Kyra and Ally are determining how the temperature of iced water
changes with time. Ally is holding a glass of cold water and a
glass of water with ice in it in her hands, occasionally stirring
them. They will measure the temperature every minute, until the ice
has all melted, and then 5 minutes longer.
"Is it getting warmer?" asks Kyra.
"It feels like it is getting colder and colder," replies Ally.
"My hand is just frozen!"
Before you
start, predict what you think will happen, by drawing a graph.
This will make you more aware of what actually happens.
Now do the experiment!
Materials
2 thermometers
2 calibrated cups
mixture of ice and water
(see the instructions below)
timer
The first step is to make a supply of icy water, by
putting 60 ml (1/4 cup) of tap water in an insulated cup and adding about
the same volume of ice. Stir this for a minute.
The result should be 0 C water with lumps of ice floating in it.
Put 60 cc of the 0 C water (but NO ice) in one of the calibrated cups.
Put 45 cc of the 0 C water in the other cup, and then add enough ice to
make the volume total 60 cc.
Measure the temperatures of the two cups, and start the timer.
Hold them in your hand and stir the containers constantly with the thermometers.
Record the temperature
every 30 seconds until the ice has melted, and for 3 minutes more. Also note
what the two cups feel like as you do this.
Note in the data table when the last of the ice melts.
Make a line graph that shows how the temperature of the two cups varied.
(The pages about
graphing might be useful).
Kyra and Ally are determining how the temperature of iced water
changes with time. Ally is holding a glass of cold water and a
glass of water with ice in it in her hands, occasionally stirring
them. They will measure the temperature every minute, until the ice
has all melted, and then 5 minutes longer.
Before you
start, predict what you think will happen, by drawing a graph.
This will make you more aware of what actually happens.