7 STEM Activities for Toddlers Ages 18-36 Months

If you've ever watched a toddler drop the same thing off the couch twelve times, knock over a tower they just built, or keep pouring water back and forth long after you thought the activity was over, you've already seen the basic instinct these ideas use.

At 18 to 36 months, STEM can be very ordinary. Your child changes one thing, watches what happens, and usually wants to do it again immediately. A higher ramp, a softer landing spot, a wetter sponge, or a different paper shape is plenty to give them something new to notice.

These activities keep the materials big and the result easy to see, which makes them much easier to use with a toddler who'd rather touch the experiment than listen to you explain it. Stay close around water, ramps, and moving objects, and let the repetition happen if they're still into it.

1. Cup Tower Crash Test

Give your toddler several large lightweight plastic cups. Stack two or three together, then let your child add another cup or knock the tower down. Rebuild it with a wider bottom, a narrower bottom, or a taller stack and see what changes when they push it again.

Toddlers rarely need encouragement to knock the tower down, so use that part instead of fighting it. Let them decide when the tower is tall enough, give it a push, and then build a different version together. If they start making their own ridiculous stacks, stay with that and see which ones survive the first tap.

Why it works: Every cup changes the tower's height and balance, and the crash gives immediate feedback about which stack was easier to tip.

Age range tweak:

• 18-24 months: Build most of the tower and let them add one cup or knock it down.
• 24-36 months: Let them build short towers themselves and compare wide and narrow bases.

2. Book Ramp Ball Roll

Prop one large board book or sturdy tray on a low cushion to make a gentle ramp. Use one large soft ball that's far too big to fit in your toddler's mouth. Release it from the top, then lower or raise the ramp slightly and roll it again.

Once they know the ball is going to roll, move the basket or put a piece of painter's tape where the ball stopped. That gives them something visible to compare without a lot of explaining. If your toddler keeps changing the ramp themselves, help stabilize it and let them see what their new setup does.

Why it works: Changing the ramp height changes how quickly the ball moves and how far it travels after reaching the bottom.

Age range tweak:

• 18-24 months: Use one low ramp and help place the ball at the top.
• 24-36 months: Try two ramp heights and let them release the ball themselves.

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3. Sponge Squeeze Transfer

Put a small amount of water in one wide bowl and set an empty bowl beside it on a towel. Give your toddler one large kitchen sponge. Let them press the sponge into the water, lift it to the empty bowl, and squeeze. Keep repeating until the first bowl has less water.

The repetition is the activity here, which is helpful because toddlers usually love the squeeze more than the idea of 'moving water.' Let them keep going until one bowl is noticeably fuller, then swap the bowls and start over. A towel underneath will save you from having to care about every spill.

Why it works: The sponge absorbs water when compressed and released, then gives that water back when the child squeezes it over the second bowl.

Age range tweak:

• 18-24 months: Use only a shallow amount of water and help move the sponge between bowls.
• 24-36 months: Let them repeat the transfer and notice which bowl is getting fuller.

4. Flat-or-Crumpled Paper Drop

Use two full sheets of lightweight paper. Leave one flat and loosely crumple the other into a large ball. Hold both at the same height and drop them together. Let your child pick them up, open the crumpled sheet a little, or crumple it tighter and repeat.

Do the first drop together so your child can see both pieces fall at the same time. After that, let them be the person who crumples, opens, and drops the paper, even if the shapes get increasingly weird. The comparison gets more interesting when they feel like they made the version that changed.

Why it works: The two papers have the same material but different shapes, so they move through the air differently as they fall.

Age range tweak:

• 18-24 months: Do the first drop for them and let them chase and return the papers.
• 24-36 months: Let them change the crumpled shape and help release both pieces together.

5. Ball Bounce Surface Test

Use one large soft rubber ball that's far too big to fit in a toddler's mouth. Drop it from a low height onto a hard floor, then from the same height onto a rug or folded blanket. Let your child retrieve the ball and repeat.

A toddler will usually turn this into a chase game after about two drops, which is fine. Keep bringing the same ball back to the two surfaces so the comparison doesn't disappear completely. If the difference is subtle, use a clearly bouncy ball and a thick folded blanket so they can actually see it.

Why it works: The surface changes how much energy the ball keeps after impact, so the same ball bounces differently on hard and soft materials.

Age range tweak:

• 18-24 months: Let an adult do the low drops and let the child chase the ball.
• 24-36 months: Let them release the ball from the same low height over both surfaces.

6. Warm-Water Ice Melt

Freeze one large block of plain water in a wide food container and tip it into a shallow tray. Give your toddler a small cup of comfortably warm, never hot, water. Let them pour a little over the ice and watch the surface change. Keep the tray on a towel and supervise the water closely.

Let your child choose where the next little pour goes instead of covering the whole block at once. The grooves and shiny wet spots give them something to look for between pours. If they get more interested in touching the puddle than the ice, that's normal; just keep the water comfortably warm and the loose ice pieces too large to mouth.

Why it works: Warmer water transfers heat into the ice, so the child can see grooves, puddles, and melting appear where the water lands.

Age range tweak:

• 18-24 months: Let an adult hold the cup together with the child and make one short pour.
• 24-36 months: Let them pour onto different parts of the ice and compare where it melts fastest.

7. Cardboard Tube Stand-or-Roll

Use one large clean cardboard tube with smooth ends. Set it upright and give it a gentle push, then lay it on its side and push again. Let your toddler keep changing the tube between standing and sideways positions.

This one works well with toddlers who immediately want to grab the tube and change it themselves. Give them a clear floor space and let the same tube tip, roll, stand, and fall a bunch of times. You can name what happened, but the shape is doing most of the teaching for you.

Why it works: The same tube behaves differently depending on which part touches the floor: the flat end can stand while the curved side can roll.

Age range tweak:

• 18-24 months: Set up each position for them and let them push.
• 24-36 months: Let them choose upright or sideways and predict whether it will tip or roll.

The Bottom Line

At this age, the experiment usually works best when your toddler can change something with their own hands and see the result right away. A ramp gets higher, a ball lands somewhere softer, a sponge moves water, or a paper shape falls differently.

You don't have to turn any of that into a lesson while it's happening. If they keep rebuilding, dropping, pouring, rolling, or pushing because they want to see it again, they're already doing the useful part.

Want to have these ideas in one place, customized for your kid in just a click? Grab our free Screen-Free Activity Finder.

One mom told us: "My kid was about to have a full meltdown and I had nothing. Pulled up the Screen Free Activity Generator and it gave me 'Tupperware Tower Challenge.' I dumped every plastic container from my kitchen on the floor and told her to stack them. She went from tears to totally absorbed in about 30 seconds. Spent 25 minutes stacking, crashing, matching lids. I just sat there drinking my coffee. Sometimes the simplest stuff works the best."

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