Voyager Mission
In 1977, NASA launched two small spacecraft called Voyager 1 and Voyager 2. Weighing only 800 kgs each, they collected a wealth of scientific data and thousands of photographs of the four giant planets in our Solar System. After visiting Jupiter and Saturn, Voyager 1’s trajectory left the ecliptic plane in order to photograph Saturn’s moon Titan. This meant that Voyager 1 would not visit any other planets. However, Voyager 2 continued on to visit Uranus and Neptune. Still today, Voyager 2 is the only spacecraft to have visited these two “ice giants” and their moons.
Both Voyagers are still in operation and providing unprecedented data that engineers and scientists using today to understand space. Both are expected to last until 2020-2025, at which time their atomic battery life will no longer support their electrical systems.
Pioneer 10
Launched on March 2, 1972, Pioneer 10 was the first spacecraft to travel through the asteroid belt, and the first spacecraft to make direct observations and obtain close-up images of Jupiter. Pioneer 10 is now coasting silently through deep space (its last transmission was in 2003) toward the red star Aldebarran (the eye of Taurus the Bull), a journey of over 2 million years. Originally intended as a 21-month program, this 30-year mission has more than paid for itself with discoveries and science.
Mariner 10 was a robotic space probe launched on 3 November 1973 to fly by the planets Mercury and Venus. It was launched approximately 2 years after Mariner 9 and was the last spacecraft in the Mariner program (Mariner 11 and 12 were re-designated Voyager 1 and Voyager 2). The mission objectives were to measure Mercury’s environment, atmosphere, surface, and body characteristics and to make similar investigations of Venus. Secondary objectives were to perform experiments in the interplanetary medium and to obtain experience with a dual-planet gravity-assist mission.
During its flyby of Venus, Mariner 10 discovered evidence of rotating clouds and a very weak magnetic field.
Mariner 10 flew past Mercury three times in total. Owing to the geometry of its orbit — its orbital period was almost exactly twice Mercury’s — the same side of Mercury was sunlit each time, so it was only able to map 40-45% of Mercury’s surface, taking over 2800 photos. It revealed a more or less moon-like surface. It thus contributed enormously to our understanding of the planet, whose surface had not been successfully resolved through telescopic observation.
If you watch the moon, you’d notice that it rises in the east and sets in the west. This direction is called ‘prograde motion’. The stars, sun, and moon all follow the same prograde motion, meaning that they all move across the sky in the same direction.
This lecture series is from an astronomy course at Ohio State. It’s a 20-week college-level course, so don’t feel like you’ve got to do it all in one night! You’ll learn about the solar system, planets, and universe through a well-organized set of lectures that really brings astronomy, human history, and current technology together. This content is appropriate for advanced students and above.
Sound can change according to the speed at which it travels. Another word for sound speed is pitch. When the sound speed slows, the pitch lowers. With clarinet reeds, it’s high. Guitar strings can do both, as they are adjustable. If you look carefully, you can actually see the low pitch strings vibrate back and forth, but the high pitch strings move so quickly it’s hard to see. But you can detect the effects of both with your ears.
This is the experiment that all kids know about… if you haven’t done this one already, put it on your list of fun things to do. (See the tips & tricks at the bottom for further ideas!)
This experiment is just for advanced students. Ernst Florens Friedrich Chladni (1756-1827) is considered to be the ‘father of acoustics’. He was fascinated by vibrating things like plates and gases, and his experiments resulted in two new musical instruments to be developed.
Alexander Graham Bell developed the telegraph, microphone, and telephone back in the late 1800s. We'll be talking about electromagnetism in a later unit, but we're going to cover a few basics here so you can understand how loudspeakers transform an electrical signal into sound.
Have you ever torn apart something and then couldn’t figure out how to get it back together again so that it worked? Worse, you knew that if you had only taken a few moments to think about the problem or jot something down, you know it would have taken you far less time to figure it out?
This experiment is for Advanced Students. For ages, people have been hurling rocks, sticks, and other objects through the air. The trebuchet came around during the Middle Ages as a way to break through the massive defenses of castles and cities. It’s basically a gigantic sling that uses a lever arm to quickly speed up the rocks before letting go. A trebuchet is typically more accurate than a catapult, and won’t knock your kid’s teeth out while they try to load it.
When you warm up leftovers, have you ever wondered why the microwave heats the food and not the plate? (Well, some plates, anyway.) It has to do with the way microwaves work.
The atoms in a solid, as we mentioned before, are usually held close to one another and tightly together. Imagine a bunch of folks all stuck to one another with glue. Each person can wiggle and jiggle but they can’t really move anywhere.
Can we really make crystals out of soap? You bet! These crystals grow really fast, provided your solution is properly saturated. In only 12 hours, you should have sizable crystals sprouting up.
Density is basically how tightly packed atoms are. Mathematically, density is mass/volume. In other words, it is how heavy something is, divided by how much space it takes up. If you think about atoms as marbles (which we know they’re not from the last lessons but it’s a useful model), then something is more dense if its marbles are jammed close together.
This is a simple experiment that really shows the relationship of mass, volume, and density. You don't need anything fancy, just a piece of bread. If you do have a scale that can measure small masses (like a kitchen scale), bring it out, but it is not essential.
A gram of water (about a thimble of water) contains 1023 atoms. (That’s a ‘1’ with 23 zeros after it.) That means there are 1,000,000,000,000,000,000,000,000 atoms in a thimble of water! That’s more atoms than there are drops of water in all the lakes and rivers in the world.
