菜老師的英文教室

Balloon Blow-up

Steps:

    1. Pour the liquid–half vinegar and half water–into a bottle.

    2. Fill a balloon with baking soda. (Be sure to concentrate on the powder, not the camera.)

3~4. 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.(Make sure you don't pour any powder into the bottle before you are ready.)

    5.Lift up the balloon and let the show begin!

              WOW!!!

Findings:

    1. The balloon started to grow when the powder fell into the vinegar.

    2. The balloon stopped growing at a certain time according to how much vinegar and baking soda we added.

    3. After the experiment, the bottle would be cooler. (Great in summer!)

Discussion:

    1.  The balloon was filled with CO2, which was produced by baking soda and vinegar.

         (NaHCO3 + CH3COOH →  CH3COONa + H2O + CO2)

    2. The balloon stopped growing because the experiment had finished.

    3. The experiment would take away some heat.

Raisin City Music Hall

Steps:

    1. Get a bottle of soda, and shake as hard as you can!

    2. Before opening it, tap hard on the bottle three times. (We were so scared that we punched the bottle about 10 times.)

    3. OPEN it! (screaming)

(For these three above, we didn't take pictures because we didn't want to risk destroying the smartphone. )

    4. Pour some soda into a container, and drop some raisins into it.

    5. Observing the raisins, count how long they can float.

    6. Do the experiment again. (step4) Try tapping the container and see what's the difference between the two.

Findings:

    1. After shaking the bottle hard and tapping on it, to our surprise, it didn't explode as we thought. (Nothing happened.)

    2. Some raisins could float but the others couldn't.

    3. After the floating raisins sank, they usually would come up again.

    4. When tapping the container, the raisins sank.

    5. The raisins came up again when we stopped tapping.

Discussion:

    1. After shaking the soda bottle, CO2 came out from soda, and was likely to make soda burst; however, tapping was totally different. Tapping made CO2 go back into the aqua.

    2. Some raisins were too big and too heavy for the bubbles of CO2 to carry.

    3. Even if the raisins sank, bubbles from the bottom would carry them up again and again.

    4. Bubbles pressed under the raisins would escape when we tapped so that bubbles wouldn't support the raisins anymore, which made the raisins sink. Likewise, if we stopped tapping, the bubbles couldn't get rid of the raisins, so they would lift up the raisins again.