upside down glass water experiment

• 1 drinking glass
• 1 kitchen towel
• 1 rubber band

Short explanation

Long explanation.

• What happens if you change the kitchen towel to something else?
• What happens if you change the water to something else?
• What's the biggest container of water you can do this with?

Rainbow milk

Bouncing soap bubbles

Drops on a coin

Screaming dry ice

Dry ice in a balloon

Special: Dry ice color change

Dry ice smoking soap bubble snake

Dry ice giant crystal ball bubble

Dry ice in water

Gummy bear osmosis

Floating ping pong ball

Rotating Earth

Special: Colored fire

Special: Fire bubbles

Water cycle in a jar

Egg drop challenge

Taking the pulse

Orange candle

Glass bottle xylophone

Warped spacetime

Homemade rainbow

Water implosion

Warm and cold plates

Plastic bag kite

Tamed lightning

Yeast and a balloon

Forever boiling bottle

Moon on a pen

Moon in a box

Inexhaustible bottle

Crystal egg geode

Magic ice cut

Leaf pigments chromatography

Heavy smoke

Popsicle stick bridge

Micrometeorites

Special: Fire tornado

Special: Whoosh bottle

Dancing water marbles

Brownian motion

Flying static ring

Water thermometer

String telephone

Special: Dust explosion

Disappearing styrofoam

Special: Burning money

Special: Burning towel

Salt water purifier

Fish dissection

Hovering soap bubble

Homemade sailboat

Water mass meeting

Plastic bag and pencils

Water sucking bottle

Water sucking glass

Mentos and coke

Aristotle's illusion

Spinning spiral snake

Imploding soda can

Carbon dioxide extuingisher

Plastic bag parachute

Dental impression

Impact craters

Rolling static soda can

Static paper ghost

Color changing flower

Upside down glass

Shrinking chip bag

Solar system model

Strawberry DNA

Electric motor

Flashy electric motor

Toilet paper roll maraca

Cloud in a bottle 1

Cloud in a bottle 2

Balloon rocket

Water whistle

Homemade yogurt

Special: Screaming gummy bear

Homemade compass

Trash airplane

Wind-up spinner toy

Tea bag rocket

Balancing soda can

Lung volume test

Fireproof balloon

Baking powder popper

Expanding space

Straw propeller

Wooden cutlery

Levitating match

Human reflexes

Electromagnet

Soil layers

Straw potato

Straw rocket launcher

Traveling flame

Water bowls

Straw duck call

Solar eclipse

Silo of salt

Balloon skewer

Newspaper tower

Microwave light bulb

Heavy paper

Rubber chicken bone

Homemade marble run

Cartesian diver

Content of website.

Floating Water

Turn the glass over and nothing spills.

Print this Experiment

Is it really possible to fill a glass with water and turn it upside down without spilling? this clever science trick is a popular after-dinner science stunt, but make sure there’s a bowl close by to catch your mistakes.

Experiment Videos

Here's What You'll Need

Plastic cup or drinking glass, index card or old playing card, large bowl or sink to practice over, let's try it.

Before you get started, make sure the index card or playing card is large enough to completely cover the mouth of the glass. Fill the glass or plastic cup to the top with water.

Cover the cup with an old playing card, making sure that the card completely covers the mouth of the container.

Keep your hand on the card and turn the cup upside down. Hold the cup over the bowl just in case you accidentally spill.

The final step takes guts. Slowly take your hand away and the card will stay in place . . . and so should the water (keep your fingers crossed).

Don’t press your luck too far. Put your hand back on the card and return the cup to its upright position.

The temptation is just too great, and you know you’re going to do it again. Just make sure the card doesn’t become completely soaked and accidentally fall apart. This could be a huge surprise for everyone!

How Does It Work

The secret is right in front of your nose—it’s the air that we breathe. Air molecules in the atmosphere exert pressure on everything. Scientists know that at sea level air molecules in the atmosphere exert almost 15 pounds of pressure (okay, 14.7 pounds if you want to be exact) per square inch of surface area. Your body is used to feeling this kind of air pressure, so you don’t notice it.

When you first turn the cup upside down, the pressure of the air inside the cup and the air pressure outside the cup are equal. If you look closely, however, you’ll notice that just a little water leaks out between the card and the cup. This happens because the force of gravity naturally pulls down on the water. When some of the water escapes, this causes the volume of air (the space above the water inside the cup) to increase slightly. Even though the amount of air above the water stays the same, the volume occupied by the air is now greater and the air pressure inside the cup decreases. The pressure of the air outside the cup is now greater than the pressure inside the cup and the card stays in place. All of this is possible because the water creates an airtight seal between the rim of the cup and the card.

When the seal is broken (even a tiny bit), air enters into the cup, equalizes the pressure, and gravity pushes the water out. Poking a thumbtack-size hole in the cup allows air to seep into the cup from the outside. The pressure of the air molecules both inside and outside the cup stays the same, gravity takes over, the card falls, and the water spills. Watch out for the carpet!

Take It Further

Repeat the experiment but this time change the amount of water in the cup. Does it make any difference? What about if you switch the container? Will a wider cup hold the card better than a narrower cup? Does the temperature of the water have any effect on the water staying inside the cup?

Try the experiment using a paper cup or plastic cup but this time, using a thumbtack, poke a small hole in the bottom of the cup. What do you predict will happen if air is allowed to sneak into the cup?

Related Experiments

Mysterious Water Suspension

At first glance, you might think that you’ve seen this science demonstration attempted by a friend. A glass jar is filled with water and covered […]

Do Not Open Bottle

When you receive a package that says “DO NOT OPEN!” what do you want to do? Open it! It’s just human nature. Try this tempting […]

Drops on a Penny

You might think that you can’t fit many drops of water on the surface of a penny. Pennies are just so small! In the Drops […]

Browse more experiments by concept:

(Glass Or Cup) Upside Down Water Experiment : An Amazing Science Trick!

This upside down water experiment is one of these amazing Science activity that my son loves.

Who wouldn’t? It defies common sense, doesn’t it? How come the water doesn’t flow out of the glass or cup?

What in the name of Thor is happening here? Let’s find out.

surface tension, air pressure, adhesion, chemistry, water experiments

Cup Upside Down Water Experiment

You will need:

• cup or glass
• thick paper or old cards
• bowl (optional)
• food coloring (optional)

Doing this experiment in the Gally Kids Headquarters

So first thing we did was to pour water into the glass.

Well, actually, the first thing we did was to add color to the water. You don’t have to do this. But it looks better this way.

So here it is. Us pouring green water into the clear glass. We fill it to the brim.

Next, we get the bowl ready. This is totally not necessary. But you’ll thank me loads for it if the experiment fails (which might do — we find that some types of paper don’t work as well with this)

Once all these is set up, we put the thick card on top of the glass. And got ready to tip the glass upside down — this mainly meant making sure that the bowl was ready to catch the green water should this one fail.

Since it’s now all ready, it’s time to flip the glass upside down. This bit is easy because we’ve still got our hands on it.

Letting that hand go is a completely different matter. The first time we did, we were dubious (but thanks to that bowl, we weren’t too worried about it!)

You just have to trust yourself (and Science) to make this thing work.

And tadaa!!! it did!

We could even turn it up and down and up and down without the water pouring out.

Although eventually, it did! [which in itself was also fun!]

Look at this kids happy face with this amazing science experiment.

He says, “It’s easy to trick 5-year olds with this. They’ll say I’m a magician! But actually, it’s Science!”

So there you have it, the upside down cup water experiment.

If you want to do this amazing Science trick in your house (and you totally should!), here’s the easy to follow instructions.

Upside Down Water Experiment Steps:

• First, pour water into the glass. Fill it as much as you can.
• Next, get the bowl ready. Just in case the experiment doesn’t work the first time.
• Then, put the card on top of the glass. Put your hand on it and flip. This can be a bit daunting at first especially if you don’t have that bowl underneath. But just flip it and trust yourself.
• You will see a little bit of water seep out of the glass. Don’t let this scare you. Press your hand firmly and then….
• Just let go.
• And voila.. Water defying gravity. You can even flip it up and down and the card is still stuck to the glass.

Upside Down Water Explanation

This experiment from Physics Central gives a very detailed explanation of why this works.

Here’s my summary of it.

If you look closely at the glass, there is a little bit of space at the top. Because you quickly flipped the glass upside down, there was not enough time for the air molecules to go in into that space.

This means that there’s less  air molecules (therefore less air pressure) in the glass compared to the outside environment.

Why is this important?

Since the outside environment has higher air pressure, it’s stronger and is pushing that card to the glass/cup, making it stick to it.

The Second Reason

At the same time, water has surface tension and adhesion.

Surface tension makes water want to stick together (since they’re in that glass, their molecules want to stay together and not want to separate).

Adhesion is water’s characteristics to want to stick to materials. And there’s the card to stick to.

So basically, the water molecules don’t want to leave the glass and it’s also sticking to the card which is being pushed by the outside air pressure.

So if you consider these two things together working harmoniously with each other, you get upside down glass of water.

Upside Down Glass Of Water Experiment Video

You can also watch this experiment in video below. It’s from your Gally Kids Youtube Channel . Just a note – we regularly add cool science experiments, toy reviews and craft tutorials over there, so don’t forget to subscribe to get notified!

The Connecticut Science Center is currently CLOSED to the public due to public health concerns about COVID-19. For more information about COVID-19 and FAQs, please follow this link. Learn More

• Hartford, Connecticut
• Buy Tickets

Science At Play: Upside Down Water

• Andrew Fotta & Samantha Fotta
• February 10, 2021

One day I found my daughter Samantha drinking her juice in a very unusual way, the straw was not even in the cup of juice. I thought to myself, how is this possible and of course I found the answer in science. Keep watching to learn exactly how this trick works and how you can try it yourself at home.

Materials to Collect

• Clear straw
• Glass of water
• Thin plastic or oversized playing card that covers the mouth of the glass
• Bowl to catch any spills

Straw Trick:

• Put your straw into the water.
• Cover the top of the straw with your finger.
• Lift the straw out of the water.

No-Spill Cup:

• Cover the top of the glas with the rigid plastic or playing card.
• While holding the plastic in place, tip the glass upside down.
• Release the plastic and be amazed as the liquid does not spill out! 

What is the Science?

The air around us exerts pressure on us. At sea level, it pushes on everything at about 14.7 pounds per square inch. The reason we don’t feel it is because it pushes equally on all sides. The straw has solid sides, so the air can only affect the liquid in it through the openings in the top and bottom. When you pick up a straw from a drink, the air rushes into the top opening of the straw and pushes the liquid down into your cup. But if you put your finger over the top opening, air can longer push on the liquid from the top, leaving only the bottom for air to push on. Water molecules also like to “stick” together, this is called surface tension. (Ever see a liquid in a cup form a dome over the top of a glass?)  Between the air pushing on the liquid and the water molecules sticking together, the water will not fall out of the bottom of the straw. The same thing is happening with the upside down glass. Air pressure cannot push down on the water because the solid glass blocks it. The plastic covering the opening is being pushed up by the air pressure from below, holding it in place. This air pressure is heavier than the water in the glass and keeps the cover on and the water in the cup.

  Ask Your Young Scientists

While you are doing this experiment, ask your scientist:

• What happens when you release your finger from the straw while there is liquid in it?
• With water in the straw and your finger over one end, tip the straw so the opening is pointing up. What happens to the water? Why do you think this happens?
• How big of a glass can you get to be upside down with water in it? (provided you have a big enough cover.) 

More to Explore

Some other things to try:

• Try putting your finger over the straw BEFORE you put it in the water. What do you notice?
• Try different width straws. Does the size make a difference?
• How big of a glass can you get to be upside down?
• Try different types of containers. Find one with a narrow opening and compare to one with a larger opening. Do you see any difference? 
• Try placing an upside down cup in a bowl of water. What do you notice happening inside the cup? Does the water get inside?

Check out some of these activities from the Connecticut Science Center!

https://ctsciencecenter.org/blog/science-at-play-air-pressure-pranks/

https://ctsciencecenter.org/blog/science-sunday-experimenting-with-heat-and-air-pressure/

Find more air pressure experiments here!

https://www.asme.org/topics-resources/content/5-ways-to-demonstrate-air-pressure-to-children

We want to see what you try at home. Share your experiments with us on social media by using the #ScienceAtPlay and tagging @CTScienceCenter.

Andrew Fotta is a STEM educator at the Connecticut Science Center. He has currently holds a CT teaching certification for grades K-6, and has spent time in the classroom in nearly all grades, and taught middle school science. In addition to teaching classes for the Science Center, Andrew is also part of a team of educators currently creating new programs aligned with the new Next Generation Science Standards for grades PreK-9. Andrew is an avid photographer, who enjoys blending science and art in his work.

PLEASE SHARE THIS

You might also like.

Celebrating Black History Month Featuring Dr. Kizzmekia Corbett

Dear Science Podcast: How big is the moon?

Science Sunday: Eastern Box Turtles

How To Make An Upside Down Glass Fill With Water Science Experiment

How can water rise inside of an upside down glass? Let’s find out in this really cool science experiment!

a cup of water

an empty glass

food coloring

a tea light

safety googles

Directions:

1️⃣ Put on your safety goggles. 2️⃣ Mix a few drops of food coloring into the water. 3️⃣ Pour the water into the tray. 4️⃣ Put the unlit candle to float in the water. 5️⃣Light the candle. Adult supervision required. 6️⃣Place your empty glass over the lit candle. 7️⃣Observe as the water begins to rise slowly until the candle is out, then it rises fast.

Why does the water rise in an upside down glass?

According to  @stevespanglerscience , it’s because of air pressure! When the candle is lit and a glass is placed upside down, the air inside 1) becomes warm, 2) expands, and 3) escapes out the bottom of the glass. When the flame goes out, the remaining air in the glass cools (and takes up less space) and creates a lower air pressure inside of the glass compared to the outside of the glass. This leads to the air pressure wanting to be equalized which causes the air on the outside (and the water along with it) to be rushed in so that the air pressure is now equal in the inside and the outside.

Watch our video below:

Latest Posts:

Science in School

Fantastic feats: experimenting with water teach article.

Author(s): David Featonby

How can air hold the water in an upturned glass? Why does water stay in a bottle with a hole in its base? Find out with these entertaining experiments.

From their earliest years, children enjoy playing with water, and so do many older students. In this set of experiments, we look at the forces that are significant when dealing with water, demonstrating some basic science principles – and some surprising results. All the experiments are safe to do at home as well as at school, and require just simple household objects as the equipment, plus plenty of water.

Experiment 1: the upside-down glass

Many people have tried this experiment in some version, but can you work out what’s really going on?

• Straight-sided water glass
• Piece of thin card (large enough to cover the open end of the glass)
• Pour water into the glass until it is nearly full.
• Place the piece of card on top of the beaker.
• Turn the beaker upside down with one hand, holding the card in place with the other hand.
• Remove the hand holding the card (figure 1).
• Note what happens. Does the card fall off and the water fall out? Can you explain why not?

Surprisingly, when the glass is inverted, the card and the water remain in place. Why is this?

Let’s consider the forces on the card. These are:

• gravity, from the weight of the card itself (acting downwards)
• gravity, from the weight of the water pushing on the card (acting downwards)
• air pressure, which pushes on the outer surface of the glass and card, acting at 90 0 to the surface of the card (so producing an upward force on the card where this has just water above it).

So in this experiment, the force of air pressure pushes upwards on the card at the open end of the glass, opposing the force of gravity and keeping the water in the glass.

Extension: estimating the upward and downward forces

How do we know that the upward force of air pressure is enough to oppose the downward force gravity, to hold the water in the glass? We can estimate these forces quite easily.

The weight of the card is much less than that of the water, so to simplify we can ignore the weight of the card itself. This means that the downward gravitational force on the card is the weight of the water column

= h x A x ρ x g

where h is the height of the water column, A is the cross-sectional area of the glass, ρ  is the density of water (1 000 kg/m 3 ) and g is the acceleration due to gravity (approximately 10 m/s 2 ).

So if h is 10 cm (0.1 m) and A is approximately 25 cm 2 (0.0025 m 2 ), the downward force is approximately

0.1 x 0.0025  x 1000 x 10  = 2.5 N

For the upward force, this is the atmospheric pressure, P , multiplied by the area over which it acts, A.

Atmospheric pressure is approximately 100 000 Pa (pascals, or N/m 2 ).

So the upward force on card = P  x A

= 100 000 x 0.0025  = 250 N

So for a 10 cm water column, the upward force due to the atmosphere on the card far exceeds the downward force of gravity on the card due to the water.

We also need to recognize that the air above the water plays a significant role.  If this remained at atmospheric pressure, the weight of the water would be sufficient to remove the card, however as soon as the water exerts a downward pressure on the card, it reduces the pressure of this trapped air, which is sufficient to enable the upward atmospheric pressure on the card to support the water. A 1/100 change in volume of this air is sufficient to balance the water, i.e., the pressure reduces by 1/100 th  which is equivalent to the pressure of the water.

Further investigation

You can also think about the questions below, and perhaps carry out further experiments to answer some of them:

• Does this experiment work if the glass is completely full of water?
• How does the ratio of air to water change the experiment outcome?
• Would this experiment still work, no matter how tall the glass is?
• What other shaped containers (e.g., bottles) can be used?

Experiment 2: water’s invisible ‘skin’

In this experiment, we discover how cohesive forces within water act like an invisible ‘skin’ that can keep the liquid in an upturned cup – sometimes.

• Piece of thin woven nylon cloth (large enough to cover the open end of the cup)
• Elastic band
• Thin card (large enough to cover the open end of the cup)
• Cover the open end of the cup with the nylon cloth (figure 2, left).
• Pull the cloth tight, and secure it with the elastic band (or glue it to the cup around the rim).
• Pour water into the cup through the cloth, nearly filling it.
• Place the card over the nylon and the open end of the cup.
• Turn the cup upside down.
• Note what happens: the water should stay in the cup, as in experiment 1.
• Now carefully remove the card. Does the water flow out through the nylon cloth? If not, why? Water was poured in through the cloth, so why doesn’t it pour out again?
• To pour the water out turn the cup upright again quickly, then tip up the cup slowly while pressing a finger on the nylon (figure 2, right).

The reason why the water does not flow out through the very small holes in the nylon is because there are forces of cohesion between the molecules in the water. These forces make the surface of the water act like a ‘skin’ between the tiny holes in the nylon cloth. This effect is known as surface tension, and it is the same principle that keeps you dry under a woven nylon umbrella: there are tiny holes in the cloth, but the rain won’t get through due to the cohesive forces of surface tension between water molecules.

Further investigations

There are plenty more experiments you can do with surface tension and molecular cohesion. Perhaps look up ‘surface tension experiments’ on the internet and see what other activities you can find?

Here are two further simple experiments you can try.

Paperclip boat

Take a dish of clean water and a paper clip. Hold the paperclip in a strip of paper towel and lower it into the water. Then allow the paper to sink or carefully sink it with a toothpick. The paperclip will appear to float but is in fact being held by the surface tension of the water.

What else can you ‘float’ – for example, a ring pull from a drinks can? What happens to the paper clip if a drop of washing-up liquid is added to the water? How can you explain what you see?

This effect can also be used to make a ‘ soap boat ’.

Joined-up water jets

Take a clean empty drinks can, plastic cup, or bottle and make three small holes close together, near the base. Fill the can with water, and when three jets come out, use your fingers to try and join the jets together. You will be able to do this, because of the cohesive forces between water molecules.

Another fun experiment to illustrate cohesion is pouring water down a string .

Experiment 3: bottled water

These activities use a simple bottle of water to reveal some surprising effects due to surface tension and gravity. It’s a good idea to do them outdoors because water spillage is likely (see figure 3).

• Plastic bottle (250 ml) with screw cap
• Large needle or nail

Use the needle or nail to make one (or more) very small holes near the base of the plastic bottle by heating it over a flame (safely held) until it is hot enough to melt the plastic. In schools, this should be done by the teacher in advance of the experiment, for safely.

• For fun, you can add a label to the bottle saying ‘Do Not Open’ – and see if people ignore this.
• With the cap off, quickly fill the bottle with water, holding your finger over the hole, and then replace the cap.
• Hold the bottle still (or hand it to someone else) with the cap closed. What happens to the water?
• If the warning is ignored and the bottle cap is opened, what happens?

Once a container is sealed, water will only flow out of a small hole if that water can be replaced by air or more water. A bottle with one small hole can therefore hold water if the cap is sealed. Once the cap is unscrewed the water will flow out, due to the weight of the water. The hole needs to be small enough for the surface forces to hold the water.

Another interesting experiment to try with a full bottle of water with a hole near the base is: what happens when you throw the bottle up and catch it?

If you fill the bottle with water and hold it with the cap unscrewed for a few seconds (figure 4), the water will flow out of the hole.

Now throw the bottle up in the air (figure 5), and watch it carefully as it falls. Observe each part of its journey – on the way up, at the top of its flight, and on the way down.

When the water is in free fall (i.e. on the way down), water will cease to flow out of the bottle. This is because the water within the bottle becomes weightless relative to the bottle itself, as both the bottle and its contents are in free fall. Thus, in this situation the weight of the water does not force it out of the bottle.

This effect can also be demonstrated with a water-filled hollow tube (around 50 cm, with a diameter that can easily be covered by a finger). The bottom of the tube is covered with one hand while it is launched into the air, with this hand exerting the launching force and the other just supporting the tube. However, this can be a little tricky to demonstrate because it is essential that the hand covering the tube end is the last to let go when throwing the tube up and the first to contact the tube again on catching it, to avoid accelerating/decelerating the tube without the water column.

You can also try to answer these final questions:

• What happens to the water when the bottle is travelling upwards during the throw? Can you explain this?
• If you try to catch the bottle, what happens to the water? Can you explain this?
• What else can you throw in the air so that there is a change in what happens when it is in free fall, compared with when it is stationary? Hint: Think of toys or devices that work with gravity, e.g. where particles or moving parts or liquid fall through a gap.
• A more detailed version of the thrown water bottle experiment: Tsakmaki P, Koumaras P (2017)  When things don’t fall: the counter-intuitive physics of balanced forces . Science in School 39 :36–39
• Try a similar experiment to the paper cup and nylon cloth activity:  https://www.stevespanglerscience.com/lab/experiments/water-screen/
• Watch this video with more activities to try with your students using water:  https://www.youtube.com/watch?v=CCxbI1qRsWY&ab_channel=DrewtheScienceDude
• Learn how to make a soap boat:  https://www.youtube.com/watch?v=OU76wwmg9Hs
• Watch a video on the running water experiment:  https://www.youtube.com/watch?v=8nOU7jbRPPo&ab_channel=DrBoydTheChemist
• Read other Teach articles from the Fantastic Feats series:
• Featonby D (2017)  Fantastic feats.   Science in School 39 :45–47
• Featonby D (2018)  Further fantastic feats: falling and bouncing .  Science in School   43 :37–54
• Featonby D (2019)  Fantastic feats: magic with money .  Science in School   47 :46–50

David Featonby taught physics throughout his career in a large UK comprehensive school, and now shares his ideas across Europe through the organisation Science on Stage, of which he is a board member, helping to organize its activities. He has presented workshops in various European countries and written articles for both Science in School and Physics Education , including a regular series called What Happens Next? in the latter. David has a particular interest in making physics relevant to all ages through experiments that use everyday equipment.

The simple experiences shown in the article, easy to reproduce and using materials that are easy to find, allow students to approach the topics of surface tension and pressure in liquids. The author, also, by highlighting the “magic side” of some experiments, makes them more interesting and also suitable for the general public. The article offers the possibility to make interdisciplinary links to biology topics, such as pulmonary respiration (and how nature provides the alveoli with surfactants to decrease surface tension), capillarity in plants, or how the surface tension allows some insects to walk on the surface of the water

Maria Teresa Gallo, Math and science teacher, Italy

Download this article as a PDF

Share this article

Subscribe to our newsletter.

ScienceFunKids

Science Experiments for Kids

Upside down Glass of water without spilling

• April 14, 2021 April 28, 2021

The earth is surrounded by atmosphere. The atmosphere consists of a mixture of gases called atmospheric air. Atmospheric air exerts pressure (atmospheric) on each body inside it, which is due to the weight of the air.

• Glass of water
• Piece of Paper

Fill a glass with water and place a piece of paper on top of it. Press the paper slightly with your palm. Turn the glass upside down (preferably in a bowl). Notice that the water does not spill!!

Explanation:

Two forces are exerted on the paper, one pushes down the paper due to hydrostatic water pressure and one pushes it up due to air pressure. The paper does not fall and the water will not spill out since the air pressure is much higher than the hydrostatic.

Remove a coin from water without getting wet

SCIENCE 4 FUN

Water in Upside Down Glass

Things You Will Need

• Empty Glass
• sheet Cardboard (that covers the mouth of glass)
• Fill the glass with water completely.
• Take a flat sheet of cardboard and place it over the mouth of the glass.
• Hold the cardboard with the glass tightly, then quickly upside down the glass.
• Slowly take away your hand that is holding the cardboard.

If all goes correctly, then the cardboard will stick to the mouth of the glass. The water will not fall from it.

What is Happening?

So, you’re thinking what is happening here! It all happens due to the absence of air in the glass. As a result, the pressure of outside air is much greater than inside of the glass. So, outside is forcing the cardboard to stay in its place. Which in turn, keeps the water from falling.

• Try to use different kinds of paper sheets and use it in the place of the cardboard for hold the water. Observe which paper sheet is able to hold the water.
• Use glasses with the wide and narrow mouth, and find out which is easier for this experiment.

You Will Also Like

We apologize for the inconvenience...

To ensure we keep this website safe, please can you confirm you are a human by ticking the box below.

If you are unable to complete the above request please contact us using the below link, providing a screenshot of your experience.

https://ioppublishing.org/contacts/