Spark a conversation with this video showing water defying gravity. This activity is great for describing observations and applying ideas in unfamiliar contexts.
Run the activity
1. You’re going to watch a short video. The aim isn't to find right answers, it's to explore ideas and find out what they know.
- Do they know what might happen based on the image?
2. After you've watched the video, lead a discussion with your class:
- What surprised you about what you saw?
- Which forces are at play here?
- Why does the water not fall to the ground?
- Apart from water, what else is in the glass?
3. Ask the class to describe what they saw using only one word.
Gravity is the force that pulls things to the ground, so why does the water not fall to the ground when the glass is turned upside down? Air around us pushes in all directions – this is called air pressure. The air pushing up from under the card is strong enough to prevent the weight of the water from pushing the card down. You might also notice the small ‘pocket’ of air in the glass when it is tipped upside down. This pocket of air has a low pressure compared to the higher air pressure pushing against the card.
Take it further
Video credit: Wellcome