Posting and Slotting
Your child pushes a plastic lid through a slot cut in a tub, hears it land, and then takes the tub lid off and finds it again.
- Age
- Under 2 to 3, best at 2
- Setup
- 2 min
- Play
- 5 to 10 min
- Materials
- Household only
- Mess
- None
- You
- Set it up, then leave
Activity KG-A014
What you need
One container and one slot is the whole of it. The size of the slot is the only thing worth getting right, and getting it right takes a minute.
- A tub with a push-on plastic lidx1 Or: an ice cream tub. Or a baby wipe tub. Or a coffee tin with its plastic lid. The lid has to come off easily, because half of this activity is opening it to get the discs back. A clear tub beats an opaque one at this age: watching the discs land is the answer to where they went.
- Plastic milk bottle lidsx8 to 12 Or: jam jar lids. Or wooden discs. Or coasters cut from a cereal box. A milk bottle lid is about 4 cm across, which will not drop through a toilet roll tube, and that tube is the household test for what is safe in a two year old's hands. It is also flat, light and easy to pinch by the rim.
- A craft knife or sharp scissorsx1 For the slot, which is an adult job and takes about thirty seconds. Cut plastic has a burr along the edge, so the tape below finishes the job.
- Masking tapea strip Or: sticky tape. Or a fabric plaster. Folded over each long edge of the slot it takes the roughness off the cut and stays put for months of posting.
How to set it up
- Hold a disc against the tub lid and mark a line 1 cm longer than the disc is wide.20 sec
- Cut along the line and open it to about 3 mm wider than the disc is thick, and cut only the one.30 sec
- Fold a strip of masking tape over each long edge of the slot.30 sec
- Post two discs yourself, take the lid off so he sees them lying in the bottom, and put it back on.30 sec
What to say and what to do
Say
In it goes. Gone.
Shall we open it?
- Then hand it over. The tub does the rest of the talking.
Do
- Take the lid off every single time he asks, however many times that turns out to be. The coming back is what makes the going in worth doing.
- Hold the tub still for the first few goes, then let go of it. A tub that slides away across the table turns aiming into chasing.
- Keep it to one slot and one kind of disc. The plainness is what lets this run on its own at two.
Let be
- Discs dropped down the side of the tub instead of through the slot.
- The whole tub tipped out and refilled by hand, with no posting in it at all. Emptying is the half most children do first.
- The same six lids posted twenty times over. Repetition is what this one is for.
What it looks like when it is working
- The disc gets turned in his fingers to line up with the slot before it reaches the lid.
- She stops looking into the tub and starts listening for the drop instead.
- He posts several in a row without checking your face between them.
- The lid comes off on her own, and the whole lot goes in again.
What to expect at each age
Before two
Pushes the disc at the lid flat-on and wants it turned edge-up for him, and mostly wants the tub opened. Roughly one in three goes through.
Turning the disc to match the slot arrives around the second birthday. Before that, the discs going in at all is the result.
Lasts 3 to 5 minutes
At two
Turns the disc upright before it reaches the slot and posts most of them first go. Empties and refills the tub several times over in one sitting.
Deciding which thing goes in which hole comes later, and it needs a second container before it makes any sense.
Lasts 5 to 10 minutes
At three
Posts without looking, counts as he goes, and starts wanting other things to fit: coins, buttons, lolly sticks.
A lid with slots cut in several directions is the natural next thing, and it is a different job: turning the disc to match the angle, rather than making one slot work.
Lasts 10 minutes, usually inside a longer game
When it goes sideways
All of these are the tub telling you something about the fit, and none of them need anything new bought.
The disc will not go through
The slot is a shade too tight, and it is asking for more force than a two year old hand makes.
Run the knife down the slot once more to open it a couple of millimetres. The disc wants to drop through under a light push rather than be forced.
He posts one and wanders off
The discs went in and never came back, so the loop has no end to it and no reason to start again.
Take the lid off and tip them out in front of him. Once he has watched the discs return, the posting has a point, and most children then go round the loop five or six times.
She is chewing the lids
Ordinary at two, and plastic lids are good chewing. It is investigation rather than a problem.
Use the biggest discs in the house, jam jar lids rather than bottle caps, stay at the table, and it settles within a couple of sittings once the hands find the more interesting job.
It is over in two minutes
Eight discs is eight posts, and at two the length of a run follows the size of the pile.
Put twenty in. A tub of lids collected on the windowsill over a fortnight runs about four times as long as a handful does.
Making it harder
Four rungs, all of them made out of the recycling.
One slot, one kind of disc
- Ready when
- This is where everybody starts.
- What changes
- A clear tub, one slot cut to fit, eight milk bottle lids.
- What is new
- Letting go of something on purpose, and finding out that it still exists.
A narrower slot
- Ready when
- She posts eight without the disc catching on the way through.
- What changes
- A fresh lid with the slot cut just 2 mm wider than the disc.
- What is new
- Turning the disc to match the slot before it gets there, which is the first real aiming in this.
A round hole as well
- Ready when
- He turns the disc without having to look at it.
- What changes
- A second container with a round hole for a ping pong ball or a cotton reel, offered alongside the first.
- What is new
- Choosing between two containers, which is where sorting begins.
Several openings, several shapes
- Ready when
- She picks the right container without trying the wrong one first.
- What changes
- A shoebox with a round hole, a slot and a square cut in it, and a mixed bowl of things to post.
- What is new
- Matching shape to opening, which is a thinking job rather than a hand one.
Stop with the lid off and the discs back in their bowl, because that is how the next go starts fastest. A tub left full gets shaken rather than posted.
How to keep it safe
Small parts and one cut, so three lines cover it.
- Discs of 4 cm and wider. The household test is a toilet roll tube: anything that drops through it is too small for a child under three, and a milk bottle lid will not.
- You cut the slot, and fold masking tape over both cut edges before the tub reaches the table.
- Count the discs back into their bowl at the end and keep the tub on a shelf between sittings, especially if there is a baby crawling.
- Stay at the table while a child is still putting things in her mouth, which covers most two year olds.
Why this helps
From the guide The claims here follow our guide on hands, pencils and the grip question.
Posting is a two year old's experiment in things carrying on existing. The disc goes in, it is gone, the lid comes off and it is back, and that loop is worth running twenty times because the answer is the same every time. Keeping it to one container and one slot is what keeps the answer clear, because nothing else in the setup is asking a question.
The hand work underneath it is turning. A disc has to be stood on its edge and lined up with a slot before it will go, and that is a rotation of the wrist rather than a squeeze or a grab. It is the same movement as a card into a letterbox or a coin into a machine, and it is one of very few things at this age with exactly one right answer, given instantly and by the object itself.
Skill practised: wrist rotation and aim, with an answer every time
It is a disappearing trick with a lid on it, not shape sorting. A two year old posts because the disc goes away and then comes back.
Where a set helps
A tub with a slot cut in it does this perfectly well, and it is where we would start with any two year old. The Slot and Post Frame we print is the version that keeps going: one frame takes a narrow slot, a round hole and a wide one, so it grows into the sorting stage instead of being re-cut, and the pieces are sized to the 4 cm rule already. The ice cream tub version is the same activity, and nothing is missing from it.
One a week, at your child's age
We publish one new activity a week at each age, in exactly this format. How wide to cut the slot is nearly the whole of this activity, and it is easier to see once than to read twice.
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Questions parents ask
How is this different from the coin drop activity?
They start from the same tub and then go different ways. This one keeps to a single slot and a single kind of disc, so the whole question is where the disc went and whether it comes back, which is why it works from around eighteen months. The coin drop cuts slots in three directions in the same lid, so the disc has to be turned to match the angle before it will go through, which makes it an aiming job rather than a disappearing one. Most children do this one first and take on the angles a few months later, often with the same tub.
What size should the slot be?
One centimetre longer than the disc is wide, and about 3 mm wider than the disc is thick. That lets it drop through under a light push while still needing to be lined up first. If the disc goes through whichever way it is held, the slot is too big and the activity has lost its job.
What can I post if there are no milk bottle lids?
Jam jar lids, wooden discs, poker chips, the plastic lids off cream tubs, or discs cut from a cereal box. Anything flat and at least 4 cm across. Keep them all the same thickness for the first few weeks, because one thick disc in a pile of thin ones jams in the slot, and a jammed slot reads to a two year old as the tub being broken.
He only wants the lid taken off.
That is the other half of the loop, and for plenty of children it comes first. Opening the tub is where the discs come back from, and posting only becomes interesting once he knows for certain that they do. Take the lid off as often as he asks for a few sittings, and the posting fills in around it.