1-The world geothermal comes from Greek words meaning ‘Earth’ (geo) and ‘heat’ (thermos).
2-Sound can’t travel through a vacuum (an area empty of matter).
3-The speed of sound is around 767 miles per hour (1,230 kilometres per hour).
4-When traveling through water, sound moves around four times faster than when it travels through air.
5-The scientific study of sound waves is known as acoustics.
6-The refractive index of water is 1.3 while the refractive index of air is 1.0003, meaning that air only slightly slows down light.
7-Sunlight can reach a depth of around 80 metres (262 feet) in the ocean.
8-Photosynthesis is a process that involves plants using energy from sunlight to convert carbon dioxide into food.
9-Scientists study the properties and behaviors of light in a branch of physics known as optics.
10-Famous Isaac Newton quotes include: “Plato is my friend – Aristotle is my friend – but my greatest friend is truth.”
11-Electric potential energy is measured in volts.
12-Electric current is measured in amperes (amps).
13-The world’s biggest source of energy for producing electricity comes from coal.
14-Electric eels can produce strong electric shocks of around 500 volts for both self defense and hunting.
15-In some countries such as Denmark and Portugal, wind power contributes around 20% of the total electricity production.
16-Large groups of wind turbines are called wind farms.
17-Windmills have been around for a long time, they were used in Persia (Iran) as far back as 200 B.C.
18-Solar cells convert light energy into electricity.
19-The largest solar power plant in the world is found in the Mojave Desert, USA.
20-Spacecraft and space stations such as the International Space Station (ISS) often use solar panels to generate power.