Do You Know?
1. According to my science textbok, sunlight is white. Then why does it appear yellow to the eye?
2. How is a hissing sound produced when water falls on a hot surface? 
3. Many websites have a "Captcha" to check that a human being is using it. How does this work? 
4. In many competitions, we often "root for the underdog", that is, support someone who would ordinarily be expected to lose. Why do we do this?
5. I always see wind coming from somewhere. Where does wind come from?