菜老師的英文教室

The group members:

2.王筱涵Annie、13.陳冠伶 Linda、19.黃庭堅 Cynthia、22.潘宜君 Amanda

Balloon Blow-Up

I need:

³ a bottle with a narrow neck

³ vinegar

³ baking soda

³ funnel or straw

³ water

³ balloon

steps:

1.  Pour about an inch of liquid-half vinegar, half water-into the bottle.

2. Use the straw (or funnel) to fill the balloon half full of baking soda.

3. Stretch the open end of the balloon over the neck of the bottle. Make sure it’s on tight！ Let the heavy end of the balloon dangle so no baking soda goes in the bottle.

4. Hold onto the balloon at the bottle neck, and pick up the heavy part of the balloon so that all the baking soda falls into the vinegar at the bottom of the bottle.

findings:

³ It’s AMAZING！ The balloon will grow！

³ When the baking soda and vinegar reaction are finished (discussions), the balloon will stop bloating.

³ And the bottle will become cool after the chemical experiment！>///<

³ The CO2 is what you see foaming and bubbling in this reaction.

 discussions:

³  The baking soda and the vinegar are mixed and the mixture produces the CO2, which builds up pressure, so the balloon blows up.

(NaHCO3 + CH3COOH → CH3COONa + H2O + CO2)

 ³ The reason of the cooling bottle: Taking away some heat.

 Q: How can you apply this finding to everyday life? Or, can you create anything based on this finding?

A: It can clean dirt. For example*(kitchen, bathroom, clothes, refrigerator)

Raisins City Music Hall

I need:

³ a can of clear soda

³ raisins

steps:

1. Shake the soda as hard as you can.

2. Knock sharply on the top of the soda can 2 or 3 times.

3. Open the soda can, pour it into a glass.

4. Drop in 5 or 6 small raisins.

findings:

³ Wow~ the raisins will start to wiggle around and dance~♪

³ Some raisins can float, some raisins can’t.

³ After we tap on the side of the glass, some raisins float and some sink.

³ Before we open the can, we expect the bubbles of the soda will sharply spurt.

    Actually, the bubbles just effuse out the soda can.

³ The raisins dance in the glass about five seconds(not reallyone minute).(Well, time is too short！We think maybe it’s caused by the soda has been in the refrigerator for 5 years…OAO…or…the raisins are too big！)

³ After the raisins sink, they float up again.

discussions:

³ Because the bubbles adhere on the raisins’ surface, their buoyancy makes the raisins buoy up.

³ The enough bubbles keep the raisins dancing.(up: the raisins are enclosed by many tiny bubbles./down: if the bubbles on the raisins are evaporative and reduce)

Q: Why does the tapping make the raisins sink/float away?

A: The reason of floating: the tapping makes the bubbles gather together on the bottom of raisins fast, so they have enough bubbles to go up.

The reason of sinking: the tapping makes the bubbles on the top of raisins evaporate in the air quickly, so they don’t have enough bubbles to keep the raisins floating.

                                                                                         Mar. 26, 2014