• Science workshop

    Heureka's science experiments to do at home


    On this page you'll find some water-themed science activities to do at home, school, or even at a party! All the science experiments and tricks on this page can be done with supplies you can find at home. There's 6 water-themed science experiments. Below the videos you will find written instructions and a scientific explanations for the phenomenon that occurs in the experiment.

    Science experiments are suitable for the whole family, so they are a fun activity for a rainy day or a change from your weekday evening routine. We wish you insightful moments with science!

  • 1. Go fishing for ice

    Do you know what it feels like to when the fish bits the bait? Try ice fishing this time.

  • Instructions and supplies

    Supplies:

    • ice cubes
    • water
    • cotton thread
    • salt
    • a drinking glass

    Instructions:

    1. Fill a glass with water. Add several ice cubes to the water.
    2. Wet the end of the thread and place it on top of the ice cubes.
    3. Sprinkle salt on the wire and ice. Wait a moment.
    4. Try to lift the ice cubes by pulling on the end of the thread.

  • What happened in the experiment?

    What happened?

    Table salt has two effects on water. On the one hand, it lowers the freezing point of water, and on the other hand, it requires heat to dissolve in water. The "trick" of this trick lies in the latter. When table salt dissolves in water on top of ice, it absorbs heat from the environment. Part of this environment is the water in the string, which therefore gives up heat to dissolve the salt. At the same time, the water in the string itself cools and freezes into ice cubes. The trick doesn't work with a dry string or a string soaked in salt water - at least not as well as with a string soaked in unsalted water. Understanding the physicochemical behavior of different substances is behind the mastery of many magic tricks. One more reason to study these subjects!

    Did you know?

    In winter, roads are salted to keep them from getting icy and to prevent accidents. Instead of table salt, or sodium chloride, calcium chloride is used. Calcium chloride lowers the freezing point of water more than sodium chloride and produces heat when it dissolves. In other words, the opposite of sodium chloride, which requires heat when it dissolves in water and thus cools the solution.

1 2

  • 2. Drop by drop of water

    Amazing! Can water really bend like this?

  • Instructions and supplies

    Supplies :

    • Coin
    • Water
    • Pipette


    Instructions:

    1. Take a coin. Take water in a pipette and drop the water, one drop at a time, onto the coin.
    2. How many drops of water can fit on a coin?
    3. Follow from the side to see what the coin looks like.

  • What happened in the experiment?

    What happened?

    Water has a high surface tension. It is due to the same thing as many of its other special properties. The high polarity of the water molecule, i.e. the oxygen end of the molecule is negative and the other end formed by two hydrogens is positive. The mutual attraction between water molecules is much greater than that between water and air. Therefore, the surface of water is like a taut film that pulls the water surface slightly convex on a coin.

    Did you know?

    You've probably seen water meters "skating" on water. They take advantage of the high surface tension of water.

1 2

  • 3. Heavy water

    Can layers of water be stacked on top of each other? Does the lake freeze to the bottom in winter?

  • Instructions and supplies

    Supplies:

    • Test tube
    • Cold and hot water
    • Pipette
    • Blue and red food coloring
    • Two small glasses or mugs


    Instructions:

    1. Fill one of the glasses or mugs with as cold water as possible. Add 10–15 drops of blue food coloring to the cold water.
    2. Fill another glass or mug with hot water. Add 10–15 drops of red food coloring to the hot water (The hot water should not be scalding hot.)
    3. Pipette 3–4 pipettes of blue water into the bottom of the test tube.
    4. Tilt the test tube and pipette along the edge of the tube, gently squeezing out 3–4 pipettes of red water.

  • What happened in the experiment?

    What happened?

    The density of water depends on its temperature. In the experiment, the cold water dyed blue was denser than the hot water, which is why it stayed at the bottom of the test tube. The hot water dyed red remained lighter, resting on top of the cold blue water. You can experience the same phenomenon when swimming in natural waters in the summer: waters of different temperatures stratify. The water at the bottom is colder and heavier than the water on the surface.

    Did you know?

    Confusingly, the results of the experiment do not apply in every situation: Water is densest when its temperature is 4 °C, meaning it is denser than water at, for example, 2 °C or 6 °C. When we move to the freezing point, the water freezes and ice floats on the surface of the water. Liquid water is therefore denser than water ice.

1 2

  • 4. Floating potato

    How does density affect whether a potato sinks or floats in water?

  • Instructions and supplies

    Supplies:

    • potato
    • knife
    • salt
    • spoon
    • water
    • three transparent and high-sided bowls or glasses
    • food coloring
    • drinking glass


    Instructions:

    1. Cut the potato into three equal parts.
    2. Pour three-quarters of the water into the bowls/glasses.
    3. Pour plenty of salt into two of the containers of water and stir until the salt has dissolved (10 tablespoons to 3/4 liter of water is plenty).
    4. Place one piece of potato in each salt water solution.
    5. Pour warm water into a separate glass and color it with food coloring. Use a spoon to add the colored warm water to the salt water and potato. Do not mix the colored water with the salt water. Where is the potato? What happens?
    6. For comparison, put a third piece of potato in a container of plain water.

  • What happened in the experiment?

    What happened?

    You've just studied a great example of Archimedes' principle. In other words, you've studied the physical principle that explains what makes objects float. The force that lifts an object is equal to the weight of the fluid it displaces. Therefore, objects that are less dense than the fluid will float on the surface due to buoyancy. When an object is more dense than the water, it will sink. In the experiment, the potato floated on the surface of the salt water, meaning the density of the salt water was greater than that of the potato. When you carefully added warm water to it, the potato floated between the layers of water. Fresh warm water is "lighter" and its density is lower than that of the potato, which is why it settled on top of the potato. When you put the potato in regular tap water, it sank to the bottom because the potato was denser than water and therefore did not float. The temperature of the water also matters. The density of warm water is lower than that of cold water. The density of water is at its highest at +4 degrees.

    Did you know?

    In water with a very high salt content, a person can float on its own. Salt water is denser than fresh water. One such place is the Dead Sea on the border between Israel and Jordan. It is located 300 meters below sea level, so it cannot have a river flowing into the sea.

1 2

  • 5. Do not open!

    Test whether your friends or family members can resist the temptation and not open it!

  • Instructions and supplies

    Supplies:

    • empty plastic bottle with cap
    • needle
    • water
    • a waterproof marker


    Work steps:

    1. Use a needle to poke a hole in the plastic bottle.
    2. Write on the bottle with a marker: “DO NOT OPEN”. Cover the hole with your finger while you fill the bottle with water. Close the cap and remove your finger from the hole.
    3. Open the cap or leave the bottle for a curious friend to open. It is best to open it outside or over a sink.

  • What happened in the experiment?

    What happened?

    The water is pushed through the hole into the bottle by air pressure and out of the bottle when the cap is closed by the hydrostatic pressure of the water above the hole. The air pressure is equivalent to the pressure of a 10-meter column of water, so the trick works well with all bottles less than 10 meters tall. When the cap is opened, the water is pushed out by both water pressure and air pressure, causing the water to spray out of the hole.

    Did you know?

    Since the trick is less successful with a large hole and soapy water, one might assume that the surface tension of the water also plays a role. This is true. The surface tension of the water sticks to the edges of the hole and keeps the water inside for its part. If the hole is very small, the surface tension keeps the water in the bottle, even if the cap is opened. Try making a very small hole in the bottle. By squeezing a soft bottle with the cap on, water will spray out of even a small hole, but not from the water's own weight when the cap is open. When the hole is large enough, nothing will hold the water in the bottle. Try it with three bottles with holes "the size of a pinhead", a millimeter and a centimeter in diameter. You may have to chew a little on the physical explanation of this trick. Not everything in the world can be understood without experimenting and wondering.

1 2

  • 6. Strange juice

    How can you make a liquid change color?

  • Instructions and supplies

    Supplies:

    • red cabbage
    • water
    • a jug
    • drinking glasses
    • lemon juice
    • soda
    • detergent/cleaning agent
    • vinegar
    • soap
    • strainer


    Work steps:

    1. Chop, grate or tear a handful of red cabbage into a jug. Pour hot water over the red cabbage. Let the red cabbage juice cool and strain the red cabbage. Pour some of the juice into an empty glass.
    2. Put a little lemon juice in the bottom of another glass so that it is not noticeable. Pour the red cabbage juice on top.
    3. Put a little soda in the bottom of another glass so that it is not noticeable. Pour the red cabbage juice on top.
    4. Try as many color options as possible. Use different substances, such as different detergents, vinegar, and other substances you find around the house.

  • What happened in the experiment?

    What happened?

    The color of red cabbage juice changes depending on whether it is in an acidic or alkaline solution. Red cabbage juice therefore acts as an indicator, i.e. a substance whose color changes can be used to determine the acidity of the solution. Lemon juice is acidic. Red cabbage juice turns red in an acidic solution. Baking soda is an alkaline substance that turns the solution green. The color of red cabbage juice changes from red through violet to yellow-green when the acidity of the solution changes from acidic through neutral to alkaline.

    Did you know?

    Acidity is described numerically on the pH scale. The pH values ​​of an acidic solution are lower than 7. The lower the pH value, the more acidic the solution. A neutral solution, such as pure water, has a pH of 7, and correspondingly an alkaline solution has a pH greater than 7. For example, the pH of an aqueous solution of dishwasher detergent can be as high as 13. This alkaline solution can be harmful to the hands and extremely toxic if ingested. It is worth taking care that dishwasher detergents are not within the reach of small children. In chemical and biological studies, specially prepared pH papers are used. Their color changes indicate the pH value of the solution more accurately than red cabbage juice.

1 2

Check out our other science experiences you can do at home

  • Heurekan nettitestit

    Heureka's online tests

    Heureka's online tests are fun tests with science in them, where you learn new things about yourself and the world around you. Each test has its own theme, and along the way you get science trivia related to the topic. Note! The tests are in Finnish.

  • Heureka-hetket

    Heureka moments

    Heureka moments are videos in which hilarious, funny and startling scientific tricks are performed. They remind us of the ultimate essence of doing science – playful experimentation and the joy of insight. You can test many of the tricks yourself. Note! The videos are in Finnish.

  • Heurekan epäonnenpyörä

    Heureka's wheel of misfortune

    Welcome to Heureka's laboratory, a quiet place of creative destruction. This program series focuses on destroying things in the name of science.

  • Tiedepaja: vesi

    Science Workshop: water

    On this page you will find 6 water-themed science experiments that you can do with supplies you can find at home! The science experiments are suitable for the whole family. On the page you will find instructions and scientific explanations for the phenomena that occur in the experiments.