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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

 

DIY Phone Speaker

Boost your tunes and learn some science! We’ll build a DIY phone speaker using common household items. This project is a fantastic way to learn about sound waves, amplification, and the basics of engineering design.

Supplies

  • 1 cardboard tube or paper towel roll
  • 2 paper cups or plastic cups (test the difference)
  • Scissors
  • Pencil
  • Washi tape (optional to decorate)
  • Smartphone

Make a DIY Phone Speaker

Prepare the Tube: Use a pair of scissors to cut a rectangular slit in the center of your paper towel tube. Use the bottom of your phone to trace the opening. This slit should be just large enough to hold your phone securely.

Prepare the Cups: Cut small circular holes in the sides of each cup, big enough for the ends of the tube to fit inside. Trace the end of the cardboard tube on the lower side of each cup to get the right fit. The cups will act as sound amplifiers.

Assemble the Speaker: Insert one end of the tube into the hole in the first cup and the other end into the second cup. Ensure a snug fit, and if needed, use masking or washi tape to secure the tube to the cups.

Test the Sound: Place the base of your phone in the slot on the tube, play some music, and listen! You should notice a significant increase in volume and clarity.

Sound Wave Science

Sound is created when something vibrates. These vibrations move through the air as waves. Think of a wave in the ocean moving up and down — like how sound waves travel, except they move through the air, not water.

When you play music on your smartphone, the speaker creates tiny vibrations that travel through the air in all directions. These sound waves are quite small and spread out quickly, which makes the sound seem quieter.

In this DIY speaker project, we focus on the sound waves by channeling them through paper towel tubes and cups. The tube helps guide the sound waves in one direction instead of letting them spread out. Then, the cups act like amplifiers by bouncing the sound waves inside, making them stronger. As the sound waves bounce and exit the cup, they come out more powerfully, which makes the music sound louder to our ears.

When you listen through your DIY speaker, you hear the sound waves more focused and amplified. This shows how engineers use materials and design to control sound and make it louder or clearer. This kind of science can be found in real speakers, headphones, and even large concert sound systems!

Extension Activities

  • Experiment with Different Sizes: Try using larger or smaller cups to see how the size affects sound amplification.
  • Add Decorations: Customize the speaker with washi tape, paint, or markers to make it uniquely yours while testing if the decorations affect the sound quality.
  • Explore Sound Science: Research different types of speakers and how professional speaker designs utilize similar principles for amplifying sound.

 

Idea taken from the blog LittleBinsforLittleHands

LEGO-Sudoku

Instructions for adults:

  • Print out the sudoku boards and laminate them if you wish.
  • Cut the papers in half so that each board is on its own A5 size paper.
  • There are three levels of difficulty in the main house sudoku: one star, two stars and three stars.
  • Watch the Häärämö YouTube channel to see how handy it is to guide your child to solve sudoku puzzles.

Guide for your child:

  • Count how many squares of each colour are on your game board. You need a total of four of each of the four colours.
  • For example, if you have three blue squares on your board, how many more do you need to make four blue squares in total? So take one blue Duplo piece.
  • Place the Duplo pieces you have taken above the board in the colour order you have chosen, so that one colour is always at the bottom (see picture above). For each Sudoku, you will need 1 to 3 of each colour.

Solve the sudoku:

  • Find the row with only one colour missing.
  • When you can no longer find rows with only one colour missing, look at the large square (2 x 2 square). Which colour is missing? In addition to the previous solution strategies, take aside the two colours that are missing from the row or the large square. Decide from the horizontal and vertical lines where the colours belong.
  • Only put a colour in place if you are sure that it belongs there. If you think a colour can be placed in two different squares on the same row, don’t place it yet.

Sudoku boards: Lego-sudoku Eng (PDF, 117 kB)