baking soda mixture to baggie, and uses either large tooth, or knuckles to simulate chewing. Discuss why chewing is important.

  • Student adds water (“saliva”). Mash crackers and water to coat thoroughly. Discuss the role of saliva.

  • Discuss swallowing. Student adds vinegar (“stomach acid”). Point out bubbles, discuss chemical reactions in the stomach. Mash crackers again to coat.

  • Student adds sponge, to demonstrate intestine absorbing nutrients and water. Cover sponge with cracker mixture, to absorb water. Discuss the small and large intestines.

  • Remove sponge. Remove air from bag, and roll into a tube. Student cuts off end of bag, and squeezes cracker mixture out into bucket. Discuss elimination.

This activity can also be modified to be an individual activity, with each student getting their own sandwich-size bag of crackers, and doing each step as a group.​


Compost over time

Activity Objectives 

  • Students will observe and handle compost.

  • Students will observe how compost changes over time.

Vocabulary/Literature Resource

  • Vocabulary: Compost, decompose, bacteria.

  • Adapted from Explorit’s Nature Lab program.


Consumable supplies to gather and/or purchase:

  • Hand sanitizer

  • 3 month old compost bin

  • 12 month old compost   

Permanent Supplies

  • Trays

  • Spoons

  • Magnifiers

Activity Plan

  • Advance preparation: Create compost bins. Project Compost in Davis, CA has a variety of resources, and Explorit has sourced some compost samples from Project Compost. Check with community members, or local recycling agencies for sources as well.

  • Give each group a tray with a sample of the youngest (3 month old) compost.  Ask them to carefully examine the compost, making notes of anything they notice.  This should include the feel of the compost, the smell, the way it looks, the stuff they are finding in it (creatures and chunks – what are they?) etc. 

  • Now replace that sample with the oldest sample.  Allow students time to explore.  Throughout these explorations the educator should be moving from table to table asking questions, helping students find and identify things, and trying to get everyone to think about how the compost seems to be changing over time. 

  • Ideally the students will understand that the creatures they find (millipedes, pill bugs etc.) are beginning some of the breaking down of the compost material.  What they may not be able to note is the large number of microscopic organisms that play a much more significant role in the decomposition of organic materials into useable soil.  The combination of all these organisms create healthy, new soil.

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