science experiment

Simple Science: Cartesian Diver, learning about buoyancy

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Do this fun experiment/ game to learn about buoyancy and air pressure.

 Cartesian Diver game with water bottle for kids Supplies:

2 hex nuts
2 pipettes
2 wires (we used red and blue)
1 500ml plastic bottle with lid
water

 

  1. Snip the pipettes about 2/3 of the way up.  You will be using the bulb part.
  2. Slip the hex nut onto the pipette bulb and screw it onto the base of the bulb to secure it
  3. Wrap one end of blue wire around stem stump of pipette, curving the other end to make a hook
  4. Wrap the red wire around end of second pipette, starting at the stem, looping it around top of pipette bulb, and securing back at the stem

make a cartesian diver

5. Fill each pipette about 1/2 full with water by squeezing bulb, putting into water, and releasing bulb.

6. Test the buoyancy of each pipette bulb – fill the red one with enough water to make it sink in a cup of water.  It will probably be just over half full with water.  Fill the blue pipette so that it floats in a cup of water, just below the surface.  Ajust water levels in each pipette to get correct buoyancy.

testing cartesian diver experiment for kids testing cartesian diver experiment for kids

 

To play the game:

Fill a 500 ml bottle with water.  Drop the red pipette into the bottle.  It should sink to the bottom.  Drop the blue pipette into the bottle.  It should float almost at the surface.  Make sure the bottle is completely full with water, and secure lid.  Gently squeeze bottle.  When you squeeze the bottle, the floating pipette should dive down.  Try to hook the pipette that is sunk, and bring it to the surface!

make a game to play using science

How it works:

Buoyancy: when your pipette is less dense than the water it is in, the pipette will float.  When the pipette is more dense than the water it’s in, it will sink.  The combination of nut + water + air in the pipette will be just heavy enough to sink if you add more water, and float if you add less.

Pressure: When you squeeze the bottle, you are increasing the pressure, making the air trapped in your pipette compress, which means more water can creep into the pipette.  This makes it makes less buoyant causing it to sink.   When you release your squeeze, the air expands, pushing water out of the pipette, making it more buoyant so it floats.

 

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Simple Science for Kids – Spring Break Volcano Eruption

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There are sure to be at least one or two eruptions in your household over spring break, so why not make your own!! Here’s a great way to pass the morning with your kids while on spring break.  Once the volcano is built, you can make it erupt over and over again – we kept ours around for a few days!

To make your volcano, you will need:

Salt Dough:

  • 3 cups flour
  • 1 cup salt
  • 2 tablespoons oil
  • ~ 1 cup water

Volcano form & lava:

  • warm water with a few drops red food colouring
  • 2 tbsp baking soda
  • 1/2 cup to 1 cup vinegar
  • large baking sheet with a rimmed edge (could use a 9×13 cake pan instead)
  • Clean, empty soup can (10 oz)  You could use an empty pop bottle instead, but we liked the can because it was easy for my son to manage building around it and pouring ingredients in the wide opening without any help, and it’s small enough to get a quick ‘eruption’

Mix the salt dough:

Make salt dough home made play doughMeasure Dry ingredients

how to make homemade playdough

Add the wet ingredients

making home made play dough

Stir to combine, then knead until smooth.  You may need to add more flour or water if too wet or too dry

making a play dough volcano

Play Dough ready for modeling our volcano

To make the volcano:

Kids science experiments how to make volcano

Place clean can in centre of baking sheet.  Form dough around can in a cone shape

Kids Science experiment - volcano eruption

My guy decided to carve some flow lines into his volcano (from where it had previously erupted, he explained)

Science for Kids - Making a volcano

Fill can with warm coloured water to ~ 3/4 full

Volcano experiment with kids

Add 2 tbsp baking soda and stir to mix.  Now for the fun part:

ADD VINEGAR!

Simple Science experiment for kids volcano eruption

Watch the lava flow over the volcano!  You can add more vinegar once the eruption settles down.  We did this over and over again!  Might have to dump everything out and start with more baking soda if your volcano no longer erupts.

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