Question

your class is building thermometer models using the instructions provided by your teacher. what do you predict will happen and why?
a the heat from your hand warms the water inside the bottle. the water expands and pushes itself, causing it to rise up the straw.
b the heat from your hand warms the air inside the bottle. the air expands and pushes on the water, causing it to rise up the straw.
c your hands puts pressure on the air inside the bottle. the air contracts and pushes on the water, causing it to rise up the straw.
d the heat from your hand warms the air inside the bottle. the air condenses and pulls on the water, causing it to rise up the straw.

1. fill the bottle halfway with cold water.
2. add a few drops of food coloring and mix.
3. screw on the bottle lid and insert the straw through it into the water, without touching the base of the bottle.
4. seal around the hole in the lid using play dough, making it airtight and stable.
5. place one hand on the upper part of the bottle.
6. observe what happens to the liquid in the straw.

Explanation:

The experiment involves heat transfer (from hand to air in the bottle) and gas expansion. When the hand warms the air inside the bottle, the air expands (as gases expand when heated) and this increased volume of air pushes on the water, causing it to rise up the straw. Option A is incorrect as it mentions water expanding (water's expansion on heating is minimal and not the main factor here). Option C is incorrect because pressure from hands isn't the main cause (the hand is warming, not applying pressure directly in a way that contracts air). Option D is incorrect as air condensing would not pull water up; heating causes expansion, not condensation. So the correct reasoning matches option B.

Answer:

B. The heat from your hand warms the air inside the bottle. The air expands and pushes on the water, causing it to rise up the straw.