Kategori: English

Volume Exploration

What do the concepts mean more, less and as much? What about bigger and smaller? Can it be investigated experimentally?

For example, you can drink water up a glass and consider whether two glasses of water is more or less than one glass of water. What happens if everyone drinks two glasses of water? Does one then drink more or less than the other? Or does everyone drink the same amount?

You can also compare two water glasses of different sizes. Which is the biggest and which is smaller?

Step 1 Materials

  • Water
  • Measuring cup
  • Containers of different sizes and shapes (narrow, high, low…)

Step 2 Operation

We put all the containers on the table. Let’s think about which container holds the most water? Measure how much water the children think can fit in the largest container.

Try and see if this amount of water can fit in any other container. Measure how much water the children think can fit in the smallest container. How many times does this amount of water fit in the largest container to fill it?

What about other containers? Consider if there are any containers that are different in shape but can hold the same amount of water. For example, fill two containers to be examined with water to the brim. Then a measuring glass is taken, the water from another container is poured into it and the amount is read. Empty the measuring container, pour water from the remaining container into the measuring container and read the amount. Compare these numbers.

Step 3: Why

The amount of water can be used to observe the concept of volume. Volume is all the space left inside the edges of the container. The volume can be very small, even if the container is large. On the other hand, the volume can be large, even if the container is shallow.

 

Floating flowers and surface tension

What have you seen floating or jumping on the surface of the water?

Step 1 Materials

  • Paper
  • Pens
  • Scissors
  • A large flat container
  • Water
  • Wool yarn
  • Soap
  • Two plastic cups

Step 2 Implementation

Let’s start by preparing the flowers.

  • Draw a flower on a piece of paper with a middle part larger than the petals.
  • Cut out the flower from the paper. The flower can be decorated with crayons.
  • Fold the flower petals inwards in order.
  • Think about: Will the flower float in the water.
  • Place the flower into the water.
  • Think about: Why are the flowers opening up in the water?

Step 3: Why

The flower opening is a capillary effect. The structure of the paper has small tubes through which water can penetrate to travel upwards. This makes the flowers open the petals.

Step 4 Implementation

What happens to wool yarn if it is put in a plastic cup with water.

  • Use two different plastic cups, one with only water, the other with some added soap.
  • What is happening? Why?

Step 5: Why

The soap reduces the surface tension of the water and causes the wool yarn to become wetter and sink. to the bottom of the earth.

 

Source: Rehunen, Kirsi. Tiedeleikkejä pikkututkijoille.

Make Your Own Stethoscope

Introduction

Have you ever wondered what happens to the heart as we exercise intensely? How does its beating change? A doctor can figure this out by using a tool called a stethoscope, which is a long, thin plastic tube that has a small disc on one end and earpieces on the other end. In this activity, you will make a homemade stethoscope and use it to measure peoples’ heart rates at rest and after exercising.

Materials

  • Duct tape or other strong tape
  • Scissors
  • Plastic funnel
  • A cardboard tube from a paper-towel roll
  • Stopwatch or clock that counts seconds
  • A volunteer who can safely exercise intensely for one minute

Procedure

  1. Put the narrow end of the funnel into the cardboard tube.
  2. Using a strip of duct tape or other strong tape, tape the funnel and cardboard tube together. Make sure there are no gaps or spaces where you tape them together.
  3. Your stethoscope is now ready to use! Practice listening to the heartbeat of a volunteer by putting the funnel on the left side of the volunteer’s chest. Make sure the funnel is flat against their chest. Put your ear against the hole at the end of the cardboard tube. Do you hear the heartbeat?
  4. Tip: If it is noisy or the volunteer is wearing thick clothing, it may be hard to hear the heartbeat, so you may need to adjust conditions accordingly.
  5. After the volunteer has been resting in a chair for a few minutes, listen to the heartbeat and count how many times it beats in 10 seconds.
  6. Multiply this number by six. This is the resting heart rate of the volunteer in beats per minute (bpm).
    What is the volunteer’s resting heart rate?
  7. Ask the volunteer to exercise in place for one minute by doing jumping jacks or running in place. Right after the volunteer has stopped exercising, listen to the heartbeat and count how many times it beats in 10 seconds.
    Why do you think you count heartbeats for only 10 seconds? What happens if you count for a longer period of time after exercising?
  8. Multiply this number by six. This is the heart rate right after exercising in bpm.
    What is the volunteer’s heart rate now? How did the heart rate change after exercise? Why do you think it changed like it did?
  9. Think about how regularly exercising may change a person’s heart. If a person regularly exercised, how do you think this would change his or her heart rate? How do you think that person’s heart rate during rest and exercise would be different?

What Happened?

When people exercise, their bodies need more oxygen, and consequently their hearts beat faster and their heart rates increase. This is why you most likely found that when your volunteer exercised, the heart rate increased compared to the resting heart rate. In addition, genetics, gender, age, and health all affect people’s heart rates. The heart rates in people who exercise regularly usually will not increase as much during exercise. Regular exercise strengthens the heart so that it does not need to work as hard to do the same amount of exercise.

While you can determine someone’s resting heart rate by counting the number of beats in 15 seconds and multiplying by four to get the beats per minute (bpm), to calculate a heart rate immediately after exercise it is better to count the number of beats for 10 seconds and multiply that value by six (to get the bpm). Because the heart will quickly slow down after exercise, the heart rate should be measured immediately after a person has stopped exercising (or while they exercise, if possible).

Use Chemistry to Lift Ice Cubes

Introduction

Have you ever wondered why salt is used to de-ice roads? Did you know that snow sticks more readily to pavement that has been treated with salt? Why would this be the case? In this activity, you will use the same principles to hoist ice cubes with a piece of string. Is it possible to do this without getting your hands cold? Try the activity and see what a pinch of salt can do!

Materials

  • Four glasses
  • Cold water
  • Ice cubes
  • Salt
  • Four pieces of string, each about 20 centimeters long (yarn works well.)
  • Two sticky notes
  • Watch or timer
  • Thermometer (optional)

Prep Work

  1. Gather all of your materials on a work surface that can tolerate spills.
  2. Fill all four glasses with cold water.
  3. Put a few ice cubes in each glass of water. They will float because ice is less dense than water.

Procedure

  1. Find an ice cube with a surface at water level. Lay one end of a piece of string across that ice cube.
    Do you think the ice will stick to the string?
  2. Lift the string.
    Does the ice cube stick to the string? Why do you think this is the case? Can you think of a way to lift the ice cube with string without touching the cube?
  3. Try again with the second glass, but now, sprinkle some salt over the string and ice cube. Mark this glass with a sticky note.
    Do you think the ice will stick to the string if you lift it?
  4. Lift the string.
    Does the ice cube stick to the string? What do you think would happen if you left the ice cubes out for a few minutes with the strings on top?
  5. Take the other two glasses filled with water and ice cubes.
  6. For both glasses, lay one end of a piece of string across an ice cube with a surface at about water level; let the other end of the string hang over the edge off the glass.
  7. Sprinkle salt over the string and ice cube in one of the glasses and mark this glass with a sticky note. Wait two to three minutes.
    Do you think the ice will stick to the string after you give it some time? Will both ice cubes, just one ice cube or no ice cubes stick? Why?
  8. After about two to three minutes, lift one string at a time.
    Can either string pick up the ice cube? Can you explain what you see?
  9. If you cannot pick up any ice cubes, try again, but wait a little longer this time.

What Happened?

Could you lift the ice cube you had sprinkled with salt and left untouched for a few minutes? Did you fail to pick up the cube in all other cases? Why does this happen? First, the ice around the string melts when you sprinkle it with salt. Then, the string freezes to the ice cube.

When you sprinkle salt over ice, it dissolves into the thin layer of water above the ice. Because salt water freezes at a lower temperature than pure water, adding the salt makes some ice melt and absorb heat in the process. The area around it thereby cools and freezes water molecules to the ice cube, also freezing the string onto the cube. Without the salt, the water and ice remain at the same temperature and the string does not freeze to the ice. In both cases, the ice cube gradually melts as it absorbs heat from the air around it, but without the salt, the string cannot freeze to the cube.

If you used sugar, you would see the same effect: the cube sticks to the string. Dissolving other substances in water will also lower the freezing point and create the same effect.

How Empty Is an Empty Bottle?

Introduction

Did you know that airplanes and sound have something in common? Can you guess what it might be? Air pressure! It is fascinating how air—something that is so fluid and invisible—can power an amazing number of fascinating phenomena. In this activity you will use your own breath to blow a small paper ball into an empty bottle. It sounds simple, but is it? Try it out and see for yourself!

Materials

  • A four-by-four-inch piece of printer paper
  • Plastic wide-mouth bottle, roughly 500 to 800 mL (If you need to use bottles with a regular opening, use a two-by-four-inch piece of paper to create the ball .)
  • Table or other flat surface
  • Helper
  • Optional: Small balls
  • Optional: Other bottles or jars
  • Optional: Drinking straw

 

Prep Work

  • Crumple the four-by-four-inch piece of paper into a tight ball. The ball should easily pass through the opening of the bottle.

Procedure

  1. Lay the bottle on its side with its mouth facing you. Ask a helper to hold the mouth down so it touches the work surface.
  2. Place the paper ball in front of the bottle’s mouth, about 5 centimeters away from the bottle.
  3. In a moment you will blow the ball into the bottle. How challenging do you expect this to be?
  4. Try it out! Is it as you expected?
  5. Switch places with your helper. Can they blow the ball in the bottle?
  6. Brainstorm ideas that can make blowing the ball in the bottle easier. Try out the ones that sound most promising.
  7. If some work, what do you think makes these solutions effective whereas others fail?
  8. Looking at a similar situation might help explain why it is surprisingly hard to blow a paper ball into a bottle. Try rolling or flicking the ball into the bottle.
  9. Is that difficult? What is different when you roll or flick a ball compared with when you blow a ball?
  10. Lay the cardboard tube with an opening facing you. Place the paper ball about 5 cm in front of the tube’s opening.
  11. How challenging do you expect blowing the ball into the tube will be?
  12. Try it out.
  13. Is it as you expected?
  14. Compare the tube with the bottle. 

What is different and what is similar? What difference could make it more difficult to blow the ball in the bottle? Can you find ways to test your explanation?

What Happened?

It was probably almost impossible to blow the ball into the bottle without using a tool—but easy to blow it into the tube or roll it into the bottle.

Although the bottle and the tube seem empty, both are filled with air. The air in the tube can freely flow out at both ends of the tube, whereas the air in the bottle can only leave through its mouth.

When you blow you create a current of air, and the movement of air can take a light ball with it. When you blow toward the tube the air in front of the tube pushes the air that is already in the tube out on the other end. The ball follows the flow of air and enters the tube. When you blow toward the mouth of a bottle it is as if the air you blow and the ball following this flow of air bounce off the air that is already inside the bottle—because that inside air has nowhere to go. The ball does not enter the bottle.

You can also use Bernoulli’s observation to explain why blowing the ball does not push the ball into the bottle. The air inside the bottle is moving slowly, so it is at a higher pressure compared with the fast-moving air in front of the bottle (the air you just blew). Because air always tries to reach equilibrium the air from the bottle (the high-pressure region) will flow out of the bottle toward the low-pressure region and take the ball with it.

When you roll the ball into the bottle air can simultaneously move out of the bottle through the bottle mouth while the ball is rolling in. In order to successfully blow the ball into the bottle, you need to concentrate the air you blow onto the ball—instead of letting the air go around it. A drinking straw can help you do that.

Symmetry

Make mirrored images with Lego

Supplies

  • Lego baseplate x 2
  • Lego Pieces

Procedure

Take the baseplate and calculate where the center point is. Build a dividing line at the midpoint with a single color.

Make a pattern with different pieces on one side of the board. When you attach the brick to the baseplate, move a similar piece to a pile on the other side. Once you are done with the pattern, check that you have placed the same pieces that you used to make the pattern.

Give the half-filled base plate to your partner. Also, swap the loose blocks with your pair. See what pattern the couple has made on the other side of the plate. Make a similar pattern to a game on the other side of the center line using the pieces you’ve been given.

Challenge

  • Make a half-pattern without a midline with a partner.
  • Look at your surroundings and see what you find that is symmetrical.

Raft Design

Building a boat, raft, or other watercraft to safely transport items across water is a way for children to practice planning and decision-making skills. Gather your materials beforehand, and try the activity along with him!


Materials Required

    • A large bowl, tub, or other container filled with water – even a bathtub can work
    • A variety of materials for building a vessel, such as:
      • Sticks
      • Foil
      • Corks
      • Paper
      • Egg cartons
      • Tape
      • Glue
      • Rubber bands
    • Items to transport, such as coins, pens, small toy figures, etc.

Tips for Adults

  • As children begin to select materials to build their vessel, encourage them to try out ones they are unsure about. They can test the material in the water to see if it floats before deciding whether or not to incorporate it into their design.
  • Take the time to think and make a plan before diving into an activity, but it’s an important skill to practice. Planning is part of a suite of skills that helps children’s brains be ready to learn.
  • If children make mistakes or if their design doesn’t work, encourage them to learn from the failed attempt and to continue improving and adjusting their design. Ask questions like:
    • What could we change so it will work better next time?
    • What could you add to your design to help it travel across the water without anyone touching or pushing it?
    • What additions or changes can you make to your design to help it support even more weight?

https://youtu.be/NUolm-d9IeI