7 STEM Activities for Toddlers Ages 18-36 Months Who Won't Sit Still

Some toddlers will happily sit at a table and poke at an experiment. Other toddlers would rather sprint down the hallway holding the experiment.

If your kid is in the second group, movement can carry most of the activity. They can chase a rolling ball, walk across two different surfaces, squeeze through a box-sized gap, run with a scarf, or step onto a cushion and feel it change under their feet. They're still comparing what happened; they're just doing it with their whole body instead of from a chair.

Keep the routes short, clear, and low to the ground. The goal here is to give all that movement something interesting to bump into, especially on the days when asking them to sit still is clearly not happening.

1. Roll-and-Chase Ball Path

Roll one large soft ball down a hallway or gentle outdoor slope and let your toddler chase it. Try a stronger push, a gentler push, or a different starting spot. Keep the path clear and the slope mild.

A hallway is great because it naturally gives the ball somewhere to go without a complicated setup. Let your child bring the ball back and choose whether the next roll should be soft or strong. The running keeps them involved, while the changing push gives you something simple to compare each time they return.

Why it works: The push changes the ball's speed and distance, and the toddler gets immediate feedback by running after the result.

Age range tweak:

• 18-24 months: Use a short clear path and slow rolls.
• 24-36 months: Try two starting spots or push strengths and let them predict which roll will go farther.

2. Footstep Sound Walk

Choose a clear path that crosses a hard floor and a rug or folded blanket. Walk the path together using normal steps and listen to the sound under each surface. Go back and repeat with slightly firmer steps, keeping the movement controlled and the path clear.

Kids who won't sit still often notice sound better when they're the ones making it. Walk the same little route a few times and let them stomp only if the volume stays comfortable. A hard floor and a thick rug usually give enough contrast that you won't need to turn it into a formal listening exercise.

Why it works: Hard flooring and soft fabric handle vibration differently, so the same footsteps usually sound sharper on the hard floor and quieter on the softer surface.

Age range tweak:

• 18-24 months: Walk slowly together across one hard and one soft surface while an adult points out the sound change.
• 24-36 months: Let them repeat the path and compare normal steps with slightly firmer steps on both surfaces.

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3. Big-Step Small-Step Walk

Place one large towel at the start of a clear floor path and another several feet away as the finish. Walk the path together once using tiny steps while an adult counts aloud, then walk it again using bigger comfortable steps. Compare which trip used more steps.

Don't worry about perfect counting. The useful part is that your child can feel one version taking lots of tiny steps and another getting them there faster. Let them invent a hilariously giant step for the last round if they want, as long as the path stays safe and they're still walking rather than leaping.

Why it works: The distance stays the same while step length changes, so longer steps need fewer repetitions to cover the path.

Age range tweak:

• 18-24 months: Use a very short path and let the adult do the counting.
• 24-36 months: Make the path a little longer and compare tiny, normal, and big steps.

4. Shadow Step Chase

Stand outside when clear shadows are visible. Let your toddler step on your shadow, move away, and find it again. Raise one arm, crouch, or turn sideways and watch the shadow change. Stay away from traffic and hot surfaces.

The game gets easier when the sun is low enough to make a clear shadow but the ground is still comfortable. Let your child chase your shadow first, then notice what happens when you turn or crouch. Preschool-style explanations aren't necessary here; moving the body and seeing the shadow move with it's the interesting part.

Why it works: The shadow changes shape and position when the body moves relative to the light.

Age range tweak:

• 18-24 months: Use one clear adult shadow and simple arm movements.
• 24-36 months: Let them move their own body and compare long and short shadow shapes.

5. Turn-the-Box Gate Test

Place two empty laundry baskets on the floor to make a wide, soft-sided gate. Give your toddler one large empty rectangular cardboard box that's noticeably wider in one direction than the other. Let them carry the box toward the gate with the wide side facing forward, then turn the same box and try again with the narrow side facing forward. Move the baskets only enough to keep the challenge easy and frustration low.

Use a box your toddler can carry without blocking their view. The first time it bumps the baskets, give them a second to figure out what happened before turning it for them. Kids often love the feeling of finally fitting through, and they'll usually run back to try the awkward direction again on purpose.

Why it works: The box keeps the same shape, but turning it changes how much width has to fit through the same opening.

Age range tweak:

• 18-24 months: Use a very wide gate and help turn the empty box before the second pass.
• 24-36 months: Let them test both orientations and decide which way fits through more easily.

6. Scarf Run Air Test

Give your toddler one large lightweight scarf to hold by one corner. Walk or jog slowly together and watch how the scarf streams behind. Stop, walk again, then move a little faster in a clear safe area.

Keep the scarf short and light enough that it trails instead of wrapping around the child. Start by standing still, then walk, then pick up the pace a little so the change is obvious. A kid who loves running will usually do the repeating for you while the scarf makes the air visible.

Why it works: Faster movement pushes more air past the scarf, changing how far it lifts and trails behind.

Age range tweak:

• 18-24 months: Walk slowly while an adult stays beside them.
• 24-36 months: Compare standing still, walking, and a short gentle jog.

7. Cushion Step Squish Test

Lay two large floor cushions several steps apart. Let your toddler step onto one, step off, then step onto the second. Put a folded blanket underneath one cushion and compare how high, soft, or wobbly the two spots feel. Keep everything low and stay within arm's reach.

Use two genuinely different setups so the child can feel the contrast through their feet. Hold a hand if balance is still shaky, and keep both cushions flat enough that stepping off is easy. If they start bouncing on one, bring the pace back down and return to stepping and comparing.

Why it works: The support underneath changes how much the cushion compresses and how stable it feels under body weight.

Age range tweak:

• 18-24 months: Use one low cushion and hold a hand for balance.
• 24-36 months: Compare two low setups while an adult stays beside them.

The Bottom Line

For a kid who needs to move, chasing, carrying, stepping, running, and squeezing through a gap can be the experiment. You can still give them something to compare without asking them to suddenly become the child who sits nicely at a table for twenty minutes.

That makes these especially handy on high-energy days. Set up one clear thing to notice, let their body do most of the work, and keep the explanation short enough that they don't disappear before you finish it.

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