Question

A drinking glass at a crime scene contains a clear colorless liquid that may be water or alcohol. As the investigator, you know that the densities of alcohol, water, and ice are 0.79g/mL, and 0.92/mL. Design a simple method to determine the identity of the mystery liquid. Explain your design.

Answer 1

Taste it.

Answer 2

You didn't give the density of water but I suppose we can assume it is 1.0 g/mL.

I would NEVER taste it even though some one told me it was alcohol or water. :-). I would carefully smell it.

OK so you want to utilize the densities.
Place an ice cube in the liquid. If the ice cube floats the liquid is water. Ice is less dense than H2O so it floats. If the ice cube sinks the liquid is alcohol. The ice cube is more dense than the alcohol so it sinks.

Answer 3

We know that water's density is 1.0g/cm3. We also know that ice floats on water, because its density is lower than water in liquid form. However, alcohol has a much lower density than water ice. Which suggests that it will sink.

To simulate this, we can simply put an ice cube into the glass filled with the unknown substance. If the ice cube floats, its water, but if it sinks, it is alcohol.

Answer 4

I'm a grade 9 in 2020 looking up the same question hahahah, they really don't change the curriculum.

Answer 5

Same lol

Answer 6

same here lol

Answer 7

same here lol i think they won't change the curriculum so good for us

Answer 8

My teacher is insane and I’m fighting against her with the vice principal, it’s the twentieth day of school. How yall holding up? Thanks for the help btw

Answer 9

it's 2022 and I'm looking up the same question lolll

thanks for the help!!!

Answer 10

same here i am in 2023 crazy how it still hasn't changed