In this portion of the lab, you will test these three. Surface tension in water describes a condition where the surface of water that is in contact with air acts like a thin elastic sheet. This activity can be completed as a teacher demonstration or a student lab. Use pennies, soap, and a pipette to conduct a lab on the surface tension of water. Using a dropper bottle containing only water, count the number of drops of water that you can balance on top of a penny. Sep 25, 2017 3 use an eyedropper or pipette to draw water and, carefully, drop individual drops of water onto the flat surface of the penny. On the other hand, adding soap to the water interrupts the attraction between water molecules and greatly.
What is the independent variable, the dependent variable, and the control group. Measuring surface tension of water with a penny background conclusion water molecules h2o consist of 2 hydrogen atoms and 1 oxygen atom. We added an extra dimension to this classic lightningfast science experiment by comparing how many drops of water. As drops of water are added onto a penny, the adhesive force between the water and the penny keeps the water from falling off. Surface tension is the name we give to the cohesion of water molecules at the. This lab will look at the way that water sticks to itself to make a rounded shape, the way that. This shows inconsistent technique in creating the drops. Soap a surfactant will then be added to the water to test if this changes how many drops can be held on the penny.
When plain water is dropped on a penny, water molecules strongly attract one another and the resulting surface tension is high. Soap a surfactant will then be added to the water to test. Final surface tension student the young scientist program. Cohesion causes the surface of the water to have tension and tests can be done to measure the relative tension of different aqueous solutions. This is observed by the bubblelike shape formed by the water as more drops are added to the pennys surface. They experiment with additives to their best soap and water recipes to increase the strength or longevity of the bubbles. Observe surface tension by seeing how many drops of water can fit on a penny. The result of this expirement proved my hypothesis was correct because the pennies did hold as much water as possible until there was way too much water on the penny and the mass of the water grew greater then. In this portion of the lab, you will test these three properties and apply them to the concept of capillary action.
Be able to define surface tension, covalent bond, and cohesion. This is why the water can stack up into a large bead on top of the penny. Student teams first measure this property, and then use this measurement to determine the best soap solution for making bubbles. Understanding the science behind water surface tension is important. The instructions were designed for an intro vocational biology class that only meets for a semester. Surface tension also affects many construction materials, so civil engineers consider the surface tension of water when incorporating wooden beams into a buildings design. I am really bad at sketching so i am doing a written description first liquid water. I saw abraham lincoln bigger than before i started the activity.
Using water to attach two materials is often convenient, noncorrosive, readily available, transparent, and is easily undone. Youll probably be surprised by the number of drops you get on there. The science of water student materials contents the science of water lab activities. Surface tension can be measured and observed by dropping water drop by drop onto a penny. Have you ever wondered how many drops of water can fit on a penny. This cohesion property results in surface tension because water molecules at the surface of the water puddle attract more to one other than they do to the air molecules above them, they cling together and form a dome shape on the coin. Once the water has reached the edge, you begin to see a bubble or dome of water forming on top of the penny. Use the eye dropper to drop water on the penny, one drop at a time. This will come at the front of the lab, but should be the last thing written. I explain that in the days lab, the students will be adding drops of water to a penny using an eye dropper. In this portion of the lab you will determine which liquid has the highest surface tension. Sketch the side view of the penny just before the liquid spills over.
In some cases, you likewise complete not discover the declaration. When there is contact between the surfaces of two liquids like water and oil, it is called interface. Count each drop until the water begins to spill over the sides of the penny. Get down and get a side view of what the water on top of the penny looks like when it has the most water it can hold on top of it. Water molecules are cohesive they stick to each other because of the hydrogen bonds formed between them. This means you need to reduce the surface tension of water. In this physics lab, we will be exploring a property of water known as surface tension. Learn about the surface tension of water by dropping small amounts of water onto a penny and watching it form a bubble. Things that reduce surface tension are called surfactants. When we know about surface tension we can predict how water will behave when we use it in lots of different situations. Extension activity conduct the cup and penny surface tension activity with a variety of liquids including milk, soda, juice, and soapy water. Properties of water surface tension, cohesion and adhesion. An exploration of surface tension background and key concepts when water is gently dropped onto a flat surface like a penny, it stays together, forming a small drop, rather than running off the penny.
We added an extra dimension to this classic lightningfast science experiment by comparing how many drops of water fit onto each. Properties of water surface tension, cohesion and adhesion surface tension the force that acts on the particles at the surface of the material what causes the surface portion of liquid to be attracted to another surface like another portion of liquid adhesion the tendency of water to stick to other substances. Measure surface tension with a penny scientific american. The surface tension of water allows objects of greater density to be supported on the surface of the water. Experiment kinetic energy adhesion, cohesion, surface. Stemonstrations classroom connections surface tension. In this weeks family science activity, explore the way soap decreases the surface tension of water by testing with water droplets on a penny. Welcome to episode four, season three of science at home. Record the temperature in celsius table 1 once you pour the water into the beaker. Measuring surface tension of water with a penny prezi. Successfully get the least number of drops on a penny.
When the surface area of the fiqpufd is increased, lifting a wire ring out of the liquid for exarpfe. The attraction of water molecules to other substances, like soil or glass, is called adhesion. The cohesion and surface tension of water becomes apparent when the drops of water you add reach the edge. It helps us get our clothes clean, our glasses shiny and even makes our daily newspapers easier to read. What is the independent variable for the drops on a penny. In this project, you will put droplets of water on a penny, like in figure 1. Examine the penny and consider how many water drops you think will fit on the. The cohesion and surface tension of water becomes apparent when the drops of water you add to the penny reach the pennys edge. A water spider can sit on top of pond water because its weight isnt more. Obtain two pennies, 2 pippettes, and a beaker of tap water and some paper. Each section of the activity correlates to scientific processes that are discussed in their textbook. Liquids stick together teacher version in this lab you will learn about properties of liquids, specifically cohesion, adhesion, and surface tension. This is due to surface tension, which results from water.
These observations can be attributed to the high surface tension of water. Place your penny on a flat, level surface that can get a little wet, such as a kitchen counter. The higher the surface tension of the water, the bigger a droplet you can make before it breaks and flows over the edges of the penny. Students extend their understanding of surface tension by exploring the realworld engineering problem of deciding what makes a good soap bubble. These 2 elements hold together by sharing electrons which is called a covalent bond. I used the same penny and dropper through the experiment. Award less points if use significantly fewer than 20 drops and stop the investigation. In this experiment, you will visualize the surface tension of water by dropping water onto a penny with an eyedropper.
Measuring surface tension of water with a penny science buddies project idea measure surface tension with a penny science activity at scientific american. In this episode we add pennies into a full glass of water to show how surface tension will create a convex dome of water. Repeat the experiment as many times as you want, or take it further by testing. Count the number of drops until the water spills over the edge of. In the drops on a penny experiment, though, youll experience surface tension and. Jul 31, 2015 in visual terms, surface tension looks as if the liquid is covered by a thin, tautmembrane. The bubble shape is a result of the water molecules clinging to one another in an optimal shape just like. When water molecules hold onto each other like this and form a skin it is called surface tension. Find out for yourself, defy gravity, and show your students some magic by performing the coin and water experiment. Water molecules at the surface are pulled from both sides and experience surface tension. Compare the data to see which liquid has the highest surface tension. Builds social and critical thinking skills enhances effective com. Water piled on top of a penny showing surface tension caused by the cohesive property of water.
Fun and easy lab for students to follow the scientific method to contrast the number of drops of soapydistilled water that will fit on a penny. These principles will be demonstrated by adding drops of different liquids to pennies to determine the strength of molecular attraction. Surface tension is strong enough to support insects that crawl across the water s surface, like water striders gerridae. Sep 01, 2018 this lab was modified from the penny lab to focus more on the properties of water and how surface tension is important for aquatic organisms like the water strider. Surface tension add the definition of surface tension and examples in your notes fig. The purpose of this lab is to investigate the property of the surface tension of water. So i had to do a lab this week where we had to see how much distilled water,deterhent solution, sodium carbonate solution, and sodium chloride solution would fit on the surface of a penny.
Download file pdf water drop on a penny lab water drop on a penny lab this is likewise one of the factors by obtaining the soft documents of this water drop on a penny lab by online. Water molecules have a dipole, meaning that one side of the molecule has a slightly positive charge and one part has a slightly negative charge. Jun 22, 2018 this lab is simple and doesnt require much in the way of materials. It is a phenomenon that occurs on the surface of liquids when they are in contact with a gaseous medium.
The attraction of a molecule to itself is called cohesion, and attraction between two different molecules is. Finish your lab write up by completing the following sections. Students conduct an experiment to determine how many drops of water will fit on a penny and. The number of water drops that can fit on a penny will surprise you.
How to demonstrate surface tension with a paperclip and water. Make sure that you always read the level at the bottom of the meniscus the bottom of the curve of the water at eye level. Students will learn about the properties of hydrogen bonds and surface tension. How does surface tension beneft water strider insects. Jun 29, 2015 this kind of solution is called a surfactant. The water molecules are holding onto each other and not letting each other fall off the penny. Cohesion is the ability of water molecules to stick to themselves hbonds. This cohesion property results in surface tension because water molecules at the surface of the water puddle attract more to one other than they do to the air molecules above them. Drops on a penny experiments steve spangler science. When the water falls off of the penny, record the number of drops. Covers surface tension, covalent bonding, and cohesion. In the drops on a penny experiment, though, youll experience surface tension and cohesion at their finest.
I distribute a copy of the surface tension lab to each student. Students will test this phenomena in lab groups and compare the water s surface tension with a mystery liquid. The cohesion and surface tension of water becomes apparent when the drops of water you add to the penny reach the penny s edge. Jun 25, 2015 place your penny on a flat, level surface that can get a little wet, such as a kitchen counter. Please consult your current flinn scientific catalogreference manual for general. They experiment with additives to their best soap and water recipes to increase the strength or longevity of the. Record the number of drops for that trial in the table. The surface tension of water describes how molecules on the surface of the liquid attract each other. This lab is intended to reinforce the principles of the scientific method. Measuring surface tension of water with a penny science project.
Check to make sure all of the materials needed are at your lab station. Use an eye dropper to place drops of water on the penny one at a time until any amount of water runs over the edge of the penny. How many drops of water can fit on a penny surface tension. Final lab report the abstract is a short paragraph summarizing purpose, problem examined, results, and outcomes of the lab. Water molecules attract each other and tend to stick together. For the drops on a penny lab experiment, testers use an eyedropper to drop single drops of water onto a penny, and they count how many drops can fit on the surface before spilling over. How is viscosity related to surface tension of a liquid. Surface tension refers to waters ability to stick to itself.
The starting volume is not important, but must be recorded accurately. You might not require more period to spend to go to the books start as well as search for them. How many drops of water can fit on one side of a penny. I then define for students two of the special properties of water that are responsible for the action of the water on the penny in the lab. Penny dropper mini lab how many drops of water do you think will fit on the penny. Surface tension refers to water s ability to stick to itself. The purpose of this lab is to see the steps of the scientific method in action. Draw a picture of the penny and water at a single drop, half full, and near overflowing.
Place the second penny on the flat surface and repeat the experiment, this time adding drops of the soapy water. When water is gently dropped onto a flat surface like a penny, it stays together, forming a small drop, rather than running off the penny. I show students the water dropper tray that i prepared for each group and name each piece of equipment. We will observe and study this property by determining how many drops of water will fit on a penny. Once the water has reached the edge, you begin to see a bubble or dome of water forming on top of the cup. How is the surface tension of water affected by soap. Visualizing surface tension on a penny in this experiment, you will visualize the surface tension of water by dropping water onto a penny with an eyedropper.
The purpose of the experiment is to test the cohesion and surface tension properties of the penny and solution. We discuss the definition for each term and add the terms to our pocket chart containing the vocabulary words for the unit. Aug, 20 you might think that you cant fit many drops of water on the surface of a penny. Cohesion and adhesion investigate the cohesive and adhesive properties of water. Measuring surface tension of water with a penny science.
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