# collected by Ivo Hamers, Charlotta Barck and Vanessa van Engelen, with the help of the people of HST2002

1.   Swedish rocket:

Take an empty teabag. Put it vertically like a chimney. Take some matches. Light up the top of the teabag. The teabag will fly.

Physics: Convection.

2.         Singing cymbal:

Use a cymbal or metallic plate that can vibrate freely. Use a flash, for example from a camera, hold it close to the plate and flash. You will hear a low tone.

Physics: The moment of the photons are transferred in an inelastic collision to the atoms of the cymbal. This can also be used as an example of energy conversion.

3.         Kung Fu trick

Put two wine glasses on the table. Place a wooden rod ( approx. 1cm x 1 cm x 1m) with one needle at each end on the glasses, with the needles resting on the rim of the glasses. Take a sward and hit the middle of the rod, with high velocity. The rod will break but the glasses stay intact (hopefully)

Physics:  Inertia??

4.         Catching the ball:

Take a strip wood (or a ladder). Nail a plastic cup on to the strip. Place a ball on the strip, higher than the cup. Lift the wooden strip, so the ball is above the place where the cup was (look at the picture). Let the strip fall down to the ground. The ball will fall into the cup.

Physics: Inertia.

5.         Falling tower.

Take 15 to 20 wooden cubes. Build a high tower on a wooden strip. Incline the strip. The tower will fall, but not in a straight line.

Physics: The centre mass has to have an acceleration of 9,81 m/s2.

exp15.rm

6.         The lazy magnet

Take two aluminium tubes, a magnet (with a diameter smaller than the tubes) and a  piece of metal with the same dimensions as the magnet. Let the magnet and the piece of metal fall at the same time through the tubes. The magnet will come down later.

Physics: Lenz law.

7.         The thick magnet

Put a aluminium tube on a scale let a magnet (with a diameter smaller than the tube) fall through the tube. You will see that the weight increases.

Physics: Lenz law

8.         Christmas time

Put a sparkler in a drill and put the drill on. You see the sparklers forming a circle.

Physics: Central force.

9.         Balloon in prison:

Boil water. Put the water in a boiling flask and a balloon on top. Cool the water. The balloon will go in the flask. Ask the students how they can get the balloon out of the flask.

Physics: Heat the water, expansion of the gas.

Put 5000V on two copper wires, which are placed parallel and close to each other. Place a candle under the two wires. You will get a climbing spark.

Other version: Take two coat hangers and unwire them. Place them in a V-form (not touching each other) on a non-conducting block. Put 15000V on the wires again you will get a climbing spark.

Physics: convection, sparkjump.

11.       The circling paper-clip.

Put a cup at one end of a  two meter long thread    and attach a paper-clip at the other end.. Put a pencil under the thread near the cup. Let            the paper clip go. It will turn around the pen, getting faster and faster.

Physics: central force, moments of inertia

12.       The loudspeaker door:

Turn a music box on. Put it on the door. The sound will increase.

Physics: Resonance.

13.       Making music:

Take a straw and a pair of  scissors. Cut of the straw while blowing in it. You will hear different tones.

Physics: tones.

14.       Jumping ping pong ball:

Take two wine glasses and place them close together. Put a ping-pong ball in one of the glasses. Blow over the glass where the ball is in. The ping-pong ball will “fly” into the other glass.

Physics: Bernoulli

15.       Disappearing liquid:

Take 50 ml of ethanol and 50 ml of water. Put them together and you will have less than 100 ml. Approximately you’ll have 98%.

Model: Take 150 ml yellow peas and 150 ml rice. Put them together, you’ll have less than 300 ml.

Physics: Model

16        Flying plastic cups:

Glue the bottoms of two plastic cups together. Take a long  (0.5 m) rubber band. Wind the rubber band around the middle of the two cups. Pull the rubber band and shoot.

Physics: Moving objects

17.       The noisy pillow

Put a buzzer in a pillow. Throw the pillow around. You will hear the noise changing.

Physics: Doppler effect

18.       The laser-trapped beam

Take an empty plastic bottle of water (1,5 litter). Make a little hole in the middle of the bottle. Put the bottle under a tab so that the water can fall in it. Place the laser in front of the bottle so that the laser beam is trapped in the water stream.

Physics: Reflex ion

19.       Growing marsh mallows.

Take an empty wine bottle and put a marsh mellow in the bottle. Take a vacuum pump (the one they use for wine bottle is good). While pumping the air you will see the marsh mellows growing. Instead of marsh mellows you can use shave cream

Physics: gas laws.

20.       The magic skipping rope

Take long copper wire. Put the ends of the rope into the input of the oscilloscope. Two students have to take up the rode and the third student has to skip while the two other turns the rope.

Physics: electromagnetic induction.

21.       Dinnertime:

Put a glass, a bottle and a plate on a tablecloth. Take rapidly the tablecloth away. The glass, the bottle and the plate will not move.

Physics: inertia

22.       Catching the coin

Take a glass, put a piece of carton on top of it. In the middle of the carton you put a coin. With one finger tick you push the piece of carton of the glass. The coin will fall in the glass.

Physics: Inertia

23.       The cached water

Take a glass and fill full of water, so that the water flow over the border. Put a piece of carton on top of the glass. Turn the glass. The water will stay in the glass.

Physics: atmospheric pressure.

24.       Cola experiment

Take a bottle of coca cola light and of coca cola (normal). Fill a basket with water. Put the two coca cola bottles in the basket. The bottle with coca cola (normal) will sink and the bottle with coca cola light will float.

Physics: density

25.       Strong eggs

Take two boxes of six eggs. Open the boxes and go standing on the eggs. But support you by leaning on two chairs.

Physics: pressure

26.       Monorail

Build a kind of monorail and hang it on the ceiling. Build a train that hangs on this rail and eventually power it with a battery and a small e-motor.

Physics: forces, torque, speed, distances and time

27.  Monkey Ride

Like the monorail (26), but now don't build the whole monorail but just 1 meter of it. And then put a monocycle with very low point of gravity on it. And just for fun and the better looks: let a little monkey ride on it.

Physics: forces, center point of mass, torque

Take a tuning fork and after striking it you put the bottom of the fork to an ear of a student. The bones and chambers of his head will resonate and will amplify the sound.

Other version: You can do the same using a window, were you can demonstrate that more energy is lost and the sound is deadening more quickly.

Physics: sound

29.       Magnet competition

Give the pupils different kind of metal wires (1 meter long) and some different kind of screws and a battery (4,5 V). Let the pupils make the best kind of magnet they can.

They will then understand how an electromagnet works.

Pick up small sewing needles and see how many the pupils can pick up with their magnet.

Physics: magnetism

30.       Barbapapa (or Barbapappa in Swedish)

Take a piece of thin wood or cardboard and cut an arbitrary shape out of it. Make at least three holes in it, and hang the shape at each of the points. When the shape is at rest draw a vertical line from the hanging-point. Repeat this for every hole. The cross point of all the lines will be the center of mass for this Barbapapa.

Physics: center of mass, (torque)

31.       The Monkey Gun

Tilt a smooth table by a few centimeters. Use two marbles or steel balls. One is simply released from one top corner to roll down the table. The challenge for the students is to figure out how to release the other marble from the other top corner so that it strikes the first one before it reaches the bottom. They have to find a way that will let them strike the marble every time. (Obviously, they need to shoot it horizontally at the same moment that they release the first marble. The easiest way to do it is to lay a meter stick across the top of the table, set one marble, and start the other one rolling along the meter stick. Then lift the meter stick.)

Physics: To show that vertical acceleration is not affected by horizontal velocity

32.       Showing Moment of Inertia

Equipment: Two cans of some very solid food like tomato paste or puree, one of them as is, the other is emptied with both ends of the can removed. Also take two small balls of about the same diameter as the cans, one hollow and one solid. I find a ping pong ball is excellent for the hollow ball. Tilt a smooth table by one or two inches and put a cardboard box on a chair to catch the things as they roll off at the bottom. Line the cans and balls up across the top end, using a meter stick to hold them steady. Challenge the students to predict whether they will all roll down together, or if not, then which one will win the race down the table, which will be second, etc. Lift the meter stick.

Physics: To show that moments of inertia for rings, solid cylinders, hollow spheres, and solid balls are different

33.       Estimating the value of the Moment of Inertia

This follows the previous experiment. It depends on being able to set up a low friction sliding track. An Air Track or a small rolling cart is possible. What I like best is to use water on a table and slide an ice cube. This time, one of the rolling masses races the sliding mass. You can get quite a good value for moment of inertia by comparing how much the rolling mass is delayed relative to the sliding mass. I have tried this with two equal size cans of food, one with solid food, and the other with liquid food. It should work, because the liquid will mostly slide down the table, but I have never been able to make this work.

Physics: To get an estimate of the value of the moment of inertia

34.       Dancing ball

Take a straw, bend it to 90 degrees and place a small ball on one end (ping-pong or even a lighter one). Blow on the other end en the ball will lift off but remains in the air current.

Physics: Bernoulli

35.       Blowing ping-pong balls

Hang two ping-pong balls from the ceiling. The distance between them should be about 5 cm.  Then blow short but strongly between them.

Physics: Bernoulli

36.       Cheap refraction

Put a piece of paper on a cardboard plate. Put a rectangular prism on it and mark with a pencil where it is. Put two needles on a straight line with an angel between the prism and the straight line.

Look through the prism and put two other needles on a straight line witch coincide with the other needles.   Draw lines between the needles and you will have picture of how light travels through a rectangular prism.

Physics: optics

37.       Telephone

When you are discussing different wave types it is good to let the pupils make there own “plastic telephone”. Ask them how it works and when there are best conditions for it to work. You just need two plastic cups and a string.

Physics: Waves

38.       Traveling fluids

Take two glasses with flat edges and a piece of carton. Fill one glass, till the edge, with colored cold water. Put on top of the glass the piece of carton. Fill the other glass with warm water, also colored but in a different color. Put the glass filled, with cold water upside down on the glass filled with warm water. The warm water will go up and the cold water will come down.

Physics: convex ion

39.              The magic playing cards

Lay five playing cards on the table. Put your thumb on the first and push very hard. When you take your hand of the table the card will be there at your thumb. Put this card exactly on the following card end push again very hard. Now the two cards will stay at your thumb. Do the same with the other cards.

Physics: air pressure

40.       Falling student.

Take two empty cans, which are not damaged. Let a student stand on the empty cans. Now give a smash into one of the cans. The can will collapse.

Physics: structures, forces

41.       The bouncing glass tube

Take a glass tube with a very round side. Let it fall on the hard ground, so that the round side hits the ground. After it bounced pick it up, otherwise it will crash.

Physics: materials, elastics.

42.       Flying balloons

Blow up a balloon and let it fly. It’s path will be random. Now put a straw in the balloon and blow it up again. You will see that the balloon will fly in a straight line.

Physics: third Newton law

43.       Camera Obscura

Take a toilet paper roll and cover one end with transparency paper and the other end with just a normal piece of paper. Put a small hole in the last one. Point the hole at a flame of a candle and at the transparency paper you will see the flame up side down.

Physics: optics

44.       Car detection

Make a coil out of a cupper wire and connect it to an oscilloscope. Then pass this coil with an (5 kg) iron ball. The oscilloscope will detect the change of the magnetic field.

45.       Weightless

Take a bottle and make a hole down at the side. Fill the bottle with water. If you let the water flow out of it, you will see a parabolic curve. Go standing on a chair and let the bottle fall, there will be no water flowing out of the bottle.

Physics: Weightless

46.       Communicating balloons

Cut the bottom out of the bottle. Put a membrane on the bottom and one on the top. Pull at the membrane at the bottom and the balloon at the top will shrink. Push at the membrane at the bottom and the balloon at the top will grow.

47.       Moving Walls

## Comic disaster area

Breaking eggs:

Falling bottle of water:  exp11.rm