Science for Year 7-9
Welcome to How Science Works
This website looks at how scientists find answers to questions that look impossible to answer, such as …
What do you see when you swallow a Pill Camera? (find out here)
Can a Professor of Optical Illusions totally baffle your brain? (decide for yourself here).
And lots more too – see the list of stories in the menu on the right.
Over-excited Fruit captured on Video
And now, to get things started, we present a scientific mystery for you to solve. Play the video and then see if you can explain why the raisins dance.
How does your answer compare with ours? Here’s what we think …
If you watch each raisin carefully when it gets to the surface, you’ll see that it twists over before sinking. It’s almost as if the raisin is resting on a float which flips it over …
So now we can explain what’s happening. As the raisins fall, they become covered in bubbles. The bubbles are carbon dioxide gas which is what gives the lemonade its fizz. The bubbles form and cluster onto the raisins and carry them to the surface. But once a raisin reaches the surface, the bubbles can escape. The raisin is flipped over becasue of the bubbles that are still on its underside. Now the last of the bubbles escape and the raisin falls! Is that what you said too?