Video transcript of Episode 12: Ping Pong Pick Up
On-screen text reads: "Do Try This at Home from the Institute of Physics. Episode 12: Ping Pong Pick Up"
Camera cuts to a medium shot of Melissa. She is sitting in front of a table and has placed a large, empty plastic bottle upside down over a ping pong ball. The top of the bottle has been removed. To the right of her in the corner of the screen is a thumbnail video of her competitor, James is about to place a similar empty drinks bottle over a ping pong ball. His children are watching avidly. We hear some game show music playing.
Melissa: “On your marks, get set, go!”
Camera cuts to a close up of Melissa. She has grabbed the bottom end of the bottle and started to move it in small, fast circles. Her competitor, James, starts moving his bottle in a similar way and as the ball starts spinning around inside the bottle, he lifts the bottle off the table.
Camera cuts to a medium shot of Melissa who is sitting in her living room. There’s a table in front of her and we can see a large two-litre, empty plastic bottle, some sticky tape, a marker pen, some scissors, a few ping pong balls and a mug.
Melissa: "Hello and welcome to Do Try This at Home brought to you by the Institute of Physics. We’re making these films for parents and carers across the UK and Ireland so that you can explore science together at home with your kids."
Camera cuts closer to Melissa.
"My name is Melissa, welcome back to my living room and today I have a gravity defying challenge for you and your family that I call Ping Pong Pick Up."
On-screen text reads: "Melissa Brobby, IOP Media Officer."
Camera cuts to a medium shot of Melissa so we can see the items on the table.
Melissa: "Each competitor is going to need an empty bottle, I’m using a two-litre fizzy pop bottle, some Sellotape, a marker pen, some ping pong balls, a pair of scissors, a bowl and something circular to draw around that’s wider than a ping pong ball but not as wide as your bottle."
As she speaks, Melissa rests her hand on a large, see-through empty drinks bottle, some Sellotape, a marker pen, three ping pong balls, a pair of scissors, a large ceramic mixing bowl and a large, ceramic mug.
Melissa: "To make your picker upper use your marker to draw a line around the curved part of the bottle."
Melissa turns the drinks bottle upside down and puts it in the mug. Using the mug as a template, she draws a circle on your bottle in marker pen around the curved part of the bottle. We hear her draw around the bottle. She then takes the bottle out again and we can see the line around the top of the bottle.
Melissa: “Now we’re going to have to make a hole in the bottle.
Melissa is holding the bottle horizontally. She uses her left hand to hold the bottle by the neck.
Melissa: "I’m going to use a pair of scissors to pierce it and adults should definitely do this part. Then carefully cut around the bottle and add little bits of sticky tape to cover any jagged edges to make it extra safe for little hands."
Camera cuts to a close-up shot of the bottle.
With her other hand Melissa pokes one of the scissor blades along the line she has drawn. She cuts around the bottle following the line until the top of the bottle has been removed. We see that there is still a small, curved lip at the top of the bottle.
Melissa then covers the jagged edge with pieces of sticky tape so that the “picker-upper” is safe to hold and use.
We hear a whooshing noise and the screen swipes to the right.
Camera cuts to a medium shot of Melissa. She shows the bottle, which is upside down, to the camera.
Melissa: "Take your bottle and place it over your ball and then start to spin your bottle in fast circular motions like this and once you’ve got your ball spinning lift your bottle up and then take your bottle over to your bowl and drop it in."
Melissa places one of the ping pong balls in front of her. She places the bottle on top of it and starts to move the bottle quickly in a circular motion. We can see the ping pong ball inside and around the inner wall of the bottle. We can hear the ping pong ball as it spins in the bottle and then when it bounces in the bowl.
Melissa: "My top tips are to spin the bottle quickly and lift the bottle vertically. The challenge here is to get the ball as quickly as possible from table to bowl. Then challenge your friends and family to a game of Ping Pong Pick Up."
As she speaks, we see Melissa place the bottle over another ping pong ball, spinning the ball very quickly as she lifts the bottle. We can hear the sound of the ball spinning again.
Melissa: "I’m going to call my friend James now. Hi James!"
Camera cuts to James who is waving at the camera with his two children. He is
James: "Hi Melissa!"
Camera cuts back to Melissa.
Camera cuts to James.
James: "I was born ready!"
Camera cuts to Melissa.
Melissa: "Okay... on your marks, get set, go!"
We hear game show music playing in the background. Melissa is now shown as a small image in the corner of the screen while James has now become the main image. Both competitors have picked up the ping pong ball with their bottle. We see them spinning the ping pong ball so that they can transfer it to the bottle without it falling out.
The first ping pong ball James picks up flies out of the bottle. We can hear it land.
Camera switches to Melissa as the main image. James is now the small image. Melissa has just dropped her second ping pong ball into the bowl. Another ping pong ball flies out of James’ bottle.
Camera switches to James as the main image. Another ping pong ball has dropped onto the floor. He is shaking his hands in frustration. At the same time Melissa has dropped the third ping pong ball into her mixing bowl.
Camera cuts to Melissa.
Melissa: "Ta dah!"
Camera cuts to James. We can hear him say: "Argh!"
Camera cut to his two children who facepalm. Then we see James who lightly shrugs his shoulders.
Melissa (voice-over): “Oh, keep up with the practice James.”
Camera cuts to Melissa.
Melissa: "So, what’s going on here and how can you explain it to your family? Well, the curved lip of our picker upper is the key."
Melissa picks up the bottle which is now upright and shows the curved lip to the camera.
Camera cuts to Melissa placing a cylindrical plastic container over a ping pong ball. She starts to move the bottle in a small circular motion.
Melissa: "You can prove it by using a container with straight sides like this. There’s no pickup."
As soon as the ball is spinning, Melissa picks up the container, but the ball runs away.
Camera cuts to a birds-eye shot of the container. We can see a ping pong ball inside it in the table. We see the ping pong ball spinning inside the container.
Melissa: "When we spin a ball inside the container it wants to fly out."
We hear a whooshing noise. The container has become an animated line drawing. There is a ball against the edge of the container.
Melissa (voice-over): “It pushes up against the wall of the container and the wall pushes back. It’s this push that makes the ball go round in a circle. The faster we make it go the bigger the force.”
We see an arrow pointing from the ping pong ball. Its points outwards to show that the ball wants to fly out of the container.
An arrow then appears on the ball to show the direction of opposing force. It points inwards to show that the ball is pushed back.
Camera zooms out to show the circumference of the bottle. The ball is spinning in a circle. It starts slowly at first. As the balls spins faster the arrow showing the opposing force lengthens to show that the force pushing the ball inwards is becoming larger.
Camera cuts to a new dynamic line drawing which shows the ball spinning but from a different angle. This time the ball is at the bottom of the diagram surrounded by the inside walls of a straight-sided container. The animation uses to arrows to shows that when the right side of the ball contacts the container wall, the opposing force is from the right to left, and vice versa.
Melissa (voice-over): "But to lift it up we need to overcome gravity, so we need an upward push. That’s why our curved surface works."
The straight-sided container is replaced with one that has sloped walls. This time the curved surface causes an upward push on the ball.
Melissa (voice-over): "It pushes in this direction along the diagonal which is equivalent to a force this big sideways and this big upwards"
A straight arrow appears on the ball which points diagonally upwards and inwards. That arrow is joined by two additional arrows which shows the force having two parts: the horizontal arrow pointing inwards, that makes the ball go around in a circle; and the vertical arrow pointing upwards, that balances the downward pull of gravity.
Melissa (voice-over): "And if we spin the ball quickly enough the upward part becomes big enough to balance gravity and that works with any round object inside the container that has a mouth narrower than its body."
All three arrows become longer, and then the vertical and diagonal arrows disappear, to leave the upwards arrow. We hear a whooshing noise, and the camera zooms out so we can see more of the animation. We now see the ball spinning in a circle in the container and that when the container is picked up, the ball is picked up too.
Camera cuts to a close-up of Melissa with a box of Maltesers. She places a Malteser in front of her, and then turns a wine glass upside down over it. She moves the glass in small circles and the Malteser spins around the inside of the glass in a circle. We hear the sound of the Malteser spinning in the glass as she picks it up.
Camera cuts to a medium shot of Melissa.
Melissa: "Don’t worry if you’re not totally sure about the science. As always have fun challenging your friends and family and then head over to our website for more information. Well, that’s it for this time so it’s goodbye from me and it’s goodbye from James."
Camera cuts to James who successfully manages to pick up a ping pong ball and drop it into a bowl. He turns to children and lifts his arms in victory. We hear him say: "Yay!" We hear the children laugh.
The image is replaced by some on-screen text which reads: "Do Try This at Home from the Institute of Physics. For instructions and more Do Try This at Home films visit iop.org/athome. These experiments have not been specifically safety tested for home use, but we believe them to be safe if the instructions are followed. Adult supervision is recommended as appropriate. All experiments are carried out at your own risk."