This refers to the ability to identify common objects without sight or hearing, so eyes closed or covered. Today I did an activity where I gave my carer a non see through cloth bag and asked him to put in common objects, while I sat in my easy chair blindfolded. He then handed the bag to me and I felt and correctly identified all objects. Mine you, he told me what one was.
If you are playing stereognosis games with your child, start be showing them the objects before blindfolding them, then as they improve don’t let them know what the objects are before blindfolding them, to ensure they get no clues from objects not being in the right places as you put them in the bag, ensure they are blindfolded in the living room or at the table as you collect objects.
When you have your blindfolded child feeling an object, have them describe what the objects feels like not just name the object. So for example, you give them a piece of lego, see if they can describe the shape and the size, how heavy the object is, how many rough holes there are and what it can be used for, and anything else they can describe.
play with friends, each player gets a point for every piece of information about the objects and 5 points for naming it. Blindfold everybody at the start so no one has the advantage of seeing others go first.
or blindfold your child and have them search for an object in a pile of objects, after a few goes, blindfold yourself to remove the temptation to help them.
another idea have a toy box covered with a blanket and blindfold two players. Give an object to player 1 to describe to player two, but do not name the object, then hide the object in the box again for player 2 to find still blind, asking player one questions while feeling through the box, when he thinks he has found the object he must return it to player 1 to check by feel, if incorrect try again, if correct remove both blindfolds and let them both see the object.
Or have players sit in a circle and take off their shoes and place them in a pile in the middle, after blindfolding everyone at once or in turn. They have to find their shoes, either one person at a time or everyone at once, if one at a time, the shoes go back into the middle so everybody has the same size pile. If only one person is searching at a time to ensure an equal playing field it might be good to have those waiting for their turn waiting in darkness. To make it easier let them put one shoe of the pair so they can compare it against the pile. This game could also be played with other objects like pillows, or stuffed animals.