I would advise against honey as it is often creates a mess and can cause the unfortunate deaths of smaller ants such as yours. Sugar water is a far better option in this regard and should be offered in tiny drops using a pipette.
Otherwise, you may choose to use gel-based synthetic foods although I would suggest that you wait for your colony to approach a considerable size in order to prevent wastage and for optimum results. You can purchase pre-made ones such as Blue 100 from Byformica (drtmiller) or mix your own. I have written a guide while back which may be useful to you (http://www.formicult...ch-threadguide/).
Blue 100 might not be ideal in this case as Solenopsis invicta was found to be unsuitable with the diet it was based on. However, I have had positive results with Solenopsis geminata with my own rendition so perhaps you might like to try it.
Finally, Solenopsis invicta can grow very quickly if large quantities of protein are offered. Since you mentioned that this was to be observed by children, it might be wise to limit the colony to a manageable size to facilitate easier handling. Fluon would be excellent to prevent accidents and headaches so it might be worth investing in.
Edited by Etherwulf, December 16 2015 - 8:13 AM.