Category: Engineering

How to make a magnetic marble run for your refrigerator door. Fun STEM (or STEAM) activity for kids!

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Suitable for

You can adapt this activity to suit preschoolers, kindergarteners or young school-aged kids. My daughters Jewel and Bumble Bee were 6 and 4 years old when we first made this.

We made this fridge-door marble run ages ago, but I’m only just getting a chance to share it now, because, you know, kids and life and stuff…

It was lots of fun, and super simple to make.

How to make a Fridge-Door Marble Run

We used:

Fridge door marble run!

Of course, you could make this with plain cardboard rolls, but decorating them with washi tape is fun, and much prettier!

I used a hot glue gun to stick magnets onto the side of our tubes (mainly because the results are quick, and I’m impatient!). You could also use regular PVA craft glue, and just wait overnight for it to dry. If you use self-adhesive magnets, you may have to add extra glue between the cardboard tube and the magnet so they stick ‘properly’.

Stronger magnets are best, especially if you plan to use heavier balls, like marbles or steel balls, as they have more force behind them. If you’re only planning on using pompoms, then you could get away with weaker magnets (like the promotional ones you sometimes get in your letter box).

Decorate toilet paper rolls with washi tape & stick on magnets to create a magnetic marble run for the fridge door.

My daughters (Bumble Bee, 4.5 years old and Jewel, almost 7 years old) helped decorate a few of our cardboard tubes, and I finished the rest. Stripes are easy and look great!

Testing out the marble run

We created some shape variations by cutting an angle in the end of some of the cylinders, or by cutting a small section out of the side of another. (These variations are great to have later, when the kids are trying out different marble run designs.)

Creating magnetic marble run piecesOnce you’re done creating and decorating your tubes, pop them on the fridge, and wait for the kids to come and play! (I *might* have played with them a wee bit too. It’s fun!)

Magnetic marble run for your fridge door - fun science for kids

Make a magnetic marble run

Some questions to ponder:

  • How many zig zags can you incorporate into your design?
  • Use a stopwatch to time your marble run. Can you modify your track to make it quicker? Slower?
  • Test your marble run using a heavier smooth ball (eg a marble) vs a lighter rough ball (eg a pom pom). Do you need to modify your design to suit the ball type? How does the type of ball affect the speed?
  • How far does your ball roll when it comes out of the end of marble run? Can you modify your design to get the ball to land in a particular spot?

Make a colourful DIY magnetic marble run

Fun Science

There’s a number of factors that influence your marble run design.

The first is gravity. Gravity is the force that pulls objects downwards (towards the centre of the earth). It’s what causes the marble to roll downwards.

The second is energy (and conservation of energy). The faster an object is moving, the more energy it possesses. When objects collide, energy can be transferred from one object to another, changing their motion. When a ball hits a zigzag in the marble run, the energy is transferred from the ball to the marble run wall, and then back into the ball, causing the ball to change direction.

The third is force (and the relationship between energy and force). The faster and heavier an object, the more force it will have. Heavier balls will require a slower track (or stronger magnets), else the force of the ball will push the track out.

The fourth is friction. Friction occurs when two objects rub against each other (slowing movement and creating heat in the process). The texture of the ball and/or the track will affect the friction.

Make a DIY magnetic marble run for the fridge using toilet paper rolls and washi tape!

Science isn’t the only subject that can be introduced here. You could easily turn this into a playful STEM or STEAM (STEM + art) activity:

  • Science – see above! Marble runs are a classic physics activity covering gravity, energy, force and friction.
  • Technology – You could use a digital stop watch to time the marble run.
  • Engineering – taking in the various forces into account, testing and making design modifications are all classic engineering activities.
  • Math – estimating, measuring and comparing times is all great maths practice. Likewise, estimating, measuring and comparing how far the marble will roll. You could record results in a table.
  • + Art – decorating your tubes! We used washi tape, but you could also paint the cardboard tubes or draw patterns using markers…

Make a DIY magnetic marble run - for your fridge door!

For more physics fun, check out our Physics Experiments for Kids archives, including:

Make a magnetic marble run for the fridge door - STEAM activity for kids

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Did you see this tall Magna-Tile tower we built yesterday?

Using magnatiles to measure DIY catapult projectile heights - fun STEM activity for kids combining science, engineering and maths with playWe built it to measure how high our catapults were shooting. We had to keep building it higher and higher, as we discovered one of our catapults had a very high trajectory!

All that tall-tower-making had me thinking…. If we built it just a little bit taller, could we use it to measure the girls’ heights?

So that’s what we did!

Measuring height with Magna-Tiles is a fun way to explore math and measurement at home

Suitable for

This is a fun activity for 3-6 year olds. Using everyday items that are a uniform size to measure objects and compare their relative size is one of the maths skills Jewel learned when she was in kindergarten and Year One.

Bumble Bee and Jewel were 4 & 6.5 years old here.

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The girls have been lucky enough to receive two Magna-Tiles sets (this 100 piece one and this 48 piece one) over the past few years as Christmas gifts (thanks Grandma!), and so are quite familiar with building with them. Even so we had to get a little creative in working out how to build a tower tall enough to measure Jewel, stable enough that it wouldn’t fall down, using only the limited number of square tiles that we had available.

Here’s what the structure looked like from behind.

The rear of the tower

We ran out of squares at the very top, so we made our own using right-angled triangles. (Hands-on geometry!)

We found out that Bumble Bee is currently 13 Magna-Tile squares tall, and Jewel is currently 16 Magna-Tile squares tall, meaning that Jewel is 3 Magna-Tiles taller than Bumble. (Oh, don’t they grow up so quickly!)

Measuring the height of kids with a Magna-Tiles tower is a fun way to practise math at home.

The engineering and math components make this a fun STEM activity that kids can try at school or home!


For more Magna-Tiles fun, you might like:


You might also like to follow our Go Science Kids, STEM for Girls and Playful Maths for Kids boards on Pinterest.


And, of course, you can always subscribe to our newsletter, to receive all our latest activities via email. We’d love to have you join us!


* This post contains affiliate link(s). An affiliate link means I may earn a referral fee or commission if you make a purchase through my link, without any extra cost to you. I was not obligated to link to any particular product, and all opinions are my (or my kids’) own. Thank you for your support.

How to make (and test) DIY craft stick catapults! Fun catapult STEM project for kids, that combines physics, engineering and math with play.

Catapult STEM - how to make DIY craft stick catapults

Making catapults is one of those classic STEM activities that are so much fun.

Y’all know what a STEM activity is, right? STEM stands for Science, Technology, Engineering and Math, and a great STEM activity is one that incorporates two or more of these pillar subjects, in an open-ended, lets-find-out, hands-on kinda way.

Making catapults involves three of the four pillar STEM subjects – there’s the whole projectile, forces, physics thing (Science = tick!), creating a machine and evaluating different designs (Engineering = tick!) and measuring the height and distance of your projectiles (Maths = tick!).

So I’m pleased to present this as the C is for Catapult submission in this year’s A-Z of STEM Activities for Kids series that Little Bins for Little Hands is running. (We also submitted a Why STEM for Girls is So Important post to that series too – because that’s something that we tend to be a bit passionate about around here!)

Anyway, I digress.

We’ve made easy upcycled catapults before (which were so much fun!). But this time, I thought we’d try making classic craft stick catapults – mostly because I’ve been wanting to make some for ages and ages and ages.

Launching a DIY craft stick catapult
Read More C is for Catapult!

How we made our first DIY loungeroom pulley – and learning about physics and simple machines through play.

Make a DIY Loungeroom Pulley - for physics science fun and learning through play

We’ve been wanting to make a pulley for a while now.

I’m not quite sure when exactly the fascination started, but it’s been going for a few months at least. Every time my daughter Jewel asked if we could make one, I couldn’t help but think “Yes, we should to get onto that. We’ll need to look up what to do, and make a trip to the hardware store to gather some supplies, including one of those fancy pulley wheel thingies. But right now we have abc and xyz going on. So we’ll look into it later. Soon…

To be honest, I’d turned it into something that felt a bit daunting.

I’m not necessarily afraid of daunting. But with other things creating busy-ness in our lives, daunting made it easy to keep putting our pulley off until some fictional future time when we’d have plenty of time to research, plan and gather supplies.

But then I realised… it really doesn’t have to be that complicated. By definition, pulleys are a simple machine, after all! Read More DIY Pulley for the loungeroom stairs

Magnatiles for Christmas present

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The girls were lucky enough to receive this set of Magna-Tiles from their Grandma for Christmas. They play with them almost every day. There are so many ways to play with Magna-Tiles, and we’re only just scratching the surface. But I thought I would share some of my initial reflections on how they’ve been playing with them so far, and in particular, the rich hands-on geometry that has evolved out of this play.

Usually when the girls play with their Magna-Tiles, they construct some sort of prop for imaginative play. They build trains, rockets, castles, stables, ships, school rooms and dungeons. Because the Magna-Tiles connect together really easily, they can build these structures in a few minutes, and they continue to adapt their structures (by adding or taking away pieces) as they play, so that their building is always evolving. Read More Hands-on Geometry with Magna-Tiles

STEM Challenge. Building 3D structures.

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We’re joining in again for the second week of the 28 Days of Hands-On STEM Activities for Kids, and this week’s theme is STEM Challenges! (In case you missed it, last week’s theme was STEM Goes Green and we made this upcycled catapult.)

This is our first try at doing a ‘stem challenge’. I wanted to come up with an idea that would be age appropriate for my five and a half year old daughter Jewel, as I was worried that something too difficult would drain her awesome enthusiasm-for-all-things-science that she has going at the moment. After a lot of thought (and a little bit of inspiration from Jamie’s kid-made abacus), the STEM challenge I decided to give Jewel was: can she build a 3D structure of her choice, using just straws and pipe-cleaners (and scissors, to cut the straws and pipe-cleaners to length, if required).

The first thing Jewel asked was, “What’s STEM?” Read More STEM Challenge: Can you build a 3D structure?