We just learned about how Specific Impulse measures how a rocket works.
Some of the first rockets that were made came from China over a thousand years ago, after the invention of gunpowder.
These were known as Fire Arrows.
At first people just had the idea to tie an explosive ball of gunpowder to the arrow that would blow up after the arrow was shot with a bow.
Later on someone figured out how to use the gunpowder as a solid propellant for the rocket in a wooden tube as the propellant tank, and use the burning of the gunpowder to thrust the arrow up higher and farther.
This animal is extinct now, but it was part of the ammonite family, which look a lot like the shelled nautilus, but are actually their own family in the world of animals.
These Parapuzosias would grow to be around 2 feet wide, but one person found pieces of an old shell showing one that was over 8 feet tall!
Another famous castle is Veste Coburg built in Coburg Germany around 1000 AD.
This castle was built up on a hill, and was added onto over and over again through the years as it became a more important place.
In the 1506 a man named Martin Luther had some different ideas about the way people should go to church and study their Bible.
This made some people very upset and they wanted to put him in jail, so he went into hiding at this castle for a while, and worked on writing the Bible in the German language, which had never been done before.
This castle stayed strong for some very big battles, and one time the people inside lasted for five months while people outside tried to fight them.
It is one of the biggest castles in Germany, at over 375,000 square feet of space inside!
Another of the seventy was Silas - Bishop of Corinth.
Silas was one of the people who went around with Paul and Timothy, helping to spread the word of God to people in other places.
The bible says that Silas was with Paul in the town of Philippi, after some people who didn't like Jesus had them throw into prison.
They were praying and singing hymns and an earthquake came and broke their chains and opened the door to the jail so they could get out.
When that happened the jailer thought they had escaped and thought he would be punished for it, but Paul and Silas did not leave the jail, but instead sat and talked with the jailer and helped him become a believer in Jesus.
Another part of rocket science is called the Specific Impulse.
This is a way for scientists to measure how fast a rocket moves along, combined with how fast it uses up it's fuel as the rocket engine is blasting off.
The rocket can only burn up so much fuel before it runs out, so the more thrust the rocket for every little drop of its fuel really matters!
Another type of cephalopod is the Giant Cuttlefish.
This is the largest cuttlefish in the world, and they live around the southern part of Australia.
They are very colorful and can change their whole body to white, red or yellow, and very bright or very dark to try and either get the attention of other cuttlefish, or to confuse the animals they are hunting.
They also can raise up little bumps on their skin to make themselves look either bumpy or smooth, so they can look like rocks, sand or seaweed.
The giant cuttlefish is so popular in Australia, that for a festival someone made a 42 foot long parade float shaped like a cuttlefish, named "Stobie the Disco Cuttlefish" that could move its arms, blink its eyes, and had flashing lights and dance music.
Usually the first baby teeth that people get are the Central Incisors.
Most babies start with two front bottom teeth, and then later the two front top teeth come in.
These incisors are made to be sharp and bite through things like carrots.
Another famous castle is Castel del Monte in Andria Apulia Italy, built in 1240 by Holy Roman Emperor Frederick II, .
This castle is very different because it is octagon shaped, with eight sides and eight towers.
Some people believe there used to be a large curtain wall going around the outside of the castle.
The castle wall is 82 feet high, and the sides of the octagon are 54 feet wide.
It is a little different that there is no moat and no drawbridge.
There are only 2 entrances, one fancy one in the front, and a simple one in the back for servants.
It is very famous in Italy, and is on the one cent Italian Euro coin.
We learned that a rocket has propellant in a tank, and an engine that burns up that propellant and pushes the burning fuel out the back of the rocket at the nozzle.
As the fuel is being burned and pushed out of the nozzle, the rocket is pushed along through the air.
That push is called THRUST.
Some rocket engines have a lot of thrust and make rockets go very fast, blasting off into outer space.
Others only have a little bit of thrust, but they are very careful about exactly how much thrust they make in the right direction, like for steering a rocket.
Scientists have to know exactly how much thrust a rocket will have, so they know how much propellant they need, and how big of a tank to use and the shape of the nozzle.
This octopus lives on the sea floor, and tries to look like other animals.
It can change it's body color, puff it's head up, wave its arms around or hold its body in a certain way to look like other animals.
Sometimes it will try and look like it's prey like a crab, so that it can sneak up on the crab and eat it before the crab even figures out there is a dangerous octopus nearby.
Other times it will try and look like a poisonous animal like a lionfish, so that predators that might attack the octopus will stay away and not try to eat it.
Theses octopuses have been seen trying to look like a lion fish, sea snake, flat fish, jelly fish, crab or even a sponge!
They are very smart animals, and will decide which animal to try and look like depending on which other animal they meet.
These smart cephalopods have been seen looking like up to 15 different animals!
Humans are usually born with no teeth, and around six months after they are born the teeth start to pop out!
We call these first teeth Baby Teeth, and they are also known as milk teeth, temporary teeth, primary teeth or deciduous teeth.
There are twenty baby teeth that come in, with ten on top and ten on bottom.
They usually start with the bottom middle ones, then the top middle and then next on the bottom and top until all twenty are in.
The baby teeth are very important, because they help keep the jaw strong and in the right place, and they are holding a place for the bigger adult teeth that come in later.
Another famous castle is Schwerin Castle in Schwerin Mecklenburg-Vorpommern Germany, built in 973 AD.
Germany.
As different rulers came and went in Germany, this castle was taken over by different people and used for things like military forts, schools, museums or palaces for royal people.
It is now where the state's parliament meets and works.
The castle has over 650 rooms, and is on an island in the middle of Lake Schwerin.
There is a legend of a good ghost named Petermännchen living in the castle, that sneaks around and unlocks doors at night, and will also scare away thieves or intruders.
Stories say that if soldiers guarding the castle fall asleep at night, the ghost will make noises to wake them up!
This type of squid lives in the cold deep part of the ocean, over 2,000 feet below the sea.
It is very cold and dark at this part of the ocean, and there is not a lot of oxygen or food to eat.
Even though they are called the vampire squid, they do not drink blood of other animals.
They eat waste that is floating in the water.
These vampire squids are also kind of like an octopus, so they are their own type of squid and octopus cephalopod called "Vampyromorphida".
Just like the cirroteuthis octopus that looks like it is wearing a skirt, these cephalopods have their arms all webbed together.
Inside their webbed area their arms all have little poky looking spikes called cirri on them.
They are not sharp, and the vampire squid uses them to help collect the garbage food that is floating around in the water.
If they get scared, they can light up their body with photophores that make them glow.
Mostly just at the tips of their arms and the top of their head, but their whole body can make light.
They can also spit out some glowing goo, and sometimes they flip their webbed skirt area inside out and wrap it around their head to try and scare off someone who is trying to eat them.
These cephalopods can have black skin with a red eye, or red skin with a blue eye, so you can see why someone thought they looked like a scary vampire squid!
But mostly they are just a harmless animal floating deep in the ocean eating garbage and trying not to get eaten by a bigger animal.
