Oobleck Magic Goo
Oobleck is a cornstarch-and-water mixture that behaves differently under pressure and at rest. This guide explains setup, simple observations, and cleanup for supervised sensory play.
Age Safety Note
Do not treat cornstarch mixtures as food. Keep the mixture away from eyes and mouths, supervise closely, and skip this activity for children who mouth materials. Set up on a surface that is easy to clean.
What This Activity Offers
A cornstarch-and-water mixture may feel firmer when squeezed and flow more freely when released. An adult can model the two movements and invite observation; the mixture is not food and not every child will enjoy touching it.
Materials Needed
- Cornstarch
About 2 cups per batch. Store brand works just as well as name brand.
- Water
Start with 1 cup and add gradually until you get the right consistency.
- Large shallow container
A baking pan or dish bin works perfectly. Wide and shallow is better than deep.
- Washable apron and damp cloth
Use for clothing and surface cleanup; follow product directions.
Prep Tips (Before You Start)
- 1Mix cornstarch and water in the play container—one less dish to wash.
- 2Add water gradually while stirring. Perfect oobleck drips slowly but feels solid when pressed.
- 3If too runny, add more cornstarch. If too thick, add water drops.
- 4Set up on a stable, wipeable surface away from tubs, sinks, and walking paths.
- 5Use washable clothing or an apron and keep the mixture away from food and eating areas.
Step-by-Step Guide
- 1Let the child watch an adult mix the cornstarch and water in the stable container.
- 2An adult can press and release a small amount to show how the mixture changes its shape and flow.
- 3If the child does not mouth materials, an adult may offer brief supervised touch; otherwise keep the child observing only.
- 4Do not add toys, glitter, food, or other loose objects to the mixture.
- 5An adult ends the activity and gathers the mixture; do not leave it where the child can reach it.
- 6Dispose of the mixture in the trash; do not wash it into a drain.
Fun Variations to Try
- •Do not add glitter or other small decorative materials.
- •Use plain cornstarch and water without added colorants.
- •Do not hide toys or loose objects in the mixture.
- •Do not add fragrance or flavoring; keep the mixture away from eyes and mouths.
Cleanup Tips
- An adult gathers the mixture and puts it in the trash; do not pour it into a drain.
- Wipe the container and surface before returning the child to the area.
- Follow clothing and surface care instructions if any mixture spills.
- Discard leftovers after the activity and store ingredients out of reach.
Additional Tips
- Keep this activity for a time when the child can avoid mouthing the mixture.
- Use plain cornstarch and water; do not add food, fragrance, glitter, or small objects.
- Keep the container on a stable surface away from walking paths and water sources.
- End play if the mixture reaches the child's eyes or mouth.
References & Further Reading
General background resources for readers. They do not verify or test any specific activity, material, or setup described on this site.
Toddler Ages & Stages
American Academy of Pediatrics
What to expect physically, socially and cognitively from 1 to 3 years.
The Power of Play
American Academy of Pediatrics
An overview of play and its place in early childhood.
Choking Prevention
American Academy of Pediatrics
General guidance on choking risks and prevention for children.
Small Parts and Choking Hazard Labeling FAQs
U.S. Consumer Product Safety Commission
Explains U.S. small-parts rules and choking-hazard labels for children's products; household materials still need separate adult judgment.
Water Safety and Young Children
American Academy of Pediatrics
Guidance on close supervision around water and emptying open containers after use.
Lead in Soil
U.S. Environmental Protection Agency
Explains soil exposure during play and recommends preventing soil eating and washing exposed skin after contact.
Preventing Window Falls
U.S. Consumer Product Safety Commission
Window guards, stops, and keeping furniture away from windows can help reduce fall risks.
Art Material Safety & the AP Seal
Art & Creative Materials Institute
Explains the ACMI certification seals used on some art and creative materials.
Toddler Play & Learning
Raising Children Network
Play ideas and age-based information for caregivers.
Poison Control
America's Poison Centers
Free 24/7 guidance if your child swallows something they shouldn't.
Ready for more fun?