Can I really think of 10 ideas based on a roll of toilet paper? probably not but I'll have a go.

**1. Snatching a piece**

Have you ever noticed how, by pulling fast, you can snatch off a piece from a full roll but not an empty one? It's all to do with the force required to accelerate the roll. Try dropping a fixed mass a fixed distance on the free end.

*What is the relationship between the angular acceleration of the roll and the roll diameter?*

Knowledge of rotational inertia required.

**2. Rock and roll (1)**

Similar to the above but simpler. Just hang a mass (a rock?) on the free end and measure the angular acceleration.

*What is the relationship between the angular acceleration of the roll and the roll diameter?*

**3. Rock and roll (2)**

Similar to the above but keep the size of the roll constant and vary the mass.

*What is the relationship between the angular acceleration of the roll and the mass?*

**4. Rock and roll (3)**

This time vary the diameter of the cylinder used to hold the roll.

*What is the relationship between the angular acceleration of the roll and the diameter of the cylinder?*

Changing the cylinder diameter offsets the centre which changes the rotational inertia.

**5. Paper bridge (1)**

Make a suspension bridge between two points and hang masses on the middle until it breaks.

*What is the relationship between the force required to break the bridge and the length of paper?*

Assuming the paper always breaks under the same force the longer the paper the more weight it should support.

HALF WAY THERE

**6. Paper bridge (2)**

Make a suspension bridge between two points and hang masses on the middle until it breaks.

*What is the relationship between the vertical displacement of each sheet and its horizontal position?*

Photo analysis in GeoGebra or LoggerPro could be useful.

**7. Blowing in the wind (1)**

Hang a long streamer in a light wind.

*What is the relationship between the horizontal displacement and the distance from the top?*

Probably difficult to do but can be modelled in Algodoo. Again, photo analysis in GeoGebra or LoggerPro could be useful.

**8. Blowing in the wind (2)**

Attach a streamer to a long pole and run with it

*What is the relationship between the angle of the streamer and the velocity?*

**9. Andrex advert**

There used to be an advert involving a dog, soft, strong and very long. Unroll the paper down a long slope.

*What is the relationship between velocity and distance travelled?*

Ideal for an iterative model in Excel.

**10. Football hooligan**

Hold the free end and throw the roll.

*What is the relationship between the x and y displacement?*

EASY I've obviously been doing this job for too long.

WARNING Apart from no. 1 these are all untried and untested. They are not guaranteed to get anyone a 7 but I think I could with most of them.