[Intro]
Hey there!
Squeeks and I are just hanging out, building a blanket fort.
That’s right!
We built a fort...inside our fort!
I bet you’ve built a fort before, too.
If you use your imagination, you can come up with all kinds of creative ways to make
a space of your own, for reading, snacking and -- hiding!
You can use cushions, blankets, and even furniture.
But no matter how you build them, all forts have one really important thing in common;
they need forces to stay together.
You might remember that we’ve talked about forces before—they’re the pushes and pulls
that objects put on each other.
Forces are everywhere.
And experts called engineers are always studying forces, so they can design and build things
like skyscrapers and bridges.
So when you build your fort...
you’re thinking like an engineer!
Now, if you’re gonna become a successful fort builder, one of the forces you'll need
to get to know is called tension.
Tension is just another word for pulling something tight, so it’s a force that pulls rather
than pushes.
And if tension sounds familiar, it’s because we’ve talked about it before!
When an awesome SciShow Kids viewer wrote in to us to ask why bridges were so strong,
we learned that tension is one of the forces that help suspension bridges hold up the cars
and trucks that drive across them.
And that’s because the bridge is held up by cables…and the cables are pulled tight
by heavy anchors that are sunk deep into the ground on either side of the bridge.
When the cables are pulled, it creates tension, which holds up the bridge!
So!
How can you build a fort using the same force that holds up giant structures like the Golden
Gate Bridge?
Well, to make tension, you'll need something you can pull tight, like a sheet from the
linen closet.
Next, you can grab a couple of chairs, a few nice heavy books and then put the ends of
the sheet over the backs of the chairs.
Then you can put the books on each corner of the sheet, so it’s stretched tight.
The heavy books acts like anchors, pulling the corners of the sheet away from each other.
This stretches the sheet tight, and causes tension, just like the suspension bridge.
And now, you have a nifty roof for your fort!
But that’s just one way that you can use tension to build a fort.
Let’s try another design.
How about tying a string to a big, heavy, sturdy piece of furniture, like a bedpost?
Then you can pull the string tight, and tie the other end to something heavy, too.
Once you've done that, you can drape the sheet over the string, anchor the edges of the sheet
with your heavy books, and then you'll have a tent!
This tent-fort is actually a tension two-fer!
Because: We’ve used tension in two different places.
The string is pulled tight between the two pieces of furniture, and the sheet is being
pulled up by the string, and down by the weight of the books.
Without tension, that floppy sheet wouldn’t have any shape.
You could say: The force makes the fort!
All you'll need now is a flashlight and some snacks.
So whether you're in the mood to snuggle up with a book and a couple of cookies, or just
make a super-secret hideout, all you need is a sheet, something to hang it on, some
anchors, and your imagination.
Tension will do the rest.
How do you like to build your forts?
Have you made one that you’re really proud of?
Send us a picture!
Or ask us about anything that’s on your mind!
Just leave a comment below, or email us at kids@thescishow.com, and we'll see you next
time!