Light travels at precisely <span>299,792,458 metres every second (abbreviated to 3 x 10^8 metres every second but let's be precise) There are 60 seconds in every minute (</span><span>299 792 458 x 60 = 17,987,547,480m) 60 minutes in every hour (17,987,547,480 x 60 = 1,079,252,849,000m) 96 hours in 4 days (</span><span>1,079,252,849,000 x 96 = 10,360,827,350,000m) </span><span>Now let's convert to km to make this number (slightly) more manageable (</span>10,360,827,350,000 / 1000 = <span>103,608,273,500km) </span>Light travels <span>103,608,273,500km in 4 days - that's the equivalent of going around the equator of the earth 813,124 times!</span><span>
You can use a universal indicator. The color of the universal indicator before contact with other chemicals is green, which is the pH of 7. We know that bottled water is pH 7. So when we put a few drops of universal indicator, the color would be green indicating neutral pH.
