Pepper germs experiment
A fun and visual way to demonstrate how soap repels germs - using pepper and water!
This classic STEM experiment is a fantastic visual for understanding how soap helps get rid of germs. The “germs” (pepper) float on the water’s surface until you dip your finger in with soap - and then they scatter dramatically!
It’s quick, fascinating, and makes for a great conversation starter around hygiene and handwashing - especially for kids who need a little extra encouragement to scrub up.
The science: Water has something called surface tension, which allows the pepper to sit on top. When you add soap, it breaks that surface tension and causes the water molecules to pull away from the soap - taking the floating pepper (aka “germs”) with it. It’s a simple but powerful way to show how soap chases away germs.
Materials
Prep / make
Step 1:
Fill a shallow dish with water.
Step 2:
Sprinkle a layer of black pepper on the surface.
Play
Step 1:
Invite your child to look closely at the water and pepper.
Step 2:
Ask what they think will happen if they touch it.
Step 3:
Dip a finger or cotton bud in soap and then gently touch the water’s surface.
Step 4:
Watch the pepper (aka “germs”) shoot away from the soap!
Extend
Use glitter instead: Swap pepper for glitter to make the visual even more sparkly and dramatic.
Role-play handwashing: Do the experiment before heading to the sink and then model proper handwashing together.
Link to real life: Talk about how germs aren’t visible like pepper, but soap still makes them go away!
