“Slug” Races | Why do Slugs Have Slime?

I can’t believe I am about to say this, but here it goes anyways… we love slugs. Yep. You read that right! We have been fully immersed in a slug project for the last week and we have been learning more about slugs than I ever thought we could. We have been using the project based approach to guide us in our studies. One burning question so far has been “Why do slugs have slime?” This is how we investigated that question and what we learned.

Slug Races to Explore Slug Slime and How they Move

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Ever since Bones (7) found slugs in the garden last week, we have been caught up in a full swing slug study. I have to admit, this wasn’t the first exploration we did with the slugs and it definitely wasn’t the last. However, as part of the STEAM Summer Science Series, we thought this was a great fit for STEAM activities that focus on the sense of touch. Be sure to check back tomorrow to see what we learned when we raced real slugs!

Why Do Slugs Have Slime

After we learned about how slugs move (remember to check back for that information), the boys were fascinated by the slime trail the slugs left behind and how the slugs could climb upside down. As we do with all of our projects, we write down and draw our observations and then we come up with questions we need answers to.

Slug Slime Trail

We learned that slugs could not move at all if it weren’t for the slime they excrete from the bottom of their body. In fact, it is this mucus that allows them to move as well as stick to the surface they are on. Slugs and snails both secrete this same mucus.

The most interesting thing that we learned about this mucus is that it is actually a liquid substance that changes form. When it is first secreted it is liquid which allows the slug to move, however when the slug stops moving the substance turns into a more solid state.

The boys immediately thought of oobleck and some of the other substances that have similar viscosity. They were so interested in fact, that they decided they wanted to set up their own investigation to see if they could recreate a substance close to slug slime.

(Note: This experiment was entirely designed by children. I simply assisted them in executing their plan.)

Why Do Slugs Have Slime Investigations

Mock Slug Races

Setting up the Experiment


Olive Oil

Gummy Worms

Fork (to Mix)
Lid or Cardboard for Racetrack

making fake slug slimeSet Up:

Making Fake Slugs

In separate bowls mix water with the mayonaise and jelly until the substance is a slime like consistancy. The boys mixed until they felt it looked and felt like what they thought slug slime should feel like. Then, place several “slugs” into the mixtures and coat them well. While the boys mixed, they predicted the Mayonaise slime would make the best slime and help the slugs win the race.

Conducting the Experiment

Slug Race Track

Now that their slugs were super coated, they were ready to test. They were initially worried about “releasing” all three at the same time, however, the slug with the oil slime didn’t move at all, so they were left to test the other two.

They conducted the races several times to see what the results would be after repeated trials. The results and observations they made were fascinating.


Making Observations and Noticing

slug slime races

I could tell you who won, but what fun would that be? Honestly, I think you and your kids should get all messy and try this awesome sensory science experiment. Who do you think would win? What do you think is different about the slime? Could you make a better slug slime?

If you want to add in just a little more fun and learning. You can print off this simple recording sheet for your races. Your kids will have a blast timing the slugs and testing the variables over an over.

Summer STEAM Camp

Be sure to stop by the rest of the posts in the Summer STEAM Camp series! This week everyone is focusing on the sense of “touch”. 

Easy and Colorful Magnetic sculpture | Pink Stripey Socks
Encourage Your Inventor with Creative Pool Noodle STEAM Fun | One Time Through
String and Bead Puzzle | What We Do All Day
4 Engineering Challenges for Kids with Craft Sticks, Cups, and Cubes | Frugal Home 4 Boys

How to Make a Travel Geoboard
Bath Bomb Science
Gelatin Art

More Adventures in Learning

Top Summer Enginneering Projects for Kids

Travel Kit for Little Engineers


Discover how to get siblings to get along even when all they do is annoy each other with the Sibling “Get Along” Poster Pack!

10 thoughts on ““Slug” Races | Why do Slugs Have Slime?”

  1. Pingback: 4 Engineering Challenges for Kids (Cups, Craft Sticks, and Cubes!) - Frugal Fun For Boys

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  3. This is so, so cool! I love how the investigation was kid-driven! What great ideas! Pinned!

  4. Pingback: STEAM Camp: How to Make a CD Case Travel Geoboard - Left Brain Craft Brain

  5. Pingback: Encourage Your Inventor with Creative Pool Noodle STEAM Fun - One Time Through

  6. Such a neat idea – your boys are obviously future scientists in the making! I’m actually inspired to go on a slug hunt with my son in our backyard now!

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  8. Pingback: Sensing STEAM: 30+ Awesome Science, Technology, Engineering, Art and Math Activities for Kids - Left Brain Craft Brain

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