Clear (laser can pass thru), viscous, easy-to-find substances?

Question

It's for a chemistry experiment. So far I've: -glycerol -mineral oil
They should be slow-moving, and very viscous, but not solid; they have to be liquid. Furthermore, I have to be able to pass a infrared laser sensor through the liquid without the sensor picking up the liquid as an object. Also, they can't be ridiculously hard to find substances, nor dangerous ones.

answer w/ most substances gets 10 pts, and my sincere respect.

Uh..thx Johnnie 8, but my question actually revolved around viscous substances that pass thru laser. I'm actually using a infrared sensor, which isn't as powerful as the lasers NASA uses. But thx for the info!

Answer 1

Karo syrup is the answer., also clear vegetable oil, glycerine,
There also is a material called water glass that is clear, viscous , it used to be used to attach labels on glass.

Answer 2

I did work with NASA and wrote the maintenance Manuel for the 1 Gig Watt laser. When we aligned the liens it was critical to make sure the surface was not perpendicular to the laser. It was so powerful it would burn a place in the liens. Lasers are used for a lot of gas detectors like in a plant if it is a heavy gas u look near the floor ,and if it is a light gas u put it up in the top of the building . Excellent safety alarm systems.

Answer 3

Glucose (Karo corn syrup from super market) would be another easy one to find.