Step 2: The glue
To make one kg of glue you need 3/4 cup of starch, 1/2 cup of sugar and about 800 mL of water
What you are going to do is to boil half of the water (be careful with your little assistant if you have, do not let he/she unattended or near the hot water we don't want to turn a nice activity in a tragedy)
Dissolve the corn starch and the sugar in the remaining cold water (is very easy to dissolve it in cold water and your assistant can help here, and please do not try to do it in hot water because the starch become very viscous in contact with hot water and will be impossible to dissolve it)
Add your starch/sugar solution to the hot water, keep warming and stir gentle with a spoon.
After a few minutes of stirring you will notice that the solution turns viscous. When it has a consistency like the one in the photo is ready.
Let it cool. If you done it well, it should look like the photo when is cool (cooling process will take some hours, so be patience and do not try to use it hot, it simply doesn't work)
I recomend you not make too many because it spoils quickly (starch, water and sugar not are only a good glue, also they are a good media for mold and other microorganisms to grow), if you need more, then make more.
As the project could take two or three days to be ready you can keep your glue in the refrigerator to extend its shelf life. If you want, you can add sodium benzoate as preservative (1g/kg) and keep it at room temperature
This is important: If you keep your glue on refrigeration and, when you try to use it, you find it looking like a gelatin with a lot of water sorrounding it, don`t worry, just let it harm at room temperature, then break the gel and mix it again (squezze it with your hands its the best way to do it). In despite of the change of texture it still works and you can use it.
Last but not the least: This glue is also enviroment friendly: is natural, non toxic and, is totally biodegradable.