Does empty cans mean stupid people?

Hi, everyone .
I’m pleased cause I’m sending this e-mail.Actually, I love writing in English. When I come across something that I can’t understand , I send right away to my respectable demonstrators . Indeed , I encountered three idioms . I looked them up in many dictionaries , I found one of them but I couldn’t find the other two .
here are the idioms : 1- EMPTY cans (I know that this expression means “stupid people” what I need to know is what is the influence of writing the word “empty” in capital letters?

    The second idiom is" do more noise" . I don't know the meaning of this idiom.
    The same thing with this idiom "try to be older"

thanks for your time ,and I’m sorry for bothering you.

In this case the word “empty” symbolises lack of brains or intelligence.*

“do more noise” is not an idiom I have ever heard of, and, indeed, does not seem like correct English. Do you have any more context?

Likewise, I am not familiar with any idiom “try to be older”. That could possibly be used literally, when referring to someone attempting to act in a more mature way. Again, do you have any more context?

*Sorry, I may have misunderstood your question. If you mean that the dictionary wrote “EMPTY” in capitals, I don’t know why that was done. It may be something to do with their style rules or layout rules. Was it an online dictionary that you can give a link to?

Thank you so much for your help . I 've found out that " empty cans do more noise " is a proverb.But what I’m wondering about is that can we use the verb do with noise. there is one more thing I want to ask you about.If you don’t mind ,tell me if there were any mistakes with my writing in this and the previous e-mail.
Again thank you.

You have that slightly wrong. The proverb is ‘empty cans (originally ‘empty vessels’) make most noise’.

Your writing looks very messy because you are making many mistakes with spacing. You need to put a space after each comma or full stop, but no space before. You need a space before an opening quote, not after. You need a space after a closing quote, not before. Please check these examples:

If you don’t mind ,tell me if there were any mistakes – INCORRECT SPACING
If you don’t mind, tell me if there were any mistakes – CORRECT SPACING

… sending this e-mail.Actually, I love writing in English … – INCORRECT SPACING
… sending this e-mail. Actually, I love writing in English … – CORRECT SPACING

I 've found out that " empty cans do more noise " is a proverb – INCORRECT SPACING
I’ve found out that “empty cans do more noise” is a proverb – CORRECT SPACING

My musician sons, native English speakers, also talk about ‘doing noise’, so maybe it’s just musicians’ slang.

Thanks alot. I’ll follow your advice. Is spacing my only mistake or are there any other mistakes?

There is no word “alot”. It is two words: “a lot”.

From your original message:

“I’m pleased cause I’m sending this e-mail.” – In casual speech, the “be” in “because” is often dropped. However, this contraction does not transfer to writing very well, and is best avoided except in certain cases (such as very casual writing, song lyrics, or written dialogue where it is necessary to emphasise the casual nature). In other cases, such as here, it’s best to write “because” in full. If you do write “cause” then it should strictly have an apostrophe at the start: 'cause.

“When I come across something that I can’t understand, I send right away to my respectable demonstrators.” – “respectable demonstrators” is very odd. You may mean “respected teachers” or something like that. I’m guessing that you mean “send it” rather than just “send” (though the latter is not actually impossible).

“I looked them up in many dictionaries, I found one of them but I couldn’t find the other two.” – This is a comma splice (two independent clauses joined only by a comma). You could use a semicolon instead of the comma.

“here are the idioms” – “Here” needs to be capitalised as it is the start of a sentence.

“I know that this expression means ‘stupid people’ what I need to know is what is the influence of writing the word ‘empty’ in capital letters?” – This is a run-on sentence. You could fix it with a full stop or semicolon after “stupid people”. “influence” seems to be the wrong word. You may mean “effect of” or “reason for”.

“thanks for your time, and I’m sorry for bothering you.” – “Thanks” should be capitalised because it is at the start of a sentence.

I haven’t heard of this idiom, but a related one is “act your age”.