Relativity Science Trail
You and your colleagues are going to become science detectives to investigate what the latest science news story is all about.
You can find the news story on the web. Have a quick glance now, if you're near a computer, just to get the flavour. You can spend more time on it later. 
Right now you're going to follow a trail to hunt for clues to the real science behind the story. You will work in groups to search for exhibits that have science secrets to tell you. 
Try not to get lost, but don't worry if you do. Glasgow Science Centre is a big place, but friendly. 
If you're not sure about something, just ask anyone in a Science Centre T-shirt. They will point you in the right direction.
 
Here's how it works
Each member of the group has a particular job, besides talking things over with the rest of the group and finding clues. These jobs are: 
The facilitator: makes sure everyone gets a chance to play with the exhibit and to offer an opinion when answering the questions.
The navigator: leads the group in the search for the right exhibits; reads and explains the instructions at each exhibit to the other group members.
The recorder: writes down the group's answers to the questions at each exhibit.
The reporter: takes part in all the activities and gives an oral report back in class.

On the science trail
For each leg of the trail you get the name of an exhibit at the Science Centre and its photograph. You are given two questions for each exhibit. 
To answer these you will need to play with the exhibit, try things out, see what it can tell you. You should take turns and chat among yourselves. 
The facilitator will make sure everyone gets a chance to try the exhibit and share their thoughts. He or she should aim to get answers that the whole group can accept. 
The first question on each leg is about what you find when you try the exhibit. The second question is usually a word missing from a sentence.
Before starting, please take a glance below at what the news story is about and the puzzle the science trail will help you to solve.
Happy detecting.
News: Thumbs up to Einstein

The latest news is about two strange stars in orbit around each other, way out in space. 
It's about what these tell us about general relativity, the best theory we have about space, time and matter.
Albert Einstein devised the theory of relativity over a period of ten years almost a hundred years ago. He came here to Glasgow some time later and gave a talk about it at Glasgow University. 
Through the Glasgow Science Centre windows you can see Glasgow University on the skyline:
Bute Hall, where Einstein gave his lecture, is in the building below that tall spire.
The puzzle
What is the theory of relativity all about?
Are you ready to go looking for clues? 
Here's the first exhibit you should try to find:
Plummeting plumage

Once you've found this exhibit, have a play with it. The navigator should read the instructions and explain them to the group. Pay particular attention to what happens when the air has been removed from the tube. 
The facilitator should make sure everyone in the group has a go and gets a chance to say what they see. Then as a group decide on the answer to this first question.
1. When the air is out of the tube, does the stone or the feather fall faster?
The recorder should write the answer here:

Once you've got an answer everyone can accept, take a look at this sentence and decide on the missing word. Each dash is one letter and we've given you the first letter to get you started.
2. When there is no air to slow things down, everything f _ _ _ _ towards the ground at the same rate.
Now the navigator should lead the group in a search for the next exhibit on the trail. This one is:
Sink or float
It looks like this:

Or when you're closer like this:

The navigator should read what to do with this exhibit and explain to the rest of the group. Once again everyone should have a go before trying to answer the questions.
3. When you follow the instructions on the twirling triangle, which ball moves the fastest - the left, middle or right?
Once you have an answer everyone can accept, the recorder should write the answer here:

Now complete this sentence using a word you can see at the exhibit:
4. Either the balls or the liquids have different weights for their size. Scientists say they have a different d _ _ _ _ _ _.
The next exhibit you are looking for is called:
In a spin

Take your time with this one and make sure everyone gets a turn. There are lots of ways you can move the wheel when it's spinning. But there is a pattern to what happens to the platform that you stand on when you do. 
Take turns to move the wheel so that it is spinning clockwise when you look down at it. Then try again with it spinning anti-clockwise. 
Here are your two questions: 
5. As you look down, in which direction does the platform spin when you make the wheel spin anti-clockwise? 
The recorder should write the group's answer here:

Now complete this sentence. 
6. If a wheel is _ _ _ _ _ _ _ _ really fast it is quite difficult to change its direction.

For the next exhibit on the relativity science trail you need to watch closely and stay on your feet. It's called
Points of view

Again the facilitator should make sure everyone takes a turn and the navigator should read and explain the instructions. You each have to stand on the roundabout and roll the ball from one white spot to the other. And you also have to stand beside the roundabout and watch its path as someone else rolls the ball.
Here's your first question for this exhibit:
7. When you try to roll the ball slowly from one white spot to the other, roughly how far do you miss by?

The recorder should write the group's answer here:

Now complete this sentence:
8. When I'm on the roundabout the path of the ball looks curved. But when I'm off the roundabout and someone else rolls the ball, its path is a _ _ _ _ _ _ _ _ line.

For the last exhibit of this science trail we do something slightly different. We give you a word before you start. The word is orbit
Gravity well
An orbit is a path that something follows for a very long time. Satellites have orbits around the Earth. The Earth has an orbit round the Sun. The twin pulsars have orbits around each other. 
Think about orbits in this exhibit as you take turns to roll the balls. 
Have a few practice rolls. If you throw too fast the ball jumps out. Too slow and it gets swallowed quickly. You'll soon get the hang of it.
Work together and take turns. Here's your first question:
9. What is the most number of times anyone in your group can make the ball go completely around before it disappears down the hole in the middle?
The recorder should write the group's answer here:

Now complete this sentence:
10. The only thing stopping a ball from having an orbit (a path that goes round for a very, very long time) is the force of f _ _ _ _ _ _ _ between the ball and the black plastic. 

That was the last exhibit, but the trail is not quite over yet. You should find a quiet corner so you can sit as a group and take a look at this final part.
Falling feathers again

You are going to find the final thing we tell you quite hard to believe.
It doesn't look it, but Plummeting Plumage is the most important experiment on this science trail. In fact it's the most important experiment at Glasgow Science Centre.
Actually it might be the most important experiment ever, anywhere. In the history of the world.
We've got to be kidding, right? It's just a big grey box with a plastic tube and stuff.
Surely this is nobody's most important experiment ever?
Well, yes it could be.

Words of wisdom
If you don't believe us, will you believe Albert Einstein?

Here's what Einstein told his audience at Glasgow University on 20 June 1933 about the results of the vacuum drop experiment - that everything falls towards the ground at the same rate:
"I wondered how this law could exist and believed that it held the key of the understanding of inertia and gravitation."
This one experiment made Einstein think deeply about gravity, forces and points of view.
It gave him a whole new way of looking at space and time.
It led him in the end to general relativity.

Solving the Puzzle
You have now finished this part of the relativity science trail. You have gathered a number of important clues to what the latest news story is all about. 
Back in class, you should work together as a group and chat with your reporter about what he or she is going to include in the talk to the class. 
You might want to mention these sorts of things: what was the hardest part of the trail, what was the most fun, what surprised you, what did you learn, what would like to know more about. 
It's really up to you.
Back in class or at home you can also take a look at Solving the puzzle to see how the clues you have found fit together and how they help solve the big puzzle. Can you remember what that was?
What is the theory of relativity all about?
You can also read a few more words from Albert Einstein himself when he came to Glasgow University.
Have a look too, when you've time, at the Twin pulsar news story to see how scientists have been testing general relativity, using two strange stars a long way from Earth.
Try to spot all the places where your science-trail clues put in an appearance.
Checking your answers
You have now finished the relativity science trail. You can check your answers yourselves on the web at Solving the puzzle , if you can find a handy computer with an internet connection – or Glasgow Science Centre will give you the answers.
How many did you get?
If you got them all, well done. You are first-class science detectives.

End of the trail?

So where do you go from here? Does the science trail end at Glasgow Science Centre? 
It doesn't have to. 
Some of you will become scientists one day. Maybe you'll devise a new test of general relativity or even a whole new theory of space, time and gravitation. Why not?
So what exactly is a scientist? 
One answer is that it's someone who's been to university to study physics, chemistry, biology or astronomy, and now does science for a living. 
A simpler answer is this: 
A scientist is someone who asks questions and keeps on looking for answers.