List one or two phenomena that contain scientific truth in daily life

List one or two phenomena that contain scientific truth in daily life

Refraction gravity of light

Is the seesaw a translational motion or a rotational motion

When playing a seesaw, the movement of the seesaw is rotation. However, the situation of a seesaw player is more complicated: if the state of the seesaw and the person remains unchanged, the seesaw and the person rotate together; if the person always keeps vertical with the ground, the person's movement is translation; if the person is still shaking at will when playing the seesaw, Then human motion is not rigid - neither translation nor rotation

Hurry, what time is it?

One of 1-24, unless you're not on the earth, I have to answer. I'm sure your answer is included
hey

English translation
March 23, 2010`~`

what time is it?

What time is it now

what time is it ?
what's the time now ?

English translation
What time is your watch now
Why use by instead of on your watch

what's the time by your watch?
The standard Chinglish above

What time is it now

What time is it
What is the time

What time is it now

What's the time?

What time is it

What time is it in Italy
2010.6.27 10：50

Italy is located in the East District, 7 hours away from us. It should be 4:50 on June 27, 2010