# Hello, Goodbye, Adios, Aloha

I say hello, I say goodbye
One moment I'm low, the next I am high
I can make you see something you did not see
The invisible can be seen through me.

What am I?

## 2 Answers

I think the answer might be

Wave

I say hello, I say goodbye

To wave means to move one's hand to and fro to greet or bid farewell

One moment I'm low, the next I am high

I can make you see something you did not see

Visible light is a wave (has wavelike properties)

The invisible can be seen through me.

Invisible parts of the electromagnetic spectrum also manifest as waves (infrared, ultraviolet) and invisible phenomena can sometimes also be detected using waves.

• Well done! Correct in every way, although ROT13: Yvarf 1 & 3 jrer zrnag gb or nobhg n unaq jnir - lbh pna jnir ng fbzrbar gb trg gurve nggragvba – Astralbee Apr 12 '19 at 10:10

The sun ?

I say hello, I say goodbye

Dawn and Dusk.

One moment I'm low, the next I am high

From our perspective the sun goes up then down during the day.

I can make you see something you did not see

With its light.

The invisible can be seen through me.

For this one, i suppose it's about the flour or the dust or things like that, in the air that we can only see with the light directly on it.