Here are two activities for children ages 2-5 that are very easy to make at home.
The first is can be used as an extension to the Montessori Knobbed Cylinders:
Photo Credit: Creative Commons ©Jess and Colin
Knobbed Cylinders are a Montessori tool used to help children explore and learn about dimension.
Knobbless cylinder materials such as the one below are sometimes used as an extension to the knobbed cylinders (these are also available in wood). You will note however, in the video below that demonstrates how to present the knobbed cylinders, having knobbed cylinders in varying colours presents an obstacle for the child whom you want to focus on size. The fact that colour is present can be a distraction for the child; his/her attention may end up being drawn to not only the size of the materials but the colour as well.
Here, a piece of cardstock with red circles in various sizes, and from smallest to largest, is presented to the child with the matching pieces in a box on the right hand side.
*If you are teaching a child to read in English, you would have the box on the left hand side as English is read left to right.*
The child is invited to match the circle (pieces) to the circles on the strip of cardstock.
*There two things to note when using this activity: the Control of Error that is naturally in the Knobbed Cylinders (pictured above) is almost removed in this activity. The child cannot 'feel' when they have incorrectly matched a circle to the one on the strip, therefore it may be difficult for them to self-correct. For this reason, I showed the child how to compare the circles by placing a circular piece under the circle on the strip to see if they matched. Additionally, a child cannot note depth, length or height using the above activity.*
I would not suggest using knobbless cylinders above as the primary tool for teaching children about size/dimension, but as an extension, these might be enjoyed by children. They are also easy to make on your home computer using MSWord or similar programs. Those pictured were downloaded free and I have searched and searched for the link but it appears the site that had them either no longer offers them as a free download or no longer exists because I can only find these as a download to purchase subhana'Allaah.
You can view a video that explains the purpose of Knobbed Cylinders and how to use them here insha'Allaah.
The second activity helps children match objects to their outlines:
You can add a degree of difficulty to the activity by tracing only half of the object and invite the child to match the object to the partial outline.
To make this all you will need is a shoe box, 8 squares of blank white paper (identical in size), onto which you will trace the shapes' outlines and partial outlines, and four objects whose outlines are easily recognizable. Simply trace the outline of each object on to a separate piece of paper and on the remaining four pieces of paper trace only half of the object's outline (for each object).
You would line up each of the first four pieces of paper that show the complete outline of each object, in random order (do not have the other four pieces of paper with the partial outlines in the box when you are presenting the child with the complete outlines). Take the objects out of the box one at a time and show the child how to compare the object to each outline to find its match. Slowly compare each object before placing it on the correct outline. Repeat this for each object. Once you've matched all four objects, place them back into the box along with the papers. Invite the child to do the activity insha'Allaah.
Once the child has shown mastery of matching objects with complete outlines you can introduce the partial outlines in the same manner above. Be sure that you only have the pieces of paper that have partial outlines on them in the box when presenting them.
Both of these activities are relatively simple to make and require very few materials, all of which can be found in the home insha'Allaah.