If your target audience is a general population, you should not be using icons alone to convey anything meaningful. By doing so, you have made assumptions that are unlikely to be appropriate to a general audience.
You should not assume icons or UI elements are known to your users, as those really are a part of a world of knowledge and conventions that people have to be aware of.
After more than a year of using her tablet to read Email, my mother had no idea the Gmail application can be used to write an email.
Why? Because after more than 12 months of using an application, she still failed to recognise two vital core-feature UI components. Because they were just fucking icons.