• Glue

• Tape

Over 8 thousand years old, ancient people used glue to waterproof baskets and construct utensils. What did they make it from?

• Cactus plants

• Animal guts

• Human & animal bones

• Animal & and plant materials

What are adhesives made from today? Choose more than one!

• Synthetic (man made) molecules

• Natural proteins & carbohydrates (like vegetable starch or dextrin, milk protein or casein, and tree resin)

• Sticky rice

Glue and tape need both adhesive and cohesive bonds. An adhesive bond occurs between the adhesive molecules & the molecules of whatever it’s sticking to

• True

• False

A cohesive bond happens between the glues own molecules.

• True

• False

Why doesn’t glue in a jar stick to the inside of the jar?

• The jars are non-stick

• The jar is coated with oil

• Glue is dissolved in another liquid (solvent) that prevents it from sticking to the inside of the bottle

• Because glue never dries

There are some glues that use 2 or more chemicals that react and cause stronger bonds than glues that just dry (without a chemical reaction)

• True

• False

What does it mean to say that tape is reversible, but glue is irreversible?

• You can use tape on both sides, but not glue

• You can’t get glue off of things easily once it is dry

• You can re-glue something after it is dry

• You can re-tape something with the same tape

What is Van der Waals forces?

• A permanent bond

• An extremely strong bond

• A bond that only works once

• A weaker reversible bond-like one found in tape

Which has the strongest adhesive bonds?

• Tape

• Glue

• Depends

• Neither