British Sign Language Glossaries of Curriculum Terms

BSL Chemistry Glossary - endothermic - Laboratory video

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This is a different kind of reaction - it absorbs heat (it is endothermic). I'm going to show you an example.

I'm going to take 5 grams of each of these chemicals (see screen). This is balsa wood - I'm going to add a couple of drops of water to it and then put a beaker on top of it. We are waiting until the water is at room temperature.

I have now added the two chemicals and am going to mix them together.

(1.32) When I mixed the chemicals together I could feel that the beaker was becoming colder. Let's check the temperature. It has decreased!

(1.52) It is now around 15°C!

(1.55) Now it is about 10°C.

(2.07) It is down to about 5°C now!

(2.13) The temperature keeps going down!

(2.18) It is almost at 0°C!

(2.33) The water has become ice. This is an example of an endothermic reaction.