I thought we could head back to the Moon for an updated visit and marvel at our first off-world landing site.
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We see it in our skies regularly and we forget what a momentous achievement it was for humanity to land on the Moon. As exciting as the planned Mars missions are, there is still so much to learn about our nearest neighbour.
Did you know?
The Moon was probably formed when an object about the size of Mars collided with the Earth a long time ago. The debris from that collision formed what we now know as the Moon.
Our rocky satellite orbits the Earth at a distance of roughly 384 thousand kilometers.
It takes the Moon about 27 days to orbit the Earth. This is also about the length of a lunar day so we only ever see one side of the Moon from Earth.
It has a very weak atmosphere called an exosphere. It is not enough to support human life so visitors to the Moon need to wear spacesuits.
The Moon’s gravity is about 0.16 of the Earth’s gravity so objects on the lunar surface weigh about a sixteenth of what they would weigh on Earth.
The mission to the Moon captivated the world. You can get a sense of how people must have felt as the astronauts headed to the Moon and eventually landed on the lunar surface from this CBS footage of that momentous day:
We’re so accustomed to seeing high quality images and video footage of modern space exploration that it’s easy to forget that the technology back then was not nearly as advanced. We’ve certainly come a long way since then.
What does the Moon look like?
Thanks to NASA’s Lunar Reconnaissance Orbiter mission, we have some incredible footage. Here are two videos of both hemispheres of the Moon, including the side we don’t see from Earth.
This video footage shows the Moon’s position throughout 2017 with a lot of useful data that includes the Sun’s relative position, the Earth’s relative position and the phases of the Moon in tremendous detail.
This egg experiment involves creating a partial vacuum in a bottle that sucks a boiled egg into the bottle. The video is in Hebrew but you can see how it works.
בנסוי זה, בישלנו ביצה ויצרנו ואקום בבקבוק באמצעות נר. הוואקום מצץ את הביצה לתוך הבקבוק.
The idea is to use the candle to create a vacuum in the bottle. The reason this works is because the flame consumes the available oxygen in the bottle, creating a partial vacuum.
What you need for the egg experiment
You can probably find the items you need to run this experiment at home. Make sure you ask an adult to help you, though. You need:
A hard-boiled egg (with the shell peeled off);
A bottle with a neck slightly narrower than the egg;
A candle and matches (always be careful with matches – as a grown-up to help you); and
A clear space to do the experiment, away from anything that could catch fire.
How this experiment works
If you seal the lip of the bottle with the egg, you essentially seal the bottle. The flame will extinguish when there is no more oxygen to keep it burning and the resulting partial vacuum should suck the egg in.
What happens is that the air pressure inside the bottle drops much lower than the air pressure outside the bottle. The air pressure outside the bottle basically pushes on the egg and the lower air pressure inside the bottle practically sucks it in.
The effect of the higher pressure outside and the lower pressure inside results in the egg being sucked inside the bottle even though it is a little too big to fit without squeezing it in.
I came across this fantastic video of popping corn in slow motion from Warped Perception and had to share it with you.
So, how does popcorn actually pop?
First of all, there are a few types of corn that are grown. But only one kind can be popped. Popcorn.
And the reason that popcorn can be popped is that the outer layer, the hull, is thicker than any other type of corn. This comes in handy when the kernel is heated up.
You see, each kernel of corn has a small amount of water inside as well as a little blob of starch. When the water is heated up it turns into steam. Super heated steam. The steam mixes with the starch and changes it into a gel like substance.
Now the steam continues to heat up and expand, this causes pressure on the hull of the corn kernel. Since the popcorn hull is thick, it contains the heat for a slightly longer time than other corn, giving the starch time to form into that gel like substance.
Once the pressure gets too high, the hull bursts open and the starchy gel expands outwards, cooling as it goes, forming the puffy, yummy substance we love to eat.
Popcorn can jump up to 3 feet/1 meter into the air.
There are two types of popped popcorn, Snowflake and Mushroom shaped.
The oldest ear of popcorn was found in a bat cave in Mexico in 1948. It is believed to be over 5,000 years old.
A kernel will pop when it reaches a temperature of 175 degrees Celsius.
Popping popcorn is one of the most popular uses for microwaves.
The Biodiversity Heritage Library has a wonderful collection of resources about our shared biodiversity online. What is “biodiversity”? Wikipedia explains it as follows:
Biodiversity, a contraction of “biological diversity,” generally refers to the variety and variability of life on Earth. One of the most widely used definitions defines it in terms of the variability within species, between species and between ecosystems. It is a measure of the variety of organisms present in different ecosystems.
The goal of the Biodiversity Heritage Library is to improve “research methodology by collaboratively making biodiversity literature openly available to the world as part of a global biodiversity community”.
It is a remarkable resource, especially for school projects and for all you science geeks. One of the best parts of the Library is its extensive Flickr collection which has an enormous collection of scans and imagery.
The Library “serves as the foundational literature component of the Encyclopedia of Life” which you can find here. What is the Encyclopedia of Life?
Our knowledge of the many life-forms on Earth – of animals, plants, fungi, protists and bacteria – is scattered around the world in books, journals, databases, websites, specimen collections, and in the minds of people everywhere. Imagine what it would mean if this information could be gathered together and made available to everyone – anywhere – at a moment’s notice.
To increase awareness and understanding of living nature through an Encyclopedia of Life that gathers, generates, and shares knowledge in an open, freely accessible and trusted digital resource.
Between the Library and the EOL, these are wonderful biodiversity resources. Definitely worth bookmarking for all those school projects and personal exploration. I’ve added both sites to our Sources page.
NASA publishes a large collection of photos and videos of our planet as seen from the International Space Station. They offer a truly spectacular view of our home.
What really stands out, particularly when you watch the videos, is that you don’t see borders and the many differences that divide us. Instead, what you see is the one, beautiful planet that we all share.
A wonderful example of this is astronaut Jeff Williams’ video of the Earth as he passed overhead during a recent visit to the International Space Station. This video, titled “Jeff’s Earth” is mesmerizing on a big HD TV:
When you drop a piece of molten glass into cold water, the result is a tadpole shaped piece of extremely hard glass.
Well, at least the head of the drop is very strong. The tail is actually quite delicate.
The reason Prince Rupert’s Drops are so strong is that the outer layer of glass hardens almost straight away, while the inside takes a bit longer. When hot glass cools down (and this happens with water turning into ice too), the glass shrinks. This means that the inside of the glass drop is cooling down and shrinking but the outside is already cold and hard so the glass pulls towards the centre of the drop and makes it really, really strong inside.
If you dropped a feather and a bowling ball at the same time, which would hit the ground first? You would probably say that the bowling ball would hit the ground first, right? After all, a bowling ball is so much heavier.
It turns out that the relative weight of the objects doesn’t make a difference to which object will hit the ground first, as strange as that may sound.
One of the parents in our class chat group shared this terrific video from the BBC that explains what really makes a difference and, surprisingly, that a bowling ball and a feather will hit the ground at the same time under the right conditions:
So, as you can see, the factor that makes the difference in normal conditions isn’t the objects’ weight, it’s air resistance! When you remove the air, both objects fall at the same rate and hit the ground at the same time.