“When one door closes another door opens, but we so often look so long and so regretfully upon the closed door, that we do not see the ones which open for us.”
“God has strewn our paths with wonders, and we should certainly not go through Life with our eyes shut.”
Both attributed to Alexander Graham Bell
• Waves can be divided into two categories: mechanical waves and electromagnetic waves. Mechanical waves include waves in water or air, sound waves, and ...