How Would You Cool Down On A Hot Day?

What can we use instead of a sponge or a resealable freezer bag if those are hard to find?

If you don't have a sponge, use a clean absorbent washcloth folded to sponge size, and if you lack a resealable freezer bag use a food-safe plastic container with a tight lid while still following the instruction to remove excess air where possible (see 'Press the bag to push out excess air and then seal it tightly').

My pack leaked or didn't freeze flat—what should I check to fix it?

Make sure you 'Squeeze the sponge until it is damp but not dripping,' press out excess air and seal the bag tightly as in 'Press the bag to push out excess air and then seal it tightly,' lay the sealed bag flat in the freezer to freeze for at least 4 hours, and double-bag if you notice leaks.

How can we adapt this activity for younger children or make it more challenging for older kids?

For younger children, have an adult do the freezer steps ('Ask an adult to help you with the freezer' and 'Take one frozen pack out of the freezer with your adult helper') while they do the soaking and labeling, and for older kids let them experiment with different water amounts using the measuring cup and label each bag with the marker to compare freeze times.

How can we personalize or improve the ice pack to make it last longer or look nicer?

Add a few drops of food coloring to the water in the bowl before soaking the sponge, decorate and label the sealed bag with the marker, and make several packs to rotate so each stays colder longer when wrapped in a thin cloth as instructed.