Prior Knowledge Question (Do these BEFORE using the Gizmo.)
Eduardo hurts his knee during a basketball game. The trainer applies a cold pack, which gets cold after being
squeezed. The next day, Eduardo’s friend Beth is
...
Prior Knowledge Question (Do these BEFORE using the Gizmo.)
Eduardo hurts his knee during a basketball game. The trainer applies a cold pack, which gets cold after being
squeezed. The next day, Eduardo’s friend Beth is going sledding. Beth buys some hand warmers and puts
them into her gloves. All morning, her hands stay toasty warm.
1. Where do you think the “cold” and the heat comes from?
Gizmo Warm-up
As you have probably seen with instant cold
packs, hand warmers, and the MRE Flameless
Ration Heater, some reactions absorb energy
while others release it. In the Feel the Heat
Gizmo, you will explore these energy changes
while making your own new MRE Flameless
Ration Heater. Below are the solids, and their
names, to be tested that are in the blue lid bottles
resting on the shelf in the upper right hand corner
● CaCl2 = Calcium Chloride (1st bottle)
● NaC2H3O2 = Sodium Acetate (2nd bottle)
● NH4NO3 = Ammonium Nitrate (3rd bottle)
● KCl = Potassium Chloride (4th bottle)
● NaCl = Sodium Chloride (5th bottle)
● NaBr = Sodium Bromide (6th bottle)
To begin, drag a bottle of NaC2H3O2
(sodium acetate, the 2nd bottle) from the shelf to the
‘Drag container of powder here’ spot directly below.. Using the sliders for Water Volume
(mL) and Powder Mass (g) on the bottom right of the screen, select 100 mL for the water
and 20 g of powder to add. Note the beginning temperature, and then press Play ( )
located in the bottom left of the screen to see what happens to the temperature, measured
in Celsius (ºC).
Click the reset button ( )
2. Experiment with different powders by clicking and dragging the one on the table back to the shelf and then
dragging a new container down to the ‘Drag container of powder here spot’ until you find one that produces
the opposite effect on the temperature.
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The “cold” comes from an endothermic reaction, bonds are being broken allowing
energy to be absorbed causing something to become cold or cook. the heat comes
from an exothermic
1. Did the temperature go up or down? Up
When a powder dissolves in water a solution is formed. The powder is the solute and the water is the
solvent. Oftentimes energy changes accompany the formation of a solution. When added to water, some
powders cause the resulting solution to get hot, while others make it cold. Some powders don’t produce a
temperature change at all. When energy changes do occur, they can be put to good use.
Introduction: The reactions in this activity are performed within a calorimeter, an insulated device that keeps
heat from escaping, enabling you to accurately record temperature changes.
Question: Why does the temperature change when a powder is dissolved in water?
1. Get the Gizmo ready: Drag a bottle of NaC2H3O2
(the 2nd bottle) from the shelf. Set the Water volume
to 100mL and the Powder mass to 20 g.
2. Observe: In between the hot plate where you read the temperature and the ‘Drag container of powder
here’ spot click to check and turn on “Show molecular view”, and notice the water molecules.
a. What color line represents the bonds between the water molec
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