Weather Tools

Warning!
Adult supervision: choking hazards, liquids not for drinking

Please read the procedure before beginning! After reading, please watch the video. Some activities require more time and cleanup than others. You also have the choice of performing these activities in a way that suits your needs.

Not for children under 3 years. Adult supervision required. Follow approved procedures.

Materials

Thermometer
• 4 oz. bottle
• Lid with hole
• Clay
• Pipette
• Clear straw
• Food coloring
• 50 ml isopropyl alcohol
Barometer
• Jar
• Balloon
• Small rubber band
• Boba Straw
• Washi Tape
• Marker
• Scissors
• White Cardstock
Wind Vane
• Clear Straw
• T-pin
• Pencil
• Decorative Cardstock
• White Circle Coaster

Procedure
Thermometer

  1. Locate the test tube labeled ‘rubbing alcohol.’ Add the vial of food coloring to the tube, and replace the lid. Shake the test tube to combine the liquids.
  2. Remove the cap from the test tube and pour most of the mixture into the bottle—leave 5-10 ml in the test tube.
  3. Screw the cap with the hole onto the bottle. Place the clear straw through the hole so that the end of the straw is submerged in the liquid (but not so far that it touches the bottom of the bottle). The straw should fit snugly.
  4. Place a small amount of clay around the straw along the cap to enforce the seal. The seal must be airtight, so ensure that the cap is on tight and the clay is pressed firmly. Save a large amount of clay for the Wind Vane.
  5. Pipette some of the liquid from the test tube into the straw so that it fills to a point above the cap (if the liquid is sinking back into the bottle, it is not fully sealed). Mark the level of the liquid. This point represents room temperature.
  6. Place your hands around the bottle. The level of the liquid in the straw will rise—this indicates that the temperature is increasing! Why do you think increased temperature causes the liquid to rise? What will happen if the temperature decreases, and what can you do to cause this?

Barometer

  1. Using the scissors, cut the neck off of the balloon. Remove the lid from the jar, and stretch the balloon over the top of it so the balloon is flat. Place the rubber band around the balloon to secure it over the jar.
  2. Cut the end of the straw at an angle to make a point. Tape the flat end of the straw to the center of the balloon so that the straw is horizontal.
  3. Place your barometer near a wall and tape the cardstock to the wall. Make a mark on the cardstock where the point of the straw is now—if the pressure increases, the straw will be above that line, and if the pressure decreases, the straw will be below it. Why do you think this happens?
Wind Vane
  1. Using the marker, draw a plus sign (or compass rose) in the middle of the coaster. Label North, South, East, and West in the correct locations near the edges of the coaster (see video for clarification.)
  2. Using the remained of the clay, create a mound in the center of the compass that was drawn on the coaster. This will be the base of the wind vane.
  3. Push the pencil down into the center of the clay with the eraser end pointing up.
  4. Use the scissors to cut a vertical slit in one end of the straw and a horizontal slit in the other (see video for clarification). Slits should be about 2cm deep.
  5. Cut the decorative cardstock in half diagonally to make two triangles.
  6. Slide one tringle into the vertical slit in the middle of the long side, and slide the other into the horizontal slit in the center of the point opposite to the long side. Tape across the straw so that the triangles are secured.
  7. Use the T-pin to carefully poke through the center of the straw, and press it into the eraser on the pencil. The straw will be able to spin around the T-pin.
  8. The wind vane is complete—Take it outside and watch it turn! Use a compass or the Sun (Hint: the Sun rises towards the East and sets towards the West) to determine which direction is North, and orient the wind vane so that you can measure the wind direction! The wind vane will point in the direction that the wind is blowing, and it will turn as the wind changes direction!


Science Behind it!


Thermometer
When liquid is heated, its volume increases or expands (takes up more space), and when it cools, its volume decreases or contracts (takes up less space). The amount of expansion/contraction depends on the liquid. Isopropyl alcohol is sensitive to temperature changes, which is why subtle temperature changes like the heat from your hand can cause it to rise up the straw so quickly! Materials expand when heated because the molecules that make them up gain energy, and when molecules have a lot of energy, they move around on a microscopic level (or at a size that you can’t see or notice). As energy (heat is a form of energy!) increases, the molecules need more space to move, so the material expands!


Barometer
The air that is trapped in the jar will remain at the pressure that it was at the time that it was sealed (as long as the temperature stays the same). Pressure changes when the weather changes—when it is rainy, air pressure is decreased, so the pressure on the outside of the jar will be lower, allowing the balloon to expand and rise above the jar due to the higher air pressure inside the jar when compared to the outside air. When it is clear, the air pressure increases, so the balloon will cave in due to the higher outside pressure.


Wind Vane
Wind can blow in any direction, and meteorologists (scientists who predict the weather) use cardinal directions (North, East, South, and West) to describe which direction the wind is blowing. This can help to predict weather patterns. As air blows past the wind vane, the force causes it to turn in the direction that the wind is blowing, and wind direction can be determined using the labels. Which direction is the wind blowing today?

 

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