Is it illegal to bring this onto a university?

I think it would be fine the "possession of drug paraphernalia", is used to denote any equipment, product, or material that is modified for making, using, or concealing drugs, typically for recreational purposes. Drugs such as cocaine, heroin, marijuana, and methamphetamine are related to a wide range of paraphernalia. Paraphernalia generally falls into two categories including user-specific products and dealer-specific products.

User-specific products include glass hashish pipes, crack cocaine pipes, smoking masks, hashish bongs, cocaine freebase kits, syringes, roach clips for holding the burning end of a marijuana "joint". Some stores sell items for growing hydroponic marijuana, such as guidebooks, fertilizer, and fluorescent grow-lights. The term paraphernalia also refers to items such as hollowed-out cosmetic cases or fake pagers when used to conceal illegal drugs, or products purported to cleanse an individuals system of drug residues to increase the individual's chance of passing a urine analysis for drug use.

If you are speaking to university kids you do not need to show them what it looks like. They already know.

Get a piece of hemp rope, a Bic lighter and an ash tray. Light it up and let it burn in the ash tray. It has been proven in a number of studies that you remembers smells best of all. If they smell it as you talk, they are more likely to remember it and what you said.

Why do you need a 'visual aid'? That will do nothing to further your speech. Use Powerpoint if you really want .

It is called possession. Depending on how much you have, it is either a citation or fine. If you have a lot, they can slap you with intent to sell. That is when you are screwed.

Don't be stupid, don't bring drugs as show and tell.

That can be classified as a pseudo-narcotic and you can get in trouble if they choose to press it. I was accused of pseudo-drug charges for jokingly having baking soda in a little jar.

Get some rolling papers and roll up some sage or oregano joints nothing illegal about them.