A hot air balloon is a balloon aircraft which is lifted by hot air.
Cold and warm fronts are formed where bodies of cold and warm air meet.
Capacitors store electrical energy in the form of electric charge.
A type of rotary engine of high efficiency
Electrochemical processes in a lead-acid battery produce electric current.
The diameter of our galaxy is about 100,000 light years; it contains more than 100 billion stars, one of which is our Sun.
A fuel cell provides environment-friendly electric energy produced by the chemical reaction between oxygen and hydrogen.
The Space Shuttle was a manned, reusable spacecraft operated by NASA.
The Earth is divided into 24 time zones. Standard time is the time used within time zones.
The Voyager space probes were the first man-made objects to leave the Solar System. They gather data about outer space and carry information about humanity.
In 1946 a Hungarian scientist was the first person to detect radar echoes from the Moon.
By varying the position of the light source, you can examine the shades projected onto the planes of the coordinate system.
Direct action pumps and suction pumps are among the simplest water pumps.
Simple harmonic motion can be considered to be the one-dimensional projection of uniform circular motion.
The Global Positioning System consists of 24 satellites but only 4 have to be visible for positioning.
A force can be measured by measuring the twisting of the torsion wire in a torsion balance.
A dynamo converts mechanical energy into direct current.
The largest satellite of Pluto is Charon.